I ONLY SHIP TO THE U.S.
Distilling The Wash
This information is provided by www.homedistiller.org
Distilling the Wash
The alcohols in the wash begin to vapourise from the wash around specific temperatures. If by themselves they would be ...
Once together, a mixture of several of them will be slightly different however. You no longer get them coming off seperately, but always as a mixture. Fortunately for us though, each of the species will tend to dominate around its boiling point temperature, thus we know whats "mostly" coming off at that point. By tracking the temperature of the vapour, you have a fairly good idea when you're collecting the Ethanol your after (78-82 °C), vs when it is starting to get lean and you're into the higher alcohols.
Note that you may also need to adjust the temperature if you are distilling at altitude - the higher above sea level you are, the lower boiling temperatures become because of the reduced air pressure.
Filling the BoilerWhen filling the boiler, make sure you leave enough headspace above the liquid, so that if it foams up a bit, that the foam won't get pushed up the column. Typically it should only be around 3/4 full.
You also want to ensure that there will be enough liquid at all times to completely cover the elements. This is particularly relevent when you've already done some "stripping" runs first, and you're now starting with something quite high in purity (eg 45%) and the reduction in volume will be greater.
Some washes may tend to foam up a bit & get pushed out through the column & condenser, contaminating the clean spirit. This sometimes means that for some washes you may have to leave your boiler 1/3 to 1/2 empty at times, in order to accomodate that foaming. Hogan writes about how to deal with this ...
Removing the MethanolBe ruthless about tossing the first 50 mL (off a 20L wash) that you collect, as this contains any methanol (causer of hangovers - small quantities, or blindness - larger quantities). Even though I'm pretty sure I only collect less than 10mL at the methanol stage, I still discard 50mL, just to make sure. No need for penny-pinching when you're making 3L of the stuff, for less than $5. If you're using a potstill, you may need to increase this amount you toss up to 100-200 mL.
Jack writes ..I have tasted potstill alcohol that has been made both ways- when only 50ml (per 20L) was thrown out, the stuff was very sharp tasting. It became alot smoother when a full 100ml was thrown out at the start of the run.
This first portion is often called the "foreshots". They are different from the "heads". Ian Smiley (http://www.home-distilling.com/) describes foreshots as "the low boiling point compounds that come out of the still first. They contain acetone, methanol, various esters and aldehydes, and other volitiles. Foreshots are to be considered poisonous and should be discarded." Whereas heads "come out after the foreshots, and are almost pure alcohol, except that they are contaminated with trace amounts of unwanted cogeners ..." To get a really clean distinction between the foreshots and the heads, first ensure that you've let your column equilbriate under total reflux, then hold the reflux ratio high, such that you remove the foreshots only very slowly (eg 1 drip per second), thus allowing an equilbirium to be maintained at the top of the column, encouraging the methanol to collect there.
If you're after making pure neutral spirit for vodkas or gin you may choose to keep the heads (eg the next 250 mL-1L of spirits) separate from the following couple of litres (middle run) on the basis of their taste. These heads can still be used to make liqueurs, whisky, rums, etc, or redistilled later if desired totally neutral. The only problem with heads is their non-neutral taste.
The distinction between the various phases depends on what sort of still you have. They will all tend to merge from one to the other. This is particularly the case with a pot still, where you notice the temperatures always slowly changing as the distilling run progresses. Using a reflux still or fractionating column will allow the various stages to appear more distinct, as the temperature will be more stable, due to the more distinct seperation of each compound.
Running the StillFor neutral spirits. there are many different ways of running a still to achieving the same results.
To get high purity, you require your column to be doing many redistillations. To get enough redistillations happening, your packing must offer sufficient "theoretical plates". The HETP that you get from packing depends on many factors, but includes the surface area, the thickness of the liquid spread out over it, and the ratio of liquid to gas. As the alcohol in the pot depletes, in order to keep the same purity, you need more redistillations happening. The usual way to do this is to improve the HETP by increasing the ratio of liquid to vapour (eg the reflux ratio)
As its a ratio, you can do it either by increasing the amount of liquid being returned (eg increase the amount of cooling water to through tubes/top condensors, or closing the offtake in a Nixon-Stone ), or by reducing the amount of vapour (by reducing the power input to the boiler). Both will have the same result.
Just how much action is required depends on what the column is like to begin with. If its a tall column, packed with something with heaps of surface area (scrubbers), etc, it may already have enough redistillations happening in it to satisfactorily cope with very low alcohol input. Thus there would be no need to adjust it much during the course of the run. You'd basically turn it on, set it and leave it (though you still need to catch it right at the end).
If however the column isn't quite so great, you might need to do some serious readjusting of the reflux ratio right through the run in order to keep it doing what you desire.
Likewise, with the tall column, maybe you elect to run it heaps faster at the start (and not suffer any ill consequences), but then progressively turn it back down as things progress. Eg - do you run it the whole run at say 10 mL/min offtake, and never touch it, or say start at 50 mL/min and then slowly wind it back to 10 mL/min over the following hours.
None of these are wrong or right, just different. So when you hear of guys doing 17hr runs, thats fine if it suits them. I prefer the latter of fiddling to get the shortest time. Each to their own. With rushing, I have more "oops" happening - finding that I haven't been checking it quite routinely enough, and that its just spent the last 10-15min at too high a temp. But I'm still happy with the final taste, so thats fine for me. Others may shun my juice.
Choose for youself - try a run at a really slow offtake & little control needed, and compare against a "hands on, push it fast" approach. Maybe choose the middle ground.
Likewise as to go to electronic control or not - its just a personal choice, based on if the smoother control is worth the cost, if whether it will work for your style of operation & still design, if you dabble in that sort of thing, or if you prefer the hands on and driving.
When to FinishThis really depends on what your still is like - they can all be different. The general rule is to finish distilling when the vapour temperature near the condensor is around 92-94 ° C. Depending on how much of the "tails" you collect, your spirits will aquire a different flavour. If making a neutral spirit, you wouldn't want any tails present, so you'd finish sooner (around 82 C?), however if making a flavoured spirit, you'd want a trace of them present. Note that you can always collect the tails seperately from the "middle run", and redistill them at a later date to get the ethanol from them.
If your column is a very high purity one, you may infact find yourself finishing before 82 C, with only a small amount left to collect as tails after that.
If you're doing a flavoured spirit, eg a schnapps or whisky, often the "cut" to finish will be based on taste rather than by temperature alone.
One clue that you've gone too far is if the distillate takes on a white/milky appearance. This is because the fusels (propyls, amyls & butyls) are partialy/totally insoluble with the higher %alcohols. You won't spot them if you keep your tails separate, as they are soluble within their own family in a weak ethanol solution. You may spot them though by seeing if a drop on the end of your finger gives a sun glint, and/or feels well lubricated (the old moonshiners trick). You may also see a slight film/slick on the surface of the distillate if using a clear container. If you can see them, then you can probably smell them too.
Another indication that its time to finish is when the temperature begins to fluctuate a bit. Tarvus writes :
For example, near the end of the time the foreshots are exhausted and the ethanol begins running, the temp will fluctuate dramatically after having held rock steady until then. The same seems to happen at the end of the ethanol run. When I see the temp starting to get squirrely, I stop the run. Maybe I leave a bit of usable ethanol in the wash, but it's worth knowing the stuff I collect is pure! :)
Let the distillate drop cleanly into the recieving vessel, so that it splashes. This will help it lose any fusels that may be present. For the same reason, it is better that the distillate is still warm to the touch, not cold. Don't put the end of the tubing under the level of the liquid, as this will cause any fusels that might be coming out as vapours to condense (and taint the flavour).
Greed is a bad thing. This is what gets your mates saying that your spirits taste "off" (you stopped noticing a while back, but everyone else still comments). You are either trying to rush things (good distillate requires time & patience), or you're wringing the neck of the beast and taking the run too far. You can't get ALL the available alcohol out of the wash. The better your still (eg the more "theoretical plates" / smaller HETP it has) the better your chances, but you still run the risk of contaminating your clean spirit with the tails, and having it smell & taste bad. But heres a few things to try ..
A 20L wash (at 12%) should produce approx 3L of 75% ethanol via a basic reflux still, or 2.3L of 95% ethanol via a fractionating reflux still.
Donald advises ..
Neutral spirits require little to no age (0-30 days). Using refined raw materials helps produce more neutral distillate and reduces tails.
Tails are always volitle, oily and rancid. Once they come over they will dominate/spoil the flavor of the entire batch. I suggest having 3 recieving containers on the output side: center cut, orgaoliptics, heads/tails. That way if tails start on the oganoliptics the entire batch is not at risk. The danger/fun is that the organoliptic range changes with the raw material. In general tails are: Early- tequila, Armagnac, Cognac. Moderate- Brandy, Irish style (3x) whiskey, Corn whiskey, Rye whiskey, Bourbon, American whiskey. Late- Malt whiskey and distilled spirit specialties.
Each style and flavor profile has it's own target cuts for optimun results. The cuts differ a few points between companies and account for "house flavors" & "regional traditions". The shape and composition of each still (or addition) effects the reading of cuts as well. A short pot still will give a stronger and hearty spirit with early oily tails, whereas a taller onion dome pot still will give a lighter spirit with a later tails. This means that with good hydrometers, anybody with any still, can produce the target flavor with the proper cut. Much money is spent on still improvement, before tool improvement.
Save money by using good tools and accurate measuring equipment.
To keep aware of the temperature getting too high at any stage, theres several digital thermometers coupled with alarms available. See http://www.kitchenkapers.com/36290.html Brian wrote: ...
Jack advises ...
Now, for the good stuff: Most pot stills that are run commercially are run until one-third of the mash volume has been collected (3 gallons of wine gets reduced down to 1 gallon of "low wines"). The second run has the spirit collected when it starts coming out of the still at 75%abv, and you stop collecting at 55%abv. The stuff that came out stronger than 75%abv is thrown out as heads. The stuff that comes out lower than 55%abv is saved as feints, and added to the next run. The feints are added to the next beer stripping run if a lighter, more neutral spirit is wanted- common in Cognac distilleries, not with whisky, though. If the feints are added to the next spirit run, the resulting spirit is a bit more flavorfull- this is how whiskey is distilled. The total spirit collected tends to average somewhere in the mid-60%abv when collected in this style.
The 75% to 55% cutoff points are known as a "middle-third cut" among distillers, and is the industry standard for most (except Glenmorangie, which collects only from 75% to 65%abv- this is called a "middle-fifth cut").
SaltMaurice advises ..
The "Household Cyclopedia" recommends ...
David cautions though ..
Bokakob advises ..
Ken recommends using Sodium Carbonate to reduce the amount of fusel oils present ..
Rob details the bicarb advantage too:
1. A well run column distillation will separate a mixture into fractions based on the boiling points of the components.
2. There will be some overlap in most real-life stills.
3. ethyl acetate can be smelled at very low concentrations
4. acetic acid cannot (it has a higher flavour threshold)
5. under neutral or acidic conditions acetic acid will esterify to some extent in the presence of ethanol.
6. sodium acetate is not volatile
7. sodium bicarbonate will neutralise acetic acid.
8. sodium bicarbonate may hydrolyse ethyl acetate to a greater or lesser extent.
9. Adding sodium bicarbonate at some point between a stripping run and final distillation has the effect of decreasing the volume of fractions collected which smell of ethyl acetate.
10. Adding sodium bicarbonate at some point between a stripping run and final distillation has the effect of making the main fraction "cleaner smelling"
11. without bicarb the main fraction _can_ smell of ethyl acetate (ymmv)
12. Sodium acetate is not esterified by ethanol.
1. Why is there ethyl acetate in the fractions after the heads? (no NaHCO3)
2. What does NaHCO3 addition do?
3. How do we best (read easiest) use it?
Rob's Answers/Opinions (currently!):
1. During distillation (after column stabilization) ethyl acetate is being formed in the boiler/column. This is why it continues to be present even after heads removal. (see assumptions 1, 5, 11)
2. Bicarb addition neuralises acetic acid, preventing ethyl acetate formation, distillation of acetic acid, and hence future esterification. (see assumptions 6, 7, 9, 10, 12)
3. Bicarb addition can hydrolyse ethyl acetate, thus decreasing it's quantity (see assumptions 8, 9)
4. There is actually a tiny amount of ethyl acetate about, but it is highly noticable (assumption 3). Using bicarb (as opposed to hydroxides) actually has a rather small effect on the amount of esters in the mix. What it does (primarily) is to prevent further formation, and hence allowing the still to do its job without the moving target of continually increasing ester concentrations in the boiler.
5. Based on this lot, adding bicarb at the start of the final distillation is sufficient, as neutralisation of acetic acid is instantaneous.
Why? Yeast and yeast nutrient both contain lots of ammonium salts (like DAP), which are very stable under acidic conditions, but which release lots of ammonia as the approach neutral conditions. Actually, you will start getting ammonia at about pH 5! Ammonia gas is very corrosive to copper, and you will find your condenser coil packed up with blue crystals after such a run (and blue alcohol too !)
Schweitzer's reagent is cuprammonium hydroxide, and is formed when copper hydroxide dissolves in a dilute ammonia solution). It is a deep blue colour, and is particularly known for its ability to dissolve cotton. The chemist who first discovered this property was Eduard Mathias Schweizer (1818 -1860), so it seems that it should really be called Schweizer's reagent.
It forms in stills when ammonia released from alkaline washes (nitrogen source may be plant material or yeasts) reacts with copper hydroxide formed by the action of steam on copper oxides coating the inside of copper columns or components. It may be avoided by ensuring that the liquid in the boiler is slightly acid (pH less than 7).
Boiling ChipsIf you're heating your still over an external heat source, then you should have a couple of boiling chips inside it to help break the boil. These are any rough-surfaced, inert object - like bits of broken pottery (unglazed so as to avoid lead based glazes), broken glass, or even a couple of marbles.
The rough surface acts as a site where the bubbles can start to form easier. If your pot is nice and smooth on the inside, then its difficult for the bubbles to form, and you can end up super-heating the liquid. When it does boil, it might be quite violent, and give surges of vapour up the column, ruining that nice equilibrium you're trying to create. Boiling chips, although making the job a little noisier (rattle like hell!), do help give a smoother simmer.
Cloudy SpiritSometimes your spirit may turn a bit cloudy when its been left by itself. This can be due to a couple of reasons ..
Sometimes the spirit may get a slight blue tinge to it. This is usually a sign that you've used too much nutrient in the wash. Mike explains ...
In fact, I've learned that it is just the opposite! Acid washes do not corrode the condenser (unless, perhaps, they've been allowed to sit far to long and have gone acetic), but neutral to alkaline ones DO. Heating an ALKALINE wash, particularly one with lots of nitrogen-containing compounds that have been put in as nutrients, liberates ammonia, which corrodes the heck out of reflux coils and dyes the distillate a distinct greenish blue.
The Upshot: if the WASH is turning blue, it's probably due to acid wash corroding a copper sheathed element or a copper boiler, but if the collected DISTILLATE is blue, (and probably ammoniacal, but not always), the wash should be acidified!
Turbos contain a lot of nitrogen-containing compounds, and at neutral to high pH, these can liberate free ammonia. At low pH, they are bound up with the acid as salts, and do not liberate ammonia. So, by adding nutrients to an already nutrient rich turbo, you can inadvertently push the mix over the line and get ammonia with your distillate.
Using a Pot StillA pot still is fairly straight forward to use. Turn it on. Once the temperature is up to about 60 °C turn on the cooling water to the condensor. Make sure you throw away the first 100 mL per 20L wash, as this will contain any methanol that might be present. Segregate the distillate into 500 mL lots as it comes off. Only keep (for drinking) that which doesn't contain fusels (smell off) - probably below about 92 ° C, however you should keep distilling past here, untill about 96 ° C, as this fraction, although high in tails and not good for drinking this time, can be added back to the next wash and cleaned up OK then.
Graham describes using his ...
I normally cut my runs when the alcohol drops to about 40%. The heat put in compared to what I get isn't worth it.
>How do you judge the "cut points" for foreshots and feints ?
Ah the terms they use for this "firsts and lasts", "Heads, Hearts and tails". for those who dont know, The flavour of any spirit come from a wealth of compounds, alderhydes, amy alcohols (fusal oils), esters, acids and even methanol. The desirable ones are commonly called congeners. The art of any distiller is knowing when to start collecting the heart and stop it again. Start it too late and stop it too early, and you collect mostly pure ethanol and no flavours. Start too early and stop too late, well you make something that will have a lot of flavour, but will give you ripper hangovers, could even kill you.
The art is to collect enough of the congeners in the last of the head and beginning of the tails to get the flavours, but not enough to make it undrinkable. You do this by watching the thermometer at the top of the still. When the firsts start, it will sit at 65C-70C. This is mostly methanol coming off. This you dont want. Then it will suddenly rise as all the methanol is removed. It will rise to 78-low 80s (depending on heat and what you want).
This is the heart. Now for a good rum, you want lots of flavour (and the headache with it) so you start collecting as soon as it starts to rise. For a whiskey, I tend to collect when the temperature hits 78C. For clean spirits, I wait till the temperature stabilises. The same occurs at the tails. The temperature suddenly heads for the 90's, and thats agian when you decide to cut it as the higher alcohol start to evaporate and collect. This I do by the the highly accurate method of tasting it.
The Omnipresent Mecakyrios advises how he uses a Doubler with a pot still ...
I would fill the boiler to the normal capacity with my wash. I would fill the doubler 1/3 full with wash as well (sometimes I would put in 50/50 wash and neutral spirit in the doubler). I would run my batch. If I still had another run to do that day I would throw our the spent wash in the boiler, fill the boiler with the new wash to be ran, add the liquid that was in the doubler into the boiler with the new wash, fill the doubler with new wash adding to it the tails of the run that I had just finished, and start the run. I keep doing this until I have no more wash to be ran.
At the end of a day's run, I toss out the boiler and doubler liquids. I keep the tails until my next run. Sometimes, if I have patience enough, I will store the distillates of that days run and add them to a previous run's distillate. In other words, let's say that a month ago I did a run and had collected one unit of distillate from the first run of the day, a second unit from the second run of the day and a third unit from the last run of the day. I will combine all of the units together and mix them up real good. I will then take one unit worth of distillate and set it aside. I will take the remaining distillate and put it into a container and label it with the date. The unit that I had put aside is for me to drink while I wait for a whole month to go by. Then let's say I did a run today and had collected three units of distillate. I will combine these, put one unit worth aside and add the rest to last months run. I will continue to do this until I have a month of down time.
During the down time I clean out the still real good and take the bottle of several months worth of distillate and draw of one unit worth for me to drink, the rest of the several month collection is bottled, sealed, labeled and stored away and forget about it until a special occasion happens when a good aged product is called for.
My still is 6l, I usualy put in a 3l wash ( or 1.5l if it's a lumpy fruit wash ), I discard the first 10ml and then put a jug under the outlet, every 50ml I swap jugs and transfer the spirit to a bottle. I sit there with a shot glass, a spit bucket and a glass of water and every so often I collect a few drops from the outlet and taste. It's up to my tongue where I stop collecting.
Big tip - before mixing fractions try mixing a small quantity separately - some fo the later fractions have a bad habit of suddenly clouding when added to the earlier.
My final ABV - using a set of volumetrics in the lab is 60% on the first run, for Eau de vie I don't often do a second run but sometimes I will add all fractions from previous runs to last was and collect that with a lot of care.
If it's relevant my lyne arm is 1m long and has a slight upward incline.
I take my 5 gallon batch of mash/wine, and I fill 10, one gallon milk jugs half-full (one half gallon being 2 quarts) of the liquid. I then put these jugs into the freezer for two or three days, until they freeze into a solid block of ice. I then set the jugs upside down on a one quart canning jar. The alcohol will drip out as the ice melts (don't add any heat- let it go at it's own pace). When the one quart jar is full, I put the liquid (in the jar) into my carboy to let the yeast, etc settle out overnight. The block of ice in the jug is washed down the drain with hot water- there is no alcohol in it. Since the alcohol melts faster than the water, it tends to come out first- so instead of 5 gallons of 7-10% mash/wine, I now have 2.5 gallons of 17-20% mash/wine.
It takes no real effort on my part, but gives the same results as a beer stripping run, roughly doubling the alcohol content by cutting the volume in half. It doesn't stale the flavor like distilling can do at all, quite the contrary, it makes it stronger- this same method is used by some winemakers to make fortified wines at home (like port, sherry, etc.), without using distilled spirits. By cutting the volume in half, and doing it by freezing, not distilling, the flavor is preserved a little better, but the alcohol is high enough that a spirit run can be done. It typically takes one to four hours for the quart jars to fill up- it depends on the starting alcohol content- the lower it was at the start the longer it takes to melt out. It saves a lot of time for me, since I have a lot of freezer space.
When I make my malt whiskey, it used to always foam over in the still- by freezing it like this, then diluting the mash back to 5 gallons with water when I put it in the still- the starches causing my foaming problem have been diluted to the point that they can't lace together and foam up in the still. In the potstill, it just saves me 4 hours of work on an extra run. While the stuff is melting, I check my e-mail, work out, read, or whatever I feel like doing that I can't do when running a still, because that requires all my attention.
I usually run it through at least twice and usually three times to get it as refined as possible. No hint of fusel oils at all, as proved by drinking it in massive quantities all one night with absolutely no hang over the next day. I use a propane camp stove to heat the pot as i find it has greater control capabilities.
I have been trying the hyper yeast from Gert Strand, am not impressed with the results, a little too yeasty in the aftertaste, could be something i've done wrong, but tried three batches with basically the same result. I will probably go back to using my old receipe for base whiskey, 2 cans of frozen orange juice, 2pkts champagne yeast, 4kilos white sugar and water to 25 litres; you can then feed the resulting mash as the gravity drops till saturation.
Tried a rum with fancy molasses 1 gallon 2 yeast water to specific gravity that appeals to you and your yeast, had a friend that works for a distillery, he went on a junket to pourto rico, where they have a distillery, he brought back a bottle of their finest, we did a blind taste test and couldnt tell the difference. Of course after several more taste tests, we couldnt have told the difference from dish water, needless to say I didnt let him drive home as he would have blown the ass off a breathalizer.
In terms of the modern reflux column which, even in our amateur hands, can consistently deliver 95-96% pure spirit, the pot still is very inefficient. It delivers only impure mixtures of ethanol, water, and congeners. For that reason one usually double-distills (redistill) the wash - the first time delivering a distillate at ca. 30-40% abv, and when re-distilled raises this to 70-80%abv. Even then the product still contains congeners in addition to the ethanol. However, it are the congeners that impart the flavour of the grain or fruit. And most of these come from the 'tails'. As Ian Smiley puts it, the tails 'bleed' into the middle cut. While the reflux still can produce mind-stomping purity, the pot still must be run with a sense of art.
> Why double distill? The abv would be right on from the first run (35-40%). Is the first run still too harsh to drink?
One double distils to increase the alcohol content, but more so to concentrate the congeners. Note that in pot stilling the focus is on the 'also-rans', the congeners, and not on the alcohol!! The pot still is all about flavour. The first distillate from say a malt / barley run is insipid, but better than the wash was. However, when that distillate is run through again, and more water is discarded, the congeners are further concentrated. The final taste of a single malt whisky is likely about 70% congeners from the wash, and 30% from the cask wood.
The art lies in knowing how much of the congeners to allow into the middle cut.
Cut-off point? That depends on one's sense of taste, and on what sort of whisky or brandy one wants - highly flavourful, just right, or overwhelming. Ian Smiley devotes several fine pages on this point - viz. pp. 72-74. (Making Pure Corn Whiskey. 1999. ISBN 0-9686292-0-2; http://www.home-distilling.com/) . It is a matter of deciding how much of the tails one collects into that middle run.
>What are your feelings on the notion of increasing the sugar content in a berry based wash by adding sugar ?
I suppose that depends on which is desired - fruit flavour or ethanol strength. One could argue that blended scotch whisky is in fact sugar based, as a blended whisky is a mix of single malt whisky and grain alcohol, where the latter is highly purified grain distillate, devoid of grain taste. Just the opposite, in eastern Europe slivovitz (plum eau de vie) is double distilled from soft ripened plums, often weeks old, left to ferment in tubs with natural yeasts. Now, that distillate should be plenty flavourfull but in some regions more ripened plums are added to the distillate to further enhance the plum flavour.For me, it is all about flavour, so I go for the fruit or grain.
I do a stripping run first. Reflux down as low as possible. I have a still spirits still which I have modified into a compound still. I have the original head and a second lid so that I can use this as a basic pot still. The short column originally had a cooling jacket and a marble. I have disconnected the jacket and removed the marble.
Final cut point is a matter of taste and flavour. I am generous with it at this stage since I am going to do a second distillation and can be more picky there.
I don't seperate out any heads from the stripping run. The reason for this is that I then stick it into my compound head, water it down and bring the still to full reflux. I let this stay for an hour, and then take off my heads as normal. Once I have got the heads out of it, I turn the still off and let it cool. Then I run it through the pot still again, taking more care that the final cut point tastes good. Water back to 50% and oak. Voila!
StrippingPot stills can be used to "strip" the wash, prior to a reflux distillation. By passing the wash once through a pot still, it will be increased in purity from say 10-15% up to 40-60%, reducing it in volume by 4/5th. This way, you can strip say 100L of wash down to 20L of semi-clean spirit to then load into the reflux still for a single pass (rather than having to do 5 reflux passes of 20L of wash). This will not only save you plenty of time, but it will also help result in a somewhat cleaner spirit, as any yeast, etc get removed during the stripping run. You could also use a reflux still to do the stripping in, by simply not making it reflux any of the liquid.
When you do your stripping run, it can be beneficial to add some sodium bicarbonate (baking soda) to the first-run alcohol, prior to the second ru n. As explained up in adding salt this will help clean up the taste greatly.
Mike explains the chemistry ...
Taking the last first, if an aqueous solution of sodium bicarbonate (baking soda) is warmed then it starts to decompose with the formation of sodium carbonate, water and carbon dioxide, the decomposition being complete on boiling. Good grief . that's why Granny uses it for her soda bread. The carbon dioxide leavens it! The reaction is: 2Na.HCO3 = Na2.CO3 + H2.CO3 [and H2CO3 -> CO2 + H20] [water + sodium bicarbonate = sodium carbonate + carbonic acid + lye] and the carbonic acid further disassociates to form carbon dioxide and water, particularly when heated [H2.CO3 = CO2 + H20]. Add tartaric acid and you have a quicker reaction with more CO2, and you then call the stuff baking powder which Granny uses to make her nice light scones.
Working back a bit, where did all that ethyl acetate come from? Well, we all know about vinegar (acetic acid, a fatty acid), and that a 'dirty' ferment or a bruiser of a fast yeast can result in quite a bit of that. What may not be generally known is that fatty acids react with alcohols to form esters, and acetic acid and ethanol get together to form ethyl acetate which is . you've guessed it . an ester with the composition C2H5.COOH
So now we add baking soda (sodium bicarbonate) to try turn all that that ethyl acetate, which started out as vinegar, into booze. Why bicarb? Well, although it's an acid salt of carbonic acid, it turns out that in an aqueous solution it's alkaline, due to hydrolysis. The Na.HCO3 disassociates to form Na+ and HCO3- ions, and the H+ ions from the water (H.OH) combine with the HCO3- ions to form undisassociated carbonic acid H2CO3. This leaves heaps of Na+ and OH- (hydroxyl) ions mooching around . and those two together spell sodium hydroxide . a strong base. So what happens when these ions bump into ethyl acetate? The sodium ion grabs hold of the COOH bit to form NA.COOH, sodium acetate, and the hydroxyl ion grabs the C2H5 bit to form good old C2H5.OH, booze!
But hang around a bit! What happens to all that sodium carbonate [NaCO3] that was left behind when the baking soda disassociated? Well, it's quite handy because it too disassociates in an aqueous solution to form more carbonic acid and lye, with an excess of hydroxyl ions floating around [Na.CO3 + 2H.OH = H2CO3 + Na.OH + 2OH-]. Now this deals to any excess acidity you might have, the OH- ions grabbing acid H+ ions to form water. Not only do you get more Na.OH for conversion of acetate to booze, but the solution is buffered to a pH of just over neutral 7.
This gives us the clue that oyster shells or chalk [CaCO3] will do the same thing, and will also work to convert ethyl acetate to booze as the stuff disassociates in the same way [Ca.CO3 + 2.H.OH = H2CO3 +Ca.OH + 2OH-]. In this case it's the Ca+ ion that grabs the COOH bit of the ethyl acetate to form calcium acetate [Ca.COOH] and the hydroxyl ion grabs the C2H5 bit to form what we're after . C2H5.OH, booze. The only thing to consider is the relative solubility of baking soda compared to chalk, but those who use hard water to dilute their strippate may be on a winner!
Now those who haven't fallen asleep already will be wondering why they can't just add a good dose of lye (Na.OH) to the brew and be done with it. Snag is, how do you know when enough is enough? Put too much in and you have a surplus of lye in the brew, and nothing to counter that. Keeps the boiler clean, but corrodes the hell out of it. In contrast, by using baking soda or oyster shells/chalk you end up with sodium/calcium acetate, and that is also a pretty good buffer, like the sodium/calcium carbonates.
Much too has been made about how long this treatment takes. What has to be borne in mind is that it is a relatively slow reaction compared with inorganic reactions that go at the speed of zip. So all it comes down to is how impatient you are. Some might argue that heating the solution up will speed the reaction as it will hasten the formation of the carbonate. Well, they may have a point . up to a degree. However, just remember what happens when you boil hard water . the carbonates are precipitated out, as anyone in a hard water district will know from scaled pipes and kettles. Chuck the bicarb or shells/chalk in and boil immediately and you will get very little conversion, leave it for a couple of months and can be sure you've done the job fully. Similarly, chuck citric acid in and you will stop the reaction dead in its tracks as it will neutralise the bicarb/carbonate treated solution (each citric acid molecule has no less than three H+ ions to give up . hence its use in scented "bath bombs" to get all that luxurious, soft water that keeps the bubble bath foaming). My money is in listening to those who have achieved very good conversion of the bulk if the ethyl acetate by giving it a week or so to work before distilling.
Mike lists three advantages for stripping runs:
a) Rapidly boiling the wash and condensing everything that is vaporized, without bothering to separate the heads and tails, is an easy way of reducing the volume of liquid you will subsequently process with care, saving a lot of time overall
b) The reduced volume of liquid you get from a stripping run is clear of all solids, salts and dissolved gases.
c) The liquid you get has a very much higher concentration of volatiles, enabling far better separation in the subsequent rectification run as you start out in the middle of the equilibrium chart (the one that plots the concentration of volatiles in the vapor against their concentration in the liquid the vapor came from ... the one that looks like a fat cigar leaning at 45 degrees)
In essence, it is much easier to clean a muddy kid after a football game if you first give the brat a quick hose-down to get rid of most of the mud, and then then shove him in a clean, hot bath with a cake of soap with instructions to wash behind his ears, than it is to try and do it all in a bath full of muddy water. Whiskey distillers, who have to tackle the difficult job of dealing with a mash full of solids, first concentrate on separating the low wines from the mash in a big still, where the only problem is to prevent burning, and then move on to a smaller still where they concentrate on getting the right cut from the clean low wines. Experience has taught them that this is a very effective and efficient procedure that results in a much better product than if they tried to do the whole job in one go. It is definitely well worthwhile.
DP writes more on this, and how it can be used to clear up heads ...
Esters are flavour compounds responsible for many of the characteristic tastes we know very well:
Propyl acetate (Pears)
Octyl acetate (Oranges)
Isoamyl acetate (Banana)
Ethyl butyrate (Pineapple)
Butyl acetate (Apple)
Methyl trans-cinnamate (Strawberry)
(See http://www.leffingwell.com/esters.htm. There are many others and a web search will turn up many more if you're interested.)
Esters are the product of a reaction between an organic acid and an alcohol. Read the back of a wine bottle you'll see wine described as tasting of all sorts of different fruit (except grapes, of course because any fool can do that). Yeast, by its very nature, produces a range of organic acids and a range of alcohols during the fermentation process. These combine to form a range of esters responsible (along with other chemicals) for the flavours in wine that aren't in the original grape juice. This is where the interests of a winemaker differ from someone trying to make clean neutral spirits - winemakers see ester formation as desirable. Yeast makers even advertise their yeasts on how good they are at producing damn esters.
The problem with esters is that a little goes such a long way. Most have detection thresholds measured in parts per billion (ppb). Ethyl butyrate – the fruity pineapple ester listed above - has an odour detection threshold in water of 1ppb. As a comparison, ethanol in air has an odour detection threshold of about 50 parts per million (ppm). In other words, it's odour is 50,000 times more powerful than ethanol. For those of you obsessed by percentages, your distillate could be 99.9999999% ethyl butyrate free and you'd still be able to smell the damn stuff. Great if that's what you want, bad if you don't.
The ester of the most relevance to home distilling is ethyl acetate. Ethanol oxidises to form acetic acid. Acetic acid and ethanol react to form ethyl acetate. It's no real surprise that you are going to end up with some of this stuff in your brew - yeast puts it there. The good news is its odour detection level is a relatively high for an ester at 5000 ppb (or 0.0005%); the bad news is it has a nasty solvent-like smell you're probably already familiar with. And there's more bad news…
By itself, it boils at 77 degrees, which is pretty close to the boiling point of ethanol. It forms azeotropes with both ethanol and water, and another when all three of them are mixed together (although all at mixture ratios you are never likely to see). I have heard many claims that ethyl acetate can be effectively removed by a still. It's more correct to say that using a still, a good operator can separate the ethanol that contains ethyl acetate (the heads, etc) from the ethanol that doesn't. To me this is not "effective" as the heads contain far more ethanol than anything else and I make ethanol to drink and not tip down the drain. As I said, stills are great for separating alcohol from water, but that doesn't make them the best tool for every job. Removing ester-related flavours with a still has all the finesse of opening walnuts with a sledgehammer. The secret is knowing your enemy:
Food is acidic. Just about everything we eat has a pH less than 7 (See http://www.phsciences.com/about_ph/ph_foods.asp). Acid inhibits bacteria growth and is the environment in which esters are formed. The chemical reaction that produces esters, however, can be reversed – when taken out of an acidic environment esters hydrolise back into the acid and alcohol from which they were originally formed. This is why food acids are so often added to preserved food – it helps preserve the flavour as well as preventing spoilage.
Ethyl acetate is formed during fermentation. After distillation it's no longer in and acidic environment and starts to decompose back to ethanol and acetic acid. Acetic acid gives vinegar its characteristic taste and although pungent, it's far less detectable than ethyl acetate – not great, but less bad. As decompostion produces an acid it tends to slow the rate of further decomposition, but eventually it does happen. If you have the time, people have been getting good results from sticking alcohol in barrels and waiting a decade.
If you don't have the time then don't worry lots of things can be used to speed up the process: agitation/aeration, light (called photodecomposition) do this. The resulting acetic acid has a boiling point of 118 degrees C so it's much easier than ethyl acetate to separate from ethanol in a subsequent distillation. If you add some mild alkali (sodium bicarbonate, sodium carbonate or calcium carbonate) into the mix you can speed up the decomposition time and also precipitate out the acetic acid. By adding a couple of teaspoons of sodium bicarb to your nastiest smelling heads and aerating them with an aquarium pump and air-stone for a week you will end up with something that smells OK. Not quite good enough to drink, but more than good enough to redistil.
This is the real way to solve the ethyl acetate problem – not by pouring your (mostly ethanol) heads down the drain. You get to recover all the ethanol that the ethyl acetate had spoiled and (the really elegant part) some of the ethyl acetate is actually turned back into ethanol. The point to remember is the same process will reduce all ester-related flavours, and not just ethyl acetate, including the ones that exist in immeasurable, but still detectable quantities. You don't even need to know what esters they are!! They all breakdown into different components, which you may not particularly want either but will all have less impact on overall flavour than the original ester.
Once I learned this I changed my process to double distil everything. After the first distillation I throw in some sodium carbonate and aerate for a week before distilling again. I don't separate the heads from the second distillation because there's nothing to separate and the result doesn't need carbon filtration. More importantly, nothing I boil off ever goes down the drain - not a single drop. My end-to- end efficiency from sugar to drinkable spirit is 90% with the cost of consumables and wastage very low. Plenty depends on your ingredients, equipment and process, but you get the basic idea.
This is a free type translation/interpretation of a freely available material found on web pages dedicated to production of alcohol at home. There are no claims of any kind for this data.
The first chemical reaction of saponification binds fusel oils and makes it insoluble. In order for this reaction to work, alcohol must be tested for pH. If reaction shows that home made alcohol does contain dissolved acids then regular baking soda should neutralize the reaction. The proportion is 5g~8g of baking soda per each liter of alcohol.
After adding baking soda and stirring it well, potassium permanganate is added. Potassium permanganate should be dissolved in small quantity of clean water beforehand. The ratio is 2g of potassium permanganate dissolved in 50 mL of clean water per each liter of home made alcohol. The mix of alcohol, baking soda and potassium permanganate is stirred well and left alone for 15~20 minutes for reaction to finish.
After this stage is complete, additional baking soda is added to the mix in the same proportion as above, stirred and left alone for 8~12 hours for precipitation of solids.
Next day any sediment is filtered and alcohol goes through the second distillation. This method of removing fusel oils is rather efficient and removes up to 95% of its content.
After the second distillation, home made alcohol is slowly filtered through activated charcoal.
Double Distilling for Whiskey etcHere we try to replicate the traditional style as used in commercial distilleries world wide. See Making Whiskey - A Personal Experience by Roger Dowker for a detailed description of the commercial process, including when the various cut-off points are.
The trick to this appears to be the stuff legends are made of, and closely guarded by those who know. It's the matter of how much of the first condensate, or foreshots, to discard and how much of the middle cut to keep before discarding the last runnings, or feints.
Steve writes that its difficult to do this by temperature alone, nor to have a single set of guidelines ...
For the various %'s at which to do the "cut", Donald advises to use a great hydrometer with 0.5% or greater calibrations for best results, and suggests ...
When about 2/3 - 3/4 of the way through the middle run, and approaching these cut points, start collecting the spirits in smaller collection containers, and smell each of them seperately. The flavour will change from that of the neutral spirit, to more and more of the flavour coming through. This will intensify, but then start to become bitter. You need to work out when to make your "cut" during this period, but do so before it gets to the bitter stage. After making the cut, keep collecting (seperately) the feints up to about 92 °C, and add these to future runs.
For a reasonable whisky without the long term maturation try this :
Load the still with the low wines and set it going.
You can now take the 5 litres, flavour it a little bit, put it in a small keg or flavour it with some oak essence. If kegging cut with water to around 40% or the angel's share will get too much. Don't charcoal filter or polish this spirit, as all the tasty bits you've just worked so hard to obtain will go too.
In theory, lets say I was the distiller at Ardberg with one wash still and one spirit still, I would run all the spirit out of the washstill as low wines, load this into the spirit still and run foreshots, high wines, with a cut at betwixt 65/60% then the rest as feints down to X %. The feints could then go back to the wash still or spirit still for the next batch. If I were at Ardberg, I would probably run them back to the wash still.
In order to get congeners, as opposed to a neutral profile it is important not to have a definitive reflux device in the steam path - enough refluxing will occur within the headroom, the "roof" of the still body, the lyne arm or equivalent. Make sure the still is only filled to about the three quarter mark.
As the weather becomes hotter and hotter in the southern hemisphere pot distillers put less wash in the body of the vessel thereby allowing more head for particulates of the solid variety to not be entrained [carried over] into the distillate. If you have variable control throttle back a bit.
Jack adds regarding the tossing of heads...
I also learned that these "middle cut" numbers are good for any volume, and any still- I have made a corn whiskey and have "made the cut" according to Ian Smiley's numbers- but I did this with an ice-water-wok still, and only 2-liters of freeze-concentrated mash (equal to 4 liters unfrozen). It comes out to:
all adding up to the 750ml bottle I normally get of pretty rough stuff out of this still. Just by applying the middle cut numbers, I get just over half as much- but it is a LOT better.
By the way, even the Scotch distilleries are now admitting that yeast strain makes a difference in the spirits' final flavor. They figured this out after a couple of research chemists at a distillery made a batch, then filtered ALL the yeast out, and distilled it. After comparing the resulting spirit with regular (unfiltered mash) spirit, they found (under liquid chromatography), that the yeast has a BIG influence on flavor due to the long chain fatty acid esters that are found in yeast do distill over into the spirit- this is, in fact, the cause of cloudiness in spirit thats been run through a potstill only once, not the heavy alcohols as was once thought.
Using a Water Distiller as a Pot StillIf you want, you can use the commercial water distillers as pot stills, though they're not really the best for it. But it can be done. Make sure that you turn it off before collecting the tails - dont just let it distill all the brew you put in there, or else you'll simply end up collecting it all again. (The Kenmore still is a water purification unit marketed by Sears. It is complete and self-contained, with its own carbon filter. The brief description can be found at http://www.sears.com)
Steve explains his technique :
I'm not sure how accurate this method is, but what I do is discard the first 50 mls of heads.. Then I collect enough total liquid such that I stop when my spirit hydrometer indicates it has reached about 48%. Probably could go down to 45% but I don't want much tails at all so I stop a bit early at around 48%. Basically I collected the first 500 ml, and then the next 50 ml thereafter and found that the tails and taste started to get bad at about 850 ml, so I stop at around 600 ml, which in this case came out to be around 48%. Not exactly precise, and possibly leaving some good stuff behind, and may differ depending on the alcohol percentage of what I'm distilling, but on the whole once you've got it figured out for the first time for a particular mash it is totally painless to use. Since the quantity of fluid I put in there is also very known, it is easy to get it down to a science and just use a timer.. Like 35 minutes to the point where the heads start coming out of the distiller, and then 47 minutes of collecting the spirit, which then yields a known quantity of liquid. After you figure this out the process becomes very easy and reproducable.
There are a few different models of having different sizes so these numbers won't be the same for every Sears/Kenmore water distiller.
Since the quantity of liquid is small, and you're not using an open flame, it's probably a bit safer too than operating some stills.
Still Spirits also has some instructions on how to use it.. Called distilling with the Sears Water Purifier. They just suggest to collect certain quantities of liquid based on using their known alcohol percentages of their yeast/nutrient/sugar combinations.http://www.stillspirits.com/instructions.htm
The product seems fine. It may not be as excellent as the 90+% you get with a more extensive set up, but it works for me. I've produced a drinkable Brandy from wine, I've added essences to sugar washes with good result, and even done my own alchol extractions creating a nice Ouzo/Anisette. It does take many runs to do a 5Gallon batch, but it requires little monitoring once you get the timing down.
A couple of pointers for those interested:
Watch the amount of wash you try to run. My unit is supposed to take 3 quarts, but the most I can really do is closer to 2.5 because of boilovers. The amount of residual sugar in your wash has a great effect. I tried to run a failed beer, and it would boil over (boil up into the condeser) at any thing over 1quart! I ended up dumping 8 gallons of beer into the garden...)
I added a small amount of copper to the vapor path by attaching a copper pipe "elbow" stuffed with copper scrubber to the rubber/vinyl inlet hose on the lid of the unit. I don't know if it helps, but I figure it can't hurt.
Using a Reflux StillThe alcohol coming off a reflux still will be more distinctive / occur in steps. Rather than a gradual increase in temperature over the coarse of the run, it will get up to certain temperatures (near those listed above for pure fractions), then tend to sit there. The alcohol coming off will be of a fairly steady purity right through, only dropping off late towards the end. You'll probably finish a reflux run at a lower temperature (say 92-94 ° C) than a pot still (say 96 ° C.
For example, my StillSpirits 20L reflux still takes about 1 hour to heat up, then once it gets to about 40 ° C, it then heats up pretty quick to 65-70 ° C. It will then sit there for around 5 minutes, and the first liquid (distillate) starts condensing. After about 5 mL of distillate have collected, the temperature then starts climbing again, up to 80-90 ° C.(Note that these temperatures aren't exactly as in the table above. The water & ethanol form an mixture that boils at a higher temperature - as shown in the graph way back in the Theory section). It will then sit there for the next 2.5-3 hours, and I collect the distillate at the rate of approx 1L/hour. (with my improved reflux still, it now sits steady on 78.2-78.4C for most of this period - eg 95% purity) Slowly towards the end of this period, the temperature slowly starts increasing up towards 90-94 ° C. By this stage, my hydrometer shows me that the alcohol is only about 40%, and I've usually had enough, so I then turn it off. Total time 4 hours. (with the new reflux still, I finish collecting at around 82C, as past there it deteriorates fast towards the rubbish - still 4 hours though)
Likewise, finish distilling at 92-94 ° C, as you've basically got all the easy ethanol, and you're starting to collect the higher ends, heavy in fusel oils (the wet cardboard smell).
Rob has the following advice running a reflux still :
To make it easier to achieve maximum purity I strip the beer first and I remove the first 100 ml to be sure the methanol is out. I stop distilling when the temperature reaches 95 Celsius regardless of the %.
The low wines I have now are approx. 55% and I dilute this to 40% max. for the fractioning distillation. I slowly bring the low wines to the boil and keep the cooling water running at a high rate for maximum reflux at the top of the column. After a while I tune the cooling water until I get a steady drip from the condenser outlet; I keep the boiler at the lowest boiling rate possible.
Every 100 ml I check the % and I put a few ml in a noser (glass) and I add the same amount of water; as soon as I detect a distinct smell of wet cardboard, I know I have to stop collecting the middle cut; the alcohol that comes after this point (not much if the fractioning was going well) is collected, and after a series of distillations I fill the boiler with these faints to collect the remaining ethanol. When checking the alcohol for wet cardboard smell, it is important to dilute the alcohol first to 30-40%, because the undiluted alcohol will not release the smell, and you will notice it too late when you are preparing your wodka, liqueur etc...
You will notice, that the off smell will start to occur as soon as the temperature in the top of the column starts tending to rise above 78,5 celsius or the drip from the outlet starts to diminish and you need to increase the heat to keep the boiler going. Also the % goes down to less than say 92%. Don't waste your vodka now by trying to collect that little bit more !!! After a few runs, you'll get the hang of it; there is nothing better than experience.
Using a Fractionating StillThe difference here is the need to really equilibriate the column at the start of the run, so that the methanol gets to accumulate at the top of the column, and to get all the packing in the column up to its equilibrium temperature so that it will work its best. This can take from 1-4 hours.
To get a fractionating still to work at its best also requires quite a high reflux ratio - returning 8-12 times back to the column vs that which is kept. To do this means knowing what the total rate is, then trimming the offtake valve to only take a portion of it. Do this by opening the valve fully and measuring how fast it is coming out, then closing down to only take what you should. Once you know this setting (say 1 drip per second), it will be the same for future runs.
Using the collection calculator back up the page, you know how much alcohol you have to collect, thus it is easy enough to work out how long its going to take. You may figure that its not worth waiting quite so long, just to gain a couple of 0.? % improvement in purity. Experiment to find a reflux ratio that still gives you a suitable purity, without having to wait forever.
I control my still only by adjusting the reflux ratio. It will happily sit between 78.2 C and 78.4 C for most of the run with a low reflux ratio, but towards the end, the reflux ratio will need increasing more and more to hold it there. As this happens, change the receiving container, and keep the tails seperate.
For me I let the still equalize in total reflux for 2 hours and then draw off the foreshots and then let it equalize for another 1/2 hour. Then I draw off the heads until I cant detect a foul smell. These I save and add to a container labled "faints". Then I distill the middle run and a portion of the tails. I run this phase until I reach 75 pct ABV. These are saved in my 'product' containers. Then everything else is distilled out until 65 pct and placed into the feints container. Then I distill everything else out of the wash that I can get. I stop when still head temps reach 205 F (96C) or so. Everything in this portion goes into a container labled 'redistill'. If you 'throw everything away' then you will be sending perfectly good ethanol down the drain. It might not be beverage quality right now, but it will be excellant stock to make a clear vodka from.
Rum from a Reflux StillSee the different recipes etc in the sugar based washes page.
Make the wash from diluted molasses. Arroyo recommends to split up the fractions out of a reflux still, and then recombine them. The fractions are collected as per ..
I don't get that fancy with my rum. I first equilibriate the column, and remove approx 50 mL of foreshots, one drip per second. Then I open it up, so that I'm collecting quite fast, and at around 82-84C (rather than my neutral spirits temp of 78C). I'll collect it all together, until the temp rises to about 90C. Anything after that is relegated to tails. I'm after a big hearty flavoured rum, so if you prefer it lighter, don't take it quite as high in final temperature.
Just like whisky, you can keep the feints, and add them to following batches, to improve the flavour you get. Tom explains ...
Foreshots & HeadsWhen making the "flavoured" spirits such as whisky, rums, or schanpps, theres always the question of exactly how much of the heads to keep.
Mike raises some questions ...
After almost a week of searching through the internet and browsing through the local library, I've also learned that although whiskey washes contain methanol, resulting from the use of grain, not one drop of foreshots/heads or feints/tails is ever thrown away, but is instead frugally stored in the 'low wines' vat for inclusion in the next batch. It was also interesting to learn that the decision on when the foreshot/heads 'ended' and the feints/tails 'began' was entirely up to the still master, and that many distilleries included a fair proportion these 'cuts' in the middle run as they contain a lot of flavour compounds that they want in the final product. What also surprised me was how little of the foreshots/heads were diverted to the low wines vat, some distilleries starting to collect the main body only 10 to 20 minutes into a run. Considering the size of their batches, that's very little indeed! Perhaps they rely on long periods of maturation to modify the compounds they include?
The way the still master judges when the foreshots/heads 'finish' and the feints/tails 'begin was also interesting, as it is all done without the benefit of measuring the temperature of the vapor or being able to smell the product. It's all done begind glass in the still safe, and the traditional methods depend on measuring the density of the product (correcting for temperature of the liquid) and what is termed a 'misting' test. Many distilleries now use more sophisticated methods, but these two tests are still widely used. The temperature corrected density seems fairly obvious, but the 'misting' test was new to me, so I had high hopes that perhaps here was a method we could use. Essentially, the 'misting' test involves mixing a sample of the product with distilled water. The presence of foreshots/heads or feints/tails is indicated by the mixture taking on a faint milky cloudiness. Sadly, when I tried it on some heads and tails that I had set aside, I could detect no 'misting' whatsoever, so I reckon that it must be characteristic of whiskey washes that may contain much higher proportions of oils than we encounter with sugar washes. Any thoughts anyone?
Now, I'm NOT suggesting for one moment that anyone drinks either heads or tails! However, we may have been throwing away a lot of good ethanol when pouring the heads down the sink. Whether those first heads contain methanol or not (depending on the ingredients of the wash), it is apparent that they contain a very high percentage of ethanol. If, instead, we set them aside and added both heads and tails to the next batch – all of them, as the whiskey distilleries do – then we would be in no danger of including them in the results of that next batch as we would again set aside the heads and tails of that. The obvious question can be asked ... would this not mean that the amount of 'nasties' builds up over time as they are repeatedly added to successive batches? Logically, the answer must be 'yes', but this doesn't seem to worry the whiskey distillers, and they are dealing with much bigger quantities than we are.
As for determining when to start or stop collecting the main body of a run, I believe that the methods we have been using are probably the best there are … measuring the temperature of the vapor and using our sense of smell. They may well be better than the traditional methods used in whiskey distilleries! There is certainly a discernible difference between what we have been calling 'foreshots' and 'heads' … the very first part of the heads is markedly more volatile, so the change to the main body of heads is easily detected by monitoring the vapor temperature. Equally, the slower change in temperature as the main run starts is fairly easily seen if you have a good thermometer in the right place in the column.
Distilling WaterDo you just want to use your still to make some nice clean water ? Zoran advises ...