Distilling: Part 3

January 15, 2010


So, now that you have a wash and it has stopped bubbling, it is ready to distill.  First you need to rack it, which just involves siphoning most of it out to leaving behind the yeast sediment on the bottom.  Then take it and put it in your still.  

A basic potstill is made up of a few parts.  The pot is what sits over the heat source and where you put the wash.  In the wash, ethanol (alcohol) is evaporated before water because ethanol boils at 173°F vs. 212°F for water.  The now gaseous alcohol travels through the lyne arm, which is a narrow metal tube that comes out of the top of the pot and goes to the condensor coil.  The condensor coil is coiled metal tubing that sits in ice or cold water, where the gas is re-condensed back into a liquid.  The liquid then comes out the end as distilled alcohol.

So, now that you have some terminology down, fire up the still (preferably over a gas stove/heater because they are easier to control) and bring the batch to somewhere around 180°F.  After a tense period of waiting and talking about how the still is not working, you should start seeing clear liquid coming out the end of the still.  If you see gas coming out of the end, it means that your condensor coil is either not long enough or not cold enough, and you need to fix it to avoid losing more alcohol.  The liquid that comes out of the still first is called the foreshot, and contains acetone, methanol, various esters and aldehydes, which are mostly toxic and should be tossed.  Methanol is what causes hangovers in small quantities and blindness in large quantities.  The boiling point of acetone is 133°F, and methanol at 150°F, which is why they come out first.  There are online calculators that can tell you how much to toss based on the size of the batch, and I generally just double that amount to toss.  For a 3 gallon batch, I generally toss 50-100ml.

After that, you should be getting alcohol starting around 140 proof that will lower in concentration as you continue.  You can keep everything that comes out after the foreshot, but it is best to shut the still down when you hit a concentration of about 30% alcohol.  Because it is difficult to measure the alcohol content of hard alcohol, we (we=Nirav) developed a useful trick that gives you good ballpark estimate.  While distilling, periodically set a few drops of collected alcohol aside and see if it will light on fire.  If it does not burn, then you are at a point where you should probably stop the still.  You can also calculate beforehand how much waste and how much distillate you should expect, which is another technique to knowing when to stop.  A third technique is to use hydrometers at all stages of fermentation and distillation to calculate when the batch is done.  Here is a useful calculator for this.

The key to pulling out as much alcohol out of your batch as possible is to keep the water from boiling.  This can be done either with a thermometer or by turning down the heat once it gets going (this gives the alcohol more time to evaporate before the water starts boiling).  The amount of alcohol you end up with can vary drastically depending on how well you kept the temperature and how good your batch was.  I have ended up with anywhere from 2 to 5 wine bottles filled with about 100 proof alcohol from a 3 gallon wash of rum.

While distilling, it is sometimes better to keep the different parts of the batch separate.  Because you get different flavors at different times of the distilling process, if you keep the parts of the distillate separate, you can blend them back together at the end based on taste and smell for a more refined product.

Once you have distilled alcohol, you are nearly done.  All you have to do is water it down to taste (or not) and spice it.  Spicing recipes are totally up to personal preference.  It is best to use solid ingredients over ground ones because you don’t end up with solids at the bottom of the rum that you would have to filter out.  For our rum, we like to add one or two cinnamon sticks, two cloves, two oak chips, and a couple of spoonfuls of molasses and let it sit for about a week before taking the spices out.

One Response to “Distilling: Part 3”

  1. Sabina Heger Says:

    Thanks a lot for putting this up, it had been quite handy and showed me a lot.

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