The principle of distillation is to take the alcohol from a solution and leave behind the water and any other impurities. In the process you will end up with pure alcohol in your collection jug and left behind in the still the water and any other unwanted chemicals from your wash (the pre-distilled liquid containing the alcohol).
Home distillers will typically ferment their own wash because that is the most cost effective and enjoyable way to do things.
Fermenting your own wash
First of all you need to decide on a Turbo Yeast. Some yeasts will produce a stronger Alcohol percentage, around 20%-23%, but with more impurities. Other yeasts will give you a purer wash but at the expense of a lower alcohol percentage, around 14% alcohol.
The equipment needed you'll need a 25 Litre Fermenting Vessel with a tap and Airlock fitted, Thermometer, Hydrometer and a Plastic Mixing Spoon. For ingredients you will need around 6 kilos of Brewing Sugar (a Dextrose Brewing Sugar would be ideal for a faster, clearer fermentation) and some Turbo Finings (this will turn your cloudy black fermented wash into a nice clear solution ready for your still).
Follow the simple instructions provided with the Turbo Yeast, leave for about a week and add the Turbo Finings and leave for another 24 hours. Now that you have 25 litres of a strong alcohol wash its time to purify it in your Air Still.
Distill your wash
Firstly you should read through the manufacturer's instructions and safety manual for your Air Still. Remember to put your ceramic rings into your Air Still first. These will stop super heating from occurring in your Air Still (please read below the more detailed description about the dangers of super heating). Then set up your Collection Jug and active carbon filter attachment (to activate your carbon run under warm water for 45 seconds). Now take 4 litres of your wash into a jug and then pour into your Air Still. You must pour in your solution before turning on your still, never pour your solution into a hot still. Once everything is in turn it on a leave for a couple of hours. It will take about 1 hour for the still to heat up and for the alcohol to start dripping. The first 20ml or so should be discarded as it will contain impurities and bad flavours. The first 700ml will be the best quality so after you've collected this discard whatever is left. Depending on what yeast you've used you may need to dilute it with water. For example if you've used the Triple Still Yeast your 700ml should be approx 60% ABV, adding 350ml of water would make it 40% ABV.
All that's left to do now is to add a flavour essence and leave for a couple of days for the flavourings to bind with your alcohol.
Superheating is when a liquid is heated to higher than the normal boiling temperature, without actually boiling. This can typically occur when the heating takes place in a very smooth vessel, such as a laboratory glass jar or similar. In this state, the liquid is metastable – i.e. it will not boil as long as nothing disturbs it. However, if you add any object or cause the liquid to move, it is likely to break the metastable state and start to boil which will then happen violently.
The reason that this sometimes happens with the Air Still is that some of them are smoother inside than others, due to the manufacturing tolerances. The smoothest ones can sometimes have this issue, for the reasons outlined above. When the first bubbles form, the liquid is above its normal boiling point and there will be an explosive outburst of boiling as the bubbles break the metastable state. This can also happen if you move the Air Still at this stage, or even worse (NEVER DO THIS!), remove the lid to see if it is boiling.
NEVER add these rings to an already heated liquid. If you do, you could trigger boiling which could make boiling liquid explode out of the still, most likely onto your face and hands.
ALWAYS add ceramic rings at the start, then add liquid, close the still and distil as usual. Don’t open the still until it has completely cooled down, as per the manufacturers instructions.
Note: Always check the legal status in your country before distilling alcohol. When distilling alcohol, some countries (including the UK) require a permit to comply with the law.
Watch the Still Spirits video for further info