The Still.
So we did some research and found a brew shop that sold all types of stills (pot and Reflux) we then did some research on the difference between the types and makes.
More information on Still types
Basically a pot still is a classic type still where you make a mash from what ever ingredients are going to give you the type of flavored alcohol you want IE. whiskey or dark run, so dark rum would be made from molasses and brown sugar, whiskey would use some kind of grain mash that gets boiled in the pot and you collect the vapor that condenses back in to alcohol normally around 40% to 50% alcohol with a lot of flavor.
A reflux still is different in 2 ways you do not put a mash in a reflux still you use a sugar / yeast wash that just gives you 94% proof alcohol at the end of the process this is due to the second difference which is plates or special packing in the cooling tower allowing fluid to recirculate down the tower thus washing the vapors making them higher % alcohol than a pot still you then water this down to get to the % alcohol you want. This is run through carbon filters to clean out any impurities in the water/alcohol. Reflux stills are normally used for clear spirit drinks, white rum or vodka or you can add flavor with bought flavorings or make some your self.
The process
The process is pretty simple, you put 6KG of Dextrose sugar in a brew tub, you then add 25Lt of water at about 20C - 25C then add a pack of yeast, we use a 3 day yeast but normally leave for 5 or 6 days till it has completely stopped bubbling and has started to settle. You then test the specific gravity of this with a Brewer's hydrometer and if the final specific gravity of 0.990-0.980 is reached it is ready to be distilled.
Depending on how long we have left it we either add finning to clear the wash or we siphon off if it is clear enough. The liquid is then put in to the bottom of the still and we turn it on, the still is just like a big tea urn with a condensing tower stuck on top, the tower is filled with copper and ceramic pieces. you also need a constant cold water supply to cool the vapors back in to a liquid. the still takes about 70 mins to get the wash to the right temprature and then you see the thermometers start to climb, at this point you have to get a constant stream of water going so the liquid coming out of the still is at about 55C but can be between 52C to 58C.
we average about 1Lt of 94% proof alcohol every hour though each hour it does decrease but we normally get about 3.5Lts of 94% proof from a 25Lt wash that has been distilled for 4 1/2 hours, I know this does not sound much but this has to be brought down to a reasonable % by adding water.
The Formula.
So time for that mathematics you did in school.
the calculation is quite simple.
%proof of distilled spirit X amount of distilled spirit / % of alcohol wanted - orig amount of distilled spirit = how much water to add to get required %.
So 94% (percent of distilled spirit) x3.5(amount of distilled spirit) /44 (required strength) -3.5 (minus the original amount of distilled spirit) =3.9lt of water to be added to the distilled spirit, which gives you a total of 7.4Lts of 44% proof Vodka.
Or heres a Calculator:
Filtering
The final mix does have to be filtered through carbon filters to remove an impurities from the water and the brew, the more you filter the cleaner it is, though as a reflux still only uses water sugar and yeast you do not get so many impurities in the brew as is possible if you get it wrong with a pot still. Anyway there are several different filter methods.
You can by a filter system that is 2 X 10Lt bucket that sit on top of each other and have a hole in the bottom of the top bucket and a carbon block, like the type found in water filters, this is screwed up to the hole so the alcohol has to pass through it, thus filtering the alcohol.
The second is the one we prefer which uses 2 types of active carbon and seems to filter the alcohol very well.
This method uses a 10Lt bucket with a tap, attached to the tap is a length of plastic pipe going to an in-line filter canister. So we add about 500grams of very fine active carbon dust to the watered down spirit in the bucket (first time when you do this your heart sinks as the fluid goes like squid ink and you think "oh shit that will never go clear again"), this is left to sit for 24-48 hours allowing the carbon to pull particles to the bottom of the bucket, we then put a small filter paper disk at the bottom of the in-line filter and pack with a rougher carbon and turn on the tap, at this point we also slightly stir the alcohol to mix up some of the finer carbon so that it gets caught in the in-line filter and fills any gaps and also make for a high filter. At first a small amount of the fluid that comes out is still black but as the filter gets clogged with the fine carbon it then starts to run clear (we pour the first still black filter back in to the bucket). We try to get a drip rate that gives us a liter of fluid every 24 hours but have over stirred some times and has taken longer, the way we look at it is the longer the better the filter.
Flavoring
This is of course personal choice.
You can buy a huge range of ready made flavors for all types of alcohol including liquer They all have different tastes so you do have to try and test, but if you live in Auckland NZ their is a superb brew shop called hauraki home brew near Albany and the lady is the shop is superb mine of information on all aspects of brewing and the flavors you can get what they will taste like compared to shop bough spirits.
We have now found the Bourbon, rum (white and dark) and Brandy flavors that we like but we have also flavored our own vodka using peel from different fruits that we grow in the garden. We have also made a Pomegranate vodka and liqueur. We are going to try some more stuff this year and i will add as we try.