Warning: It is illegal to manufacture strong spirits without a license in many countries. This article is not a document of actual events and is not intended to be a guide to spirits manufacture or any other unlawful activity. How the law stands on some of the topics discussed here is referenced later in the article.

Vodka is a colourless, odourless neutral spirit produced from anything with either a starch or sugar content. It is made by concentrating alcohol present within fermented material such as grain, potato, grapes and molasses, this is achieved via process of distillation. If you have every made beer, cider or wine at home you are half of the way towards making vodka.

The unique part about about vodka production is the purity required to make it taste more or less neutral. This level of purity can only be achieved by distilling the fermented liquid (or wash) to a very high percentage of alcohol, above 90% is the general consensus, but it needs to be at least 96% to be legally classed as a vodka in Europe. Because alcohol (or the ethanol part to be precise) is totally neutral, we are nearly eradicating any remnant of flavour or aroma from the product by distilling to 96%+. It’s called rectifying the spirit.

Of course you’ll never see vodka bottled at that strength, they are all watered down (with de-mineralised water) to around 40% abv after filtering.

The process of extracting the ethanol from the wash works on the principal that ethanol turns to gas at 78.3°C, whilst water only fully vapourises at 100°C. By heating a solution of the two to the correct temperature we can effectively boil off the alcohol, condense the vapour and collect a liquid that is stronger in alcoholic content than the one we started with.

Proportionally, ethanol doesn’t freeze until it reaches around -114°C. Around 1200 years ago eastern Europeans took advantage of this science and they were able to concentrate alcohol from wine by leaving it out in the freezing cold and scraping away slushy alcohol from off the top of the frozen water. An early form of vodka perhaps, but not the point of this post and certainly not something that I would recommend doing!

So how do you make vodka?

Fermentation

Well firstly you need to make alcohol. We can do this by selecting anything with a sugar or starch content. There’s plenty to choose from, but the most readily available and cheapest option is quite simply, sugar.

Table sugar can be converted into an alcoholic wash fairly easily and you get plenty of alcohol for your money, many budget vodkas are made from molasses (the bi-product of sugar refinery) as it is very cheap and contains lots of sugar. The only thing that table sugar lacks from a production perspective, is the yeast nutrients (potassium, salt et al) naturally present within things like grapes and grain. This is because table sugar is around 97% sucrose, so very little of anything else. Fortunately you can buy yeast nutrients for very little and supplement your fermentation with it.

“You require approx 17g of sugar for every %.litre of alcohol you want to make. Eg if you want to make 20L of a 14% alcohol wash, you need 17 x 20 x 14 = 4760g = 4.76 kg of sugar.” Homedistiller.org

Hold on a sec I hear you shout! How come all the best vodkas are made from grain, grape or potato? It’s a good point and it’s totally true that you’re much more likely to get truly great results by using grain etc. Don’t forget that making vodka requires a very high purity of distillate, so much of the character from the original product will be lost. The tiny nuances left over after distillation are what differentiates great vodkas and poor vodkas. One thing that a sugar based vodka will certainly lack is the mouthfeel, texture and viscosity of a wheat or potato vodka.

The final factor to think about in fermentation is the yeast. All yeasts work differently to one another, with some working very quickly and others taking quite a while. Some yeasts are not capable of fermenting to higher strengths (above 12%), so distillers need to use the right one, champagne yeasts and turbo yeasts Turbo yeasts are specific strains designed to work very quickly. A turbo yeast usually comes in dried form and includes all they yeast nutrients required to make it work very quickly, it also includes dried citric acid, which is necessary to keep the relatively high PH that is important for fermentation are usually a safe bet.

It’s worth measuring the specific gravity (using a hydrometer) of your wort at this point, it will give you an indication of the potential alcohol yield and it’s also means of checking that fermentation doesn’t stall after a couple of days. This is also the only way to really know the resulting alcohol abv of your wash before distillation. Fermentation is finished when the specific gravity reads 0.990-0.980, this should take about a week (only around 48 gours with a turbo yeast), the other indication being no more bubbles rising to the surface. The main factor to be aware of is the temperature of your wash Different yeasts prefer different temperatures, but between 20-26°C is a safe bet, even higher for a turbo yeast as this significantly affects the rate of fermentation.

Distillation

I think it is worth reiterating that the distillation of strong alcohol within many countries is illegal.

Here is how the law stands in the UK (taken from Alcoholic Liquor Duties Act 1979).

The penalty incurred in the event of any of the above is detailed below (Finance Act 1994).

Once again, this blog does not condone, encourage or participate in any illegal activities (relating to that of making spirits anyway!).

Distilling to 90%+ requires specialist equipment and precision temperatures. In order to rectify a spirit the distiller needs to have a still capable of generating reflux in a column. Reflux is the procedure of holding a stable temperature within the column of a still, by controlling the temperature at both the top and bottom of the of the neck.

The bottom of the column (near the heat source) will always be hotter than the top. The hot bottom encourages the water and alcohol present within the wash to evaporate up through the column. At the top of the column cooling water is used to regulate a temperature of 78.3°C, the boiling point of ethanol. As the various spirit and water vapours travel up through the column they pass through packing material, this can be in the form of copper, ceramic, steel or any other material that conducts heat well. This material helps to hold a steady decrease in temperature from top to bottom. As a result of this, any compound with a boiling point higher than 78.3°C will at some point during its journey to the top of the column, condense back into a liquid and fall back to the bottom of the still. Any compound with a boiling point lower than, or including, 78.3°C (i.e ethanol) will find it’s way to the top of the column and the condenser.

Below is a picture that I found of a still operating with a perfect temperature at the top of the column.

Once the pure spirit vapour reaches the condenser it is cooled and converted into liquid form and it then drips out as nearly pure ethanol.

Cutting

Ethanol is not the only type of alcohol present within an alcoholic wash, you will also find trace amounts of methanol (boils at 64°C) and acetone (boils at 56°C) at the lower end of the scale and propanol (82°C) and butanol (116°C) at the higher end. A good distiller will make every effort to remove these other alcohols from the distillate by cutting out the start (foreshots) and end (feints) of the run, leaving only the ethanol that flows in the middle of the process. Why? Well the lighter alcohols are very dangerous, they can kill you, and the heavier alcohols like propanol tend to smell and taste pretty nasty, as well as containing lots of congeners. The first part of the run also contains the volatile aldehydes, which are produced during fermentation via the oxidisation of ethanol, though not necessarily dangerous, they do give a rather pungent aroma that is undesirable in vodka.

Those very light alcohols that boil at a lower temperature than ethanol are extremely keen to escape at the start of the run, with that in mind the first liquid to flow through (the first 5-10% for example) is discarded until the distiller that the run is of a high purity.

As the ethanol extraction comes to an end heavier alcohols will begin to dominate the top of the still along with water. The distiller will notice a drop in alcohol purity of the distillate and a sudden temperature increase of around 4°C. It is at this point that the distiller must redirect the flow of distillate and stop collecting the heart of the spirit. These ‘feints’ or tails contain a group of compounds collectively known as fusel oils. Fusel oils will contribute a significant aroma to the product if not cut away and it is the retention of these compounds that mark much of the difference between western (pure) and eastern (characterful) styles of vodka. The final product should register at least 90% abv using an alcometer, this figure should be adjusted according to the temperature of the alcohol.

The next step involves cutting the heart of the product to a maximum of 73% abv ready for filtration. It is important that the abv is low enough so as not to break down the structure of the activated charcoal during filtration. Check out my article on filtration for an in depth look at the purpose and gains from the process. Filtering can be done through either a dedicated column filter packed with charcoal or even a Brita water filter from the kitchen!

Finishing

After filtration the final stage is to cut the spirit to bottling strength. There is evidence to suggest that a resting period in stainless steel can benefit the product at this stage, but it is not essential (neither is filtering for that matter). Most vodkas are bottled at 38-40% abv, so diluting the alcohol to this strength (with de-mineralised water) is all that is left to do.

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