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Distillation
A still (short for distillation unit) is a device that separates a mixture of 2 or more different liquids into their individual components. For example, it will take a mixture of oil & water & separate the oil out of the water. Other common uses are the separation of petrol from crude oil & the separation of alcohol from a fermented liquor that contains alcohol & water. We will use the alcohol/water mixture to explain this process below. Distillation works when the mixed liquids will boil at different boiling temperatures. Water boils at 100°C; ethanol (the alcohol we drink) boils at
about 80°C.
If a mixture of water & ethanol is heated, it will start to boil at around 80°C. In fact, it is mainly the ethanol that is boiling, not the water. This means the steam that is rising is mainly ethanol. When this happens in a still, the ethanol steam is cooled so it turns back into liquid form & it is
collected outside the still. While this is happening, most of the water stays behind in the still which means that the ethanol has been separated from the water.
Basic components & how they work
Stills have two basic components. A boiler to make the steam and a condenser to cool the steam & collect the alcohol. Condensers are cooled by cold tap water running through tubes & cooling jackets around the condenser steam chambers.
The boiler constantly boils the liquid mixture (which is called the "wash")
to provide steam or vapour for the condenser. The vapour that is boiled off actually contains a mix of alcohol, water & some by-products from the fermentation. This is due to the fact that some water evaporates while the alcohol is boiling. The amount of water in the vapour changes as the
distillation proceeds. In the early stages of boiling a wash, the vapour is mainly alcohol with a little water. During the later stages of the distillation, the water content increases. This means the alcohol collected early will be stronger than the alcohol collected towards the end of
distillation.
The condenser then cools the vapour thus turning it back into purified liquid which drips out a drain tube to be collected. The boiler & the condenser need to be balanced so the rate of boiling matches the cooling capacity of the condenser. The temperature of the wash also changes during distillation. When there is plenty of alcohol in the wash, it will start boiling just below 80°C. As the
process proceeds & the alcohol is removed, the boiling temperature starts to go up. This increase in temperature will continue till the last bit of alcohol comes off at about 93°C. At this point, there is no alcohol left in the boiler but it does contain most of the original water. The process is
now finished & the still is turned off.
Types of Still
There are two basic types of condenser. Pot and Reflux.
A pot condenser collects all the vapour and converts it to liquid.
A reflux condenser is actually made up of two condensers, the first one, the reflux condenser, removes impurities & water from the vapour before the vapour passes through to the second condenser where it is cooled & collected.
Still spirits range of stills
Still Spirits is New Zealand's leading supplier to the home crafted spirit & liqueur market. They offer the following three variations which will give different results depending on your requirements.
1. Pot Still
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Still Spirits POT still |
| This unit has a simple pot still fitted where all the vapour that is generated by the boiler is collected and condensed back to liquid. It produces a low strength spirit which will contain some impurities that may influence the taste of the spirit. It needs to be stressed that these impurities are not dangerous if the wash has been produced using Still Spirits ingredients as described in the Distilling instructions. The spirit collected is suitable for all types liqueurs and spirits where mixes are used |
2. Turbo Air Still
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Still Spirits Turbo Air Still |
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An air still is a special type of pot still that uses air instead of water to cool the condenser. An inbuilt fan blows cool air over the cooling coils inside the top cover. This obviously provides a great saving of precious water.
Because it is a “pot” type still, the alcohol produced will contain some impurities if they are present in the wash. This means that it is essential that the wash should be very clean to start with. The only way to achieve this is to use the very best quality yeast to ferment any wash for an Air Still.
The new Still Sprits' "Triple Distilled” Turbo Yeast has the extraordinary ability of producing alcoholic wash that is so pure, it compares with commercial "triple distilled" spirit once you run it through a still. It is now available with the Still Spirits Turbo Air Still. No other Turbo yeast product possesses the clean spirit technology of Still Spirits Triple Distilled.
Like the yeast, the Still Spirits Turbo Air Still is also the best on the market. It is a compact bench top unit that distils 4 litres of wash to give you 1 litre of drinking strength spirit each time you use it. The whole process takes about 2 hours & is completely straightforward with no complications.
A very important factor is that other air stills on the market are designed to distil water. When these are used to distil alcohol, they work too hot & fast to produce good quality spirit because more impurities are generated in these conditions.
The Still Spirits Turbo Air Still is designed to work at the correct temperature & rate for alcohol distillation & therefore produces better quality spirit.
BEWARE OF CHEAP IMITATIONS The Still Spirits Turbo Air Still is high quality stainless steel (not brushed or anodised metal) & has a heater specially designed for spirit distillation. Other stills are principally designed to distil water only.
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Still Spirits REFLUX Still |
3. Reflux Still
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This unit has a reflux condenser fitted before the main condenser. Before the steam moves across to the main condenser, it passes up through the vertical reflux condenser column which has a small cooling water jacket around it. This causes some of the heavier vapours including water & impurities to condense and drip back into the boiler.
The vapour that makes it through to the main condenser is mainly alcohol vapour that has had most of the impurities & a lot of the water removed. As a result the spirit collected by this type of condenser is higher in alcohol strength than a pot still and contains less by-products. The spirit collected is suitable for all types of spirits and liqueurs.
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4. Super Reflx Still
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Still Spirits SUPER REFLUX still |
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This unit has a complex reflux condenser. This condenser contains ceramic saddles which provide the ideal surface for condensation. These are housed in a jacketed condenser with cooling water circulating around the condenser.
This creates a controlled temperature environment where the vapour comes into contact with the ceramic saddles and bounces from one to the other as it makes it's way through the condenser. As a result the vapour comes into contact with a huge surface area so that it is repeatedly treated before passing through to be condensed and collected by the main condenser. As a result the spirit collected by this type of condenser is even higher in alcohol strength than either the pot still or our standard Reflux still and contains even less by-products.
The spirit collected is ideal for all types of spirits and liqueurs and produces a spirit even more suitable for producing gin, vodka and other delicate spirits that are drink neat or with little to mask the flavour of the spirit.
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