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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 AND 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.
BASIC COMPONENTS AND HOW THEY WORK
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
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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
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Still Spirits REFLUX Still
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2. Reflux Still
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This unit has a simple reflux condenser. Before the spirit is condensed by the main condenser, it passes through a small reflux condenser that is jacketed with cooling water. The vapour is forced to come in contact with the surfaces of this condenser and some of the heavier vapours including water vapour are condensed and returned to the boiler.
Only the lighter vapours, with a higher boiling point, make it through the reflux condenser to be condensed and collected by the main condenser. 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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3. Super Reflux 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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There are two basic types of condenser. Pot and Reflux.
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