General principles

Before starting any job, it pays to think about what you want to do, and whether you can do it with the tools and materials you have. It would be nice to be able to duplicate any commercially produced beverage at will, but is it realistic? Unfortunately, the answer is no, because many factors are involved in creating the specific flavors in a product. However, you can duplicate many, and come close to many more. In this chapter we discuss how to operate the three types of still to produce different types of beverages.

A fermented product is a very complex mixture, containing dozens, if not hundreds of different compounds, and the distiller's task is to extract only a few. The fact that different compounds have different boiling points makes this possible, but it is very difficult to produce a specific mixture of a few components from such a complex starting point.

The boiling point of a mixture changes with the proportions of the mixture. This fact of nature determines the results obtained with each type of still. A simple pot still produces vapor that is rich in all the more volatile components, but does little to separate them from one another. The slight separation you do get can be increased by careful still design. An important element of a pot still is how vapor is transported from the boiler to the condenser. A traditional whiskey still has a gently curving dome with a long, narrowing, Swan's neck (also called a Lyne arm) to the condenser. Vapor condenses on the inner surfaces of the dome and the upright part of the swan's neck, creating some reflux and increasing the proportion of volatiles in the product. A simple pot still with a long, uninsulated upright tube to carry the vapor from the boiler to the condenser will give a slightly stronger product than one with a short tube. Adding a fractionating column will enhance the separation enormously by increasing the amount of exchange between vapor and condensed liquid. Adding a special condenser to increase and control the amount of reflux provides the best possible separation, allowing each component to be collected separately.

From our point of view, as small-scale distillers, the major difference between the different types of still is their relative ability to separate substances from one another. The fractionating column is much better than a pot still at doing this, and the compound column is as good as it gets.

The first substances to come out of any still are the most volatile compounds. Many of these are toxic substances, and they should be discarded or saved for another use, like fondue fuel. This first "family" of compounds is usually quite small, giving way quickly to a larger group of volatiles that arrive with the first part of the ethanol. This family, called the heads, contains some compounds that add flavor to spirits like whiskey, brandy or rum, but are undesirable in a pure ethanol product. The tails, which follow the main bulk of ethanol, contribute flavor, but also contain the toxins responsible for most hangovers.

If you want to try and make true flavored spirits like whiskey, brandy or rum, you need to keep both the heads and the tails and add a proportion of them back to the ethanol before aging. The small amounts of heads and tails will be altered by the slow chemical changes that occur during maturation in wooden casks. These compounds, along with flavors extracted from the wood, provide the flavor and body of the final product. Aging is the key process in the production of traditional spirits, and you may want to try it. Be warned, though - it takes years, skill and the correct environment to mature a fine spirit. Raw spirit tastes and smells nothing like the matured product, and the unaltered congeners in it are toxic headache producers.

Because making a good quality whiskey or brandy is so difficult, we will concentrate on the procedures required to isolate and collect the purest ethanol possible. If you want to flavor this, many rapid and simple options are available. There are many excellent essences on the market, and in the next chapter we'll show you how to make your own. After you have gained experience, you might want to try making a traditional product. Several good books on that advanced subject are listed in Appendix 8.

We will discuss the pot still, the fractionating still and the compound still in order, all using the same 30 liter (8 US gallon) boiler, containing a 20 liter (5.3 US gallon) batch. All the quantities and times mentioned in our examples are based on this 20 liter batch. 30 liters is a common size for a hobby still, but larger and smaller ones will work well. If you have a different size boiler, your quantities and times will change in proportion to the batch size. Boiler size has no effect on the dimensions of the rest of the still, which are determined by the laws of physics. A fractionating column needs to be 100 - 120 cm (3 - 4 feet) long, and its performance depends on heat input, not liquid capacity.

Doing two separate distillation runs can significantly improve the product. Commercial distilleries often do three! The first is a simple pot distillation to remove the solids color and much of the water that are in the fermented brew. The product collected in this run will be strong at first (around 60%), and will drop to zero as the run proceeds. The final average strength for the first run's product is usually 40%.

With very large batches (e.g. commercial whiskey stills) it's worthwhile removing some heads and tails at this first stage, but it's really not worth the trouble with batches smaller than 50 liters. If you have a boiler this big, you may find it useful to try.

If you are starting with a special ferment that containing 20% ethanol (see Chapter 1), then the first run can be omitted, but the benefits of higher concentrations are clear from the equilibrium charts in Chapter 2.

In the following examples, we will assume that several first runs have been saved up, allowing us to fill the boiler with 20 liters (5.3 US gallons) of impure 40% ethanol. This solution contains 8 liters of pure ethanol mixed with 12 liters of water and other compounds.

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