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Calvados and such
Hello guys, as a n00b survivalist who received some very useful input here I thought I'd repay the favour in the obvious way, by sharing info on a topic which I know well. The distilling subforum is an obvious gap in the forum's collective wisdom.
The ability to distil strikes me as a valuable one, given that alcohol is socially important in European countries and homebrew ciders and beers have a limited shelflife. A minimal amount of equipment and know-how would enable any community or farmstead to prepare short drinks for long-term storage, and has useful byproducts in cleaners and disinfectants.
I happen to be a fan of calvados, the French apple brandy derived from cider. It's also the case that surplus apples are usually available in the UK without too much effort, and that cidermaking is easy and sociable. But the following info deliberately omits any details of cidermaking in order to look at distillation in the abstract. You could feed any fermented drink through the following processes!
I'm happy to answer arising questions or to refer people to other sources.
The basic idea
Distillation is a physical process in which a complex liquid mix is boiled so as to separate it into its component fluids. It happens that we tend to be interested in ethanol and a bunch of other yeast byproducts knocking around in ciders or fermented barley brews, but note that distillation can have other outputs besides a nice tipple.
Legal and health issues
Distilling in the UK is a potentially illegal activity. Anyone operating a still should obtain a license from HM Customs and Excise and pay duties on their output. Distillation is also potentially hazardous, because an unskilled distiller can expose drinkers to methanol. The following info is thus presented 'interest only'.
The practicalities
Distillation can be achieved in all kinds of ways, of which there's plenty of technical discussion on the web.
A basic *pot still* is the choice of most home distillers who want to make a drinkable product and would be the logical starting point for any n00b. They can be bought off the shelf for a few hundred or cobbled together by anyone who can solder copper pipe.
Whether the still is bought or built, the basic operations of distilling alcohol are the same. The still is in effect a large kettle. The 'spout' of the kettle connects to a condenser, most often a long downpipe with a cold water jacket connected to the mains.
The still is part-filled with the fermented product and heated up slowly. As it boils, vapours rise from the surface of the liquid rise to the spout and condense in the downpipe, where they can be collected and bottled. Since different liquids boil at different temperatures, the still can be used to concentrate desirable parts of the mix and eliminate undesirable.
Most of the skill in distillation is in deciding how fast to heat up the fermented liquid and what to keep of the stuff that comes off it. Long-time distillers get a feel for this process, but beginners will probably want to put a thermometer at the top of the 'spout' to measure the temperatures at which the various condensing vapours were collected.
Many distillers will discard anything collected below a temperature of 80 or 85degC on the basis that it's likely to contain a high proportion of methanol. (Others will keep it for cleaning products.) As temperatures rise further into the eighties, drinkable ethanol starts to dominate the mix. Next come other alcohols and more complex molecules, and then as you move towards 100degC more and more water vapour.
Because the designs of stills vary, temperatures are guidelines rather than hard-and-fast rules. Practiced distillers know exactly what temperatures within this range will produce the outputs they want, and tweak their stills accordingly. But they also collect by the system of 'cuts', using a range of different collecting bottles for different temperatures within the acceptable range. They can blend these at their leisure to produce a drink with exactly the desired characteristics.
Back-of-an-envelope
Cidermakers will be aware that you use a lot of apples to make relatively little product. A standard 5.5 litre demijohn will need three or four bags of juiced apples to fill it. Similar considerations apply to beermaking.
Things get even worse when you start distilling. Say you wanted to distil some rather weedy calvados with a 50 per cent alcohol content. You'd need a minimum of 10 litres of 5 per cent cider to end up with one litre of calvados. (Actually, you'd need more, because some of the vapour is lost during distillation.)
Eight bags of apples => two demijohns of cider => one litre of calvados. Sheesh!
Build your own pot still
The considerations above make distillation a community-type activity.
I'd suggest that a 35 or 50 litre still is the smallest practical for calvados or whiskymaking. It will yield two or three 750ml bottles of spirit per firing. Such stills might be built out of beer kegs or milk churns and heated on calor gas burners or bonfires.
The 35 litre milk churn still which I examined a few years ago was designed for convenience, with all of its components tucking into the churn for storage out of season. When assembled, the churn was topped off with a lid of sheet copper with a short chimney of 2" copper pipe rising from it.
This 'chimney' was apparently stuffed with copper wool, and the lid ingeniously attached to the mouth of the churn using a cheap cylinder locking seal designed for assembling stainless steel air vents!
A 90deg angle at the top of the chimney led to a 15mm T-junction, one branch providing access for a thermometer and the other going to a downsloping run of 15mm pipe sections in a jacket of cooling water.
The design was simple but effective. The owner told me that, using this setup on top of a camping gas burner, it would take a couple of hours to distil one or two litres of calvados from 20--25 litres of cider.
Best, N.
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