My grandfather was what they call in the United States a “revenooer.” He was the excise man for the Scotch whisky distilleries in Campbeltown, a little town on the west coast of Scotland. I was born there and still vacation there. A little town now, but in its heyday it had more than 30 distilleries. There was a distillery/maltings not far away from our house, and as a little boy I routinely played in the maltings with the cats who “lived” in the barley. I retained an interest in Scotch whisky, including drinking it when I was old enough, and was thrilled when Rabbi Safran asked me to audit some distilleries which wanted OU kosher certification on their single malt whiskies. One of them was only a few miles over the water from my vacation cottage!
Scotch whisky production is not complex. Malted barley, yeast and water get fermented. The weak alcohol from the fermenters is distilled in old copper batch stills – not an efficient way to make pure alcohol but the only way to make the liquid gold that is a malt whisky — aged in barrels/casks and then popped into bottles with a little caramel color. Bottling is not usually done at a distillery but at dedicated bottlers.
The kosher problems are not at first obvious. Yeast is rarely a problem in the whisky industry; caramels likewise. Some distillers, though, may add a little antifoam to make distillation more efficient, and this can be a problem. Antifoams are little understood (magic, in fact) and can be made from almost anything, with the result that some are not kosher. This issue, however, is easily dealt with because antifoams are not part of the mystique of Scotch and are changeable. Casks, on the other hand, are very much part of the mystique.
Scotch is almost invariably aged in used casks, usually from United States Bourbon production. The chemistry of the interaction between cask and whisky is complex. The effect on flavor is also not simple. The use of casks which had previously held sherry or other grape-based wines is believed by some to improve the product. Thus a growing range of single malts are now aged for at least some period of time in such casks. This raises an instant kosher issue, and for kosher-certified whisky such casks must not be used unless they are from a kosher sherry production and are kosher certified (not yet available in large numbers). Happily, there are a number of distilleries where Bourbon casks are still the norm. Also happily such casks are easy to identify.
There is a demand for kosher sherried whiskies. For the future – and kosher Scotch has a big future – we are considering possible techniques to turn existing not-kosher sherry casks into kosher ones. This would significantly reduce costs of such kosher runs. One obvious technique would be to char the interior of the cask. Alas this would destroy the virtues of the sherry cask for whisky aging. If the cask surface was very smooth, non-porous and uncracked, another approach would be to rinse the cask with boiling water. Whether the cask interiors would be smooth enough is one issue. Whether this would again destroy the virtues of the sherry cask is unknown. A less drastic approach currently under discussion is to use a technique more usually applied to make wine tanks kosher. In this the cask would be washed and then filled with cold water and left for 24 hours, with this process repeated three times.
Bottling plants are the major issue. A single bottling plant can handle a wide range of whiskies from heavily sherried to never sherried — which are of course by now out of their recognizable barrels and into tanks. It is important to ensure that the systems and tanks involved can guarantee separation and that the tanks never hold a wined whisky long enough for it to become not kosher. Distilleries are easy to audit but bottling plants take much more effort. Distilleries tend to be old fashioned, located in utterly beautiful, remote parts of Scotland and are a pleasure in every way to visit. Bottlers tend to be much more industrial, near the large cities, and are less exciting. Despite this, one characteristic feature of the whole industry is the friendliness and helpfulness of everyone one encounters. They are excited about their product and it shows.
Dr. John Meyer was born in Scotland and educated in Scotland, England and New England. He has a B.Sc (1st Class honours) from the UK and an Sc.D from MIT — both in Chemical Engineering. He has written a number of scientific papers and patents and worked for twenty years in the chemical industry, both in R & D and Plant Management, and lectured in Chemical Engineering in the UK. Since then he has worked mostly in the field of kashrut, spending the last 15 years with the OU. His specialty is microbiological engineering.