stills, heat sources , have taken on many forms throughout history. Early distillers used wood and charcoal as heating sources, boiling the contents of the still over an open flame (gentler methods, such as nestling the still in a pile of warm dung, worked for some kinds of essence extraction but did not provide enough heat to distill alcohol). The Dutch in the seventeenth and eighteenth centuries were the world’s leaders in distillation, and also the first to use German Ruhr Valley coal, due to their lack of local fuelwood. The Dutch also made major advances in furnace and flue construction, sealing their stills into brick structures with better control of heat distribution and, equally importantly, lower costs in energy usage. England and Lowland Scotland began to exploit their coal pits to power the steam engine and usher in the Industrial Revolution—and to distill their grain spirits and molasses brandy. See rum. In the impoverished Scottish Highlands, with only 5 percent of its ancient forests standing by 1600, much of the populace was forced to use local peat to heat its homes, brew its beer, and distill its spirits. (Peat was also employed to dry the malted barley, where the smoky kilns gave Scotch whisky its distinctive “peat reek” flavor. See Malting.)
The exploitation of steam had major implications for the distilling industry: its use to heat stills, either directly or indirectly, significantly lowered costs, improved distillate quality, and, when injected directly into a continuous still, made a much lighter, purer spirit. By the early nineteenth century, inventors in the British Isles, western Europe, and the United States had patented numerous steam stills for batch distillation. In the United States, this would lead to the greatly simplified, surprisingly effective three-chamber still (later adopted in Germany for korn distillation as the “Blasenapparat”). See still, three-chamber. At the same time, others in Britain and France were perfecting the continuous or column still. See still, continuous. Both of these had steam injected directly into the still, where it would strip the alcohol from the wash. As the steam was generated remotely, any energy source could be used to produce the steam, without fear of it burning too hot or producing too much smoke: wood, coal, bagasse (the squeezed-out remains of sugar cane), oil, gas—all were acceptable.
By the 1870s, distillers had learned to heat pot stills with steam, which was either sent into the still through a sealed copper coil at the pot still’s base or sent into a jacket that covered the bottom half of the still. This prevented the burnt or “empyreumatic” taste caused by naked flame scorching the wash inside the still. Some distillers preferred to continue to use direct-fired stills, but by the second half of the twentieth century they had become increasingly rare, at least in the major industrial countries, with the major exception of France, which requires that cognac be distilled over an open flame; additionally, many Armagnac and calvados distillers still use wood-fired stills. (Of course, untold thousands of wood-fired pot stills also continue to operate in villages around the world.) At the same time, distilleries shifted from coal to on-demand oil and gas as more cost-effective fuels. In the twenty-first century, the industry has embraced renewable resources and biogas generation from waste products to produce the energy required to run a distillery and generate the steam to heat the stills.
See also France.
Neynaber, A. F. W. “On Distillation.” The Pharmacist, October 1876, 313–316.
By: Chris Middleton