The icon indicates free access to the linked research on JSTOR.

The world runs on fossil fuels. In other words, we burn the remains of plant life that populated the Earth hundreds of millions of years ago. At the beginning of the Industrial Revolution in Europe, there was another important kind of plant-combustion, for large-scale industrialization was dependent upon ashes, or potash.

JSTOR Daily Membership AdJSTOR Daily Membership Ad

Potash (from the Dutch potaschen) is made from the burning of wood, weeds, agricultural waste, ferns, and algae. The potassium salts in the resulting ashes were needed for numerous industrial processes. Ceramics and textiles were industries at the heart of the Industrial Revolution, which was first jump-started in the British Isles. The alkalis (from the Arabic for ashes) from burnt organics were used to make soap, glass, ceramics, saltpeter for gunpowder, and even leavening agents for baking. They were also used to bleach linen and clean and dye wool.

Typically, the ashes were distinguished by quality—“wood,” “woad,” “white,” “blue,” and “pearl” ashes were known categories, for instance, with “soap” ashes the most common.

“‘Potash’ was a more refined product,” writes historian Paul Warde, “which only appeared on the English market during the 1590s but rapidly came to dominate it.”

Industrialization in Britain became dependent upon the forests of distant places—first northern and eastern Europe and then North America. Among other historical sources, Warde cites Carl Linnaeus’s 1749 description of potash-making in Sweden. Old beech trunks were burnt, the resulting ashes kneaded into a paste with water and then smeared on fir or pine sticks and burned again in stacks. This second round of ash was removed when red hot, then “dissolved in water to make lye that was heated in a pot, leaving a dark alkaline residue.” This could be further heated in an oven to make the highest quality “pearl ash” preferred by dyers.

Warde has reconstructed the details of this vital British ash trade. Wood ashes were already being imported into London in the 1480s for the manufacturing of soap used for washing wool rather than people. The ports of Danzig, Königsberg, and Riga on the Baltic Sea were the primary exporters. By the middle of the 1500s, the British had banned the export of home-made “white ashes.” Industrial demands were unsustainable: British forests could not provide enough hardwood to be burned for the highest quality ashes. Starting in the mid-1600s, the British demand for potash reached further north into the White Sea region. Swedes, Poles, Russians, Lithuanians, Livonians, Finns, and others harvested the wood and burned it to ashes for the trade.

So, from the start, the Industrial Revolution had an ecological impact far from the sites of manufacturing.

“To obtain a large amount of ash one needs to burn a very large amount of wood,” writes Warde. One historical account states that 700 kilograms of beech were needed to make a kilogram of potash; a kilogram of potash could also be made from 2,000 kilograms of spruce. The “demand for wood that was turned into ash and imported into Britain and the Netherlands completely dwarfed the demand for much better-known trade in timber and naval stores.”

The vast forests of North America were next. After many fits and starts, potash-making in the North American colonies finally starting to boom during the 1760s. By 1792, Britain was importing 14.2 million pounds of potash a year. In 1810, a peak year before the resurgence of the Napoleonic Wars, 36 million pounds of potash came into Britain, most of it from Canada. Warde notes that this 36 million figure is equivalent to the “entire annual wood production” of the German states in 1810.

Industry had become environment-devouring.

Meanwhile, the very first US patent, granted in 1790 to Samuel Hopkins, was for improved techniques of making potash to be used for fertilizer. Potash is still used for fertilizer. Only instead of boiling wood ashes in pots, potash is now derived from mined potassium ores. Potassium was first isolated in 1807 by the British chemist and inventor Humphrey Davy. He named the stuff after potash.

Support JSTOR Daily! Join our membership program on Patreon today.


JSTOR is a digital library for scholars, researchers, and students. JSTOR Daily readers can access the original research behind our articles for free on JSTOR.

Past & Present, No. 240 (AUGUST 2018), pp. 47–82
Oxford University Press on behalf of The Past and Present Society