Out of the Ashes

A Brief Local History of Potash and Pearlash

Illustration by Herbert M. Stoops.

Written By

Pat McGovern

Written on

June 01 , 2012

Salt, spices, and baking soda: these culinary staples posed a major challenge to Upper Valley localvores attempting our first 100-Mile Diet Challenge in August 2005. Such products couldn’t be found locally. The closest salt works were in Maine, just beyond our 100-mile radius. We had access to local herbs but few spices. And we wondered: just what is baking soda?

Thoughts went back to colonial times. What had our Upper Valley ancestors used for leavening? Sourdough starter was a possibility for bread, and popovers and sponge cake could be made with egg whites. But what about cornbread, gingerbread, biscuits, and cookies? That question was a tug on a thread whereby things started to unravel; tug on the history of baking soda and lots of fascinating history comes with it.


Early colonial settlers faced a forested landscape when they first reached Vermont. They worked hard clearing the woods to create open land for homes, crops, and pastures. According to A History of Norwich Vermont, published in 1905, “There was a welcome source of extra income in sending the straightest, largest logs by water to Hartford. But the greatest profit came through burning them. By a process of leaching and boiling, large hardwood logs were manufactured into potash and pearlash.” The ashes were mixed with hot water and the resultant caustic lye (which could be used as bleach) was drained off. The lye was boiled down, resulting in a black residue known as black salts. The black salts were heated until they fused into a molten mass: potash.


Potash, a crude potassium carbonate, was used in the manufacture of soap, glass, and gunpowder, and for cleaning wool. When Great Britain needed potash for their Industrial Revolution, the new colonies were a great resource. Asheries sprang up in many towns, including Norwich, Hartford, Woodstock, Newberry, and Royalton.

It took 200 bushels of ashes to make 100 pounds of potash. Some individuals made potash their main business while others were able to get cash or barter for goods by selling ashes, including their fireplace ashes. (A Vermont Journal ad states: ”The subscriber will pay 14 shillings per hundred weight in cash for well-dried SALTS OF LYE or #18 shillings per hundred, ¼ part money and the remainders in goods for any quantity delivered to his store in Windsor. He hath on hand a quantity of shoe leather of good quality.”)

Pearlash was a further refinement of potash. It was used in the manufacture of pottery, china, and soap, and as a chemical leavening agent in baking. It is a bit of a mystery as to how a caustic lye product, used for bleaching textiles, ended up becoming a staple of early American bakers. (There were reported deaths from accidently drinking dissolved pearlash.) It is known that Native Americans used ashes in their cooking. The Abenaki boiled corn in lye made from wood ashes when making soups or hominy (a boiled corn they called kakiwatal). Navajos used the ash of junipers and Hopis used the ash of chamisa bushes. Ash has a high mineral content and adds nutritional value to food.

In his book Baking Soda Bonanza, Connecticut chemist Peter Ciullo writes that by the 1760s, settlers were adding pearlash to sourdough; when a small amount was mixed with a mild acidic solution like sour milk, vinegar, honey, maple syrup, or molasses, carbon dioxide bubbles formed, causing quick breads and cakes to rise.

Feeding America: The Historic American CookBook Project at Michigan State University indicates that the first known cookbook to use pearlash as a leavening for dough was American Cookery by Amelia Simmons in 1796. (Simmons’s book was also the first to bring together certain Native American products, such as corn, turkey, cranberries, and squash, and apply them to English culinary traditions.)


The American Revolution had made Britain and other governments and industries wary of dependence on American potash and pearlash, but Europe had limited woodland to sacrifice to wood ash. As a result, the French Academy of Science offered a prize for the best process for converting sodium chloride to soda ash (sodium carbonate). Nicholas LeBlanc won the prize in 1791. He went on to build a “soda ash” business, but it was confiscated by the French revolutionary government, which refused to pay him the prize money he had been entitled to 10 years earlier. In 1802, Napoleon returned the plant (but not the prize) to him, but by then LeBlanc could not afford to run it. He killed himself in 1806.

The sodium carbonate production process continued to be improved and, in time, Europe no longer had to depend on American pearlash. In 1846, New Englanders John Dwight and his brother-in-law, Dr. Austin Church, began the manufacture of bicarbonate of soda, called Dwight’s Saleratus, which became the Arm & Hammer baking soda we know today.

By 1790, potash and pearlash were Vermont’s leading exports, and the state, which had been 95 percent forested in the 1760s, was largely deforested. George Perkins Marsh, now known as the “Father of the American Conservation Movement,” had grown up in his family home on the slope of Mt. Tom in Woodstock and noticed the erosion and loss of topsoil caused by the clearing of land, as well as the destruction of fish habitats by siltation.

As Vermont’s representative to the U.S. House of Representatives, Marsh warned farmers of the dangers of continued clearing of the land and described responsible forest management practices being used in Europe. In an 1847 speech he stated that “steep hillsides and rocky ledges are well suited to the permanent growth of wood, but when in a rage for improvement they are improvidently stripped of this protection, the action of sun and wind and rain soon deprives them of their vegetable mould….They remain thereafter barren…producing neither grain nor grass.” As stated in A History of Norwich Vermont, “As early as 1830, the tide began to turn. The land was showing signs of weakness, the pioneers had mined it rather than cultivated it.”

While Vermont continued to be a major producer of potash and pearlash into the 1840s, many Vermonters turned to sheep and wool as their cash crop.

Today, much of our baking soda is processed from the natural mineral deposits of trona in the Green River Basin of Wyoming, the world’s largest known deposit of trona ore. (Green River trona was created by the evaporation of a highly alkaline ancient lake.) It is the basic ingredient in baking powder (which has added acidifiers, such as cream of tartar and/or aluminum sulphate and drying agents such as cornstarch). We no longer use pearlash in baking, but traces of the importance of potash/pearlash in Vermont’s history remain in names such as Potash Bay in Addison and the Potash brooks and Potash Brook roads in many Vermont towns.

A version of this article originally appeared in Upper Valley Image.

Illustration by Herbert M. Stoops. “Today’s Thrift Provides for Tomorrow”, May 21, 1945. Used by permission of National Life Group. Montpelier, VT.

Recipe for Cookies
(from American Cookery, by Amelia Simmons, “an American Orphan,” 1796)

“One pound sugar boiled slowly in half pint water, scum well and cool; add two teaspoons pearl ash dissolved in milk, then two and a half pounds flour, rub in 4 ounces butter and two large spoons finely powdered coriander seed, wet with above, make rolls half an inch thick and cut to the shape you please; bake fifteen or twenty minutes in a slack oven, good three weeks.”

Gingerbread Recipe
(from The American Frugal Housewife, Dedicated to Those Who Are Not Ashamed of Economy, by Mrs. Child, 1833)

“A very good way to make molasses gingerbread is to rub four and a half pounds of flour with half a pound of lard and half a pound of butter, a pint of molasses, a gill of milk, tea-cup of ginger, a tea-spoonful of dissolved pearlash stirred together. All mixed, baked in shallow pans twenty or thirty minutes.”

About the Author

Pat McGovern

Pat McGovern

Pat McGovern is a retired teacher, an advocate for local foods, and one of the founders of Upper Valley Localvores. (Check out her blog at uvlocalvores.wordpress.com) She is also a volunteer manager of the Canillas Community Garden in Lebanon, NH.

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