Pearlash is powdery and slightly moist.
The History
If you were to scoop the ashes out of your fireplace and soak them in water, the resulting liquid would be full of lye. Lye can be used to make three things: soap, gun powder, or chemical leavener.
A “leavener” is a substance that gives baked goods their lightness. Today, we think nothing of adding a teaspoon of baking soda or baking powder to our cakes and cookies. But using chemicals to produce the carbon dioxide necessary to raise a cupcake is a relatively new idea.
Before chemicals, cooks would use yeast. Not just in bread, but yeast was often added into cake batter, along with a helpful dose of beer dregs or wine. The alternative was whipping eggs to add lightness, like in a sponge cake, although that particular recipe didn’t become popular until the end of the 19th century, after mechanized egg beaters were introduce.
Sometime in the 1780s an adventurous woman added potassium carbonate, or pearlash, to her dough. I’m ignorant as to how pearlash was produced historically, but the idea of using a lye-based chemical in cooking is an old one: everything from pretzels, to ramen, to hominy is processed with lye. Pearlash, combined with an acid like sour milk or citrus, produces a chemical reaction with a carbon dioxide by-product. Used in bakery batter, the result is little pockets of CO2 that makes baked goods textually light. Pearlash was only in use for a short time period, about 1780-1840. After that, Saleratus, which is chemically similar to baking soda, was introduced and more frequently used.
I was curious to try this product out and see if it actually worked. I ordered a couple of ounces from Deborah Peterson’s Pantry, the best place for all your 18th century cooking needs. I used it during my recent hearth cooking classes in a period appropriate recipe.
The Recipe
The recipe, for orange-caraway New Year’s Cakes, came from the cookbook-manuscript of Maria Lott Lefferts, a member of one of the founding families of Brooklyn. The use of pearlash, plus a recipe for “Ohio Cake,” serves to date this book to about 1820. It looks like this:
“New Year Cake
28 lbs of flour 10 lbs of Sugar 5 lbs of Butter
caraway seed and Orange peal”
This recipe doesn’t mention pearlash, but several of the other recipes in this book do. I checked the first cookbook printed in American, Amelia Simmon’s American Cookery, for an idea of how much pearlash to add. Here is the recipe I came up with:
New Years Cakes
Based on Marie Lott Leffert’s cookbook, c. 1820
1 cup light brown sugar, packed
1 stick salted butter
3 teaspoons pearlash dissolved in 1/2 cup milk
4 cups all purpose flour
Zest and juice of one orange
1 tsp ground caraway and 1 tsp whole caraway
Whisk together flour, zest and caraway. Beat butter and sugar until light and fluffy. Add orange juice and pearlash, then mix. Slowly add flour; mixing until flour is incorporated. Put in freezer one hour. Break off small pieces and roll very thin; cut with a cookie cutter or knife. Preheat oven to 300 degrees. Bake until cookies are slightly golden on the bottom, about 10 minutes.
***
Cookies leavened with pearlash come out of the oven.
The Results
I made the dough in advance and froze it, then dragged it to Brooklyn to be baked in a very period appropriately in a wood fire bake oven.
When the cookies came out of the oven, they had risen! They gained as much height, and as much textural lightness, as a modern cookie made with baking powder.
But how did they taste? The first bite contained the loveliness of orange and caraway (for a modern version of this recipe, I highly recommend using this recipe, and replacing the coriander orange zest and caraway). But after swallowing, a horrible, alkaline bitterness filled my mouth. My body reacted accordingly: assuming that I had just been poisoned, I salivated uncontrollably.
At first, I wondered if I hadn’t used too much pearlash. But then something dawned on me: the earliest recipes to use pearlash were gingerbread recipes. Of the four recipes in Simmon’s cookbook, half of them were for gingerbread. A highly spiced gingerbread probably did a lot to hide the taste of the bitter base chemical.
And that’s why I like historic gastronomy. If hadn’t actually baked with pearlash, and tasted it, I never would have made the gingerbread connection. There’s something to be said for living history.
I’ve been wanting to try baking with Pearl Ash for ages now . . . Thanks for the post!
It was an interesting experiment, but there is no advantage I saw over modern leavening. Give it a try and let me know how it goes!
I would love to know what the Ohio Cake consists of! Do tell!
I am out of town, but when I return to new york, I’ll look it up. It seemed like a pretty basic butter cake. I wonder whre the recipe came from–I imagine it being the official cake of Ohio’s statehood celebration.
You’re my hero! I once had a long conversation about pearlash with a chemist (actually, she was a metals conservator, for which chemistry is a strong prerequisite). I don’t recall how it came up, but I’m pretty sure we realized that pearlash had to be used along with an acid, like vinegar or lemon juice. I wasn’t clear whether that was meant to activate it, or perhaps to balance the taste? I seem to remember that it mattered when you added the pearlash and the acid as well, i.e. they went in together. Did you use the orange juice called for in the first receipt? If not, I wonder if that would help make future batches a little more edible. Or perhaps you aren’t eager to repeat the experiment ;-).
I think 1 teaspoon of pearl ash would have been quite enough. I know that if too much baking powder or soda are added the taste can be rather acidy. Yes, good old gingerbread cookies are great for masking taste, but make the soft kind, not the hard ones. Or make gingerbread cake.
When growing up we had dairy cows and gave them Black Strap Molasses which came in five gallon buckets. We would dip some out first to use in baking. This molasses has a very strong flavor and can pretty much match anything else.
Too much pearl ash and not enough acid ingredient. If you had used the same amount of modern baking soda the result would have been the same – terrible. Just because you are using historic recipes doesn’t allow you to leave common sense behind. The rules of chemistry and taste have not changed. The rule of thumb for baking SODA (not powder) is about 1/4 tsp. per cup so 1 tsp. would have probably been enough. And you should have used sour milk (buttermilk) for more acid.
It’s not clear to me why you would want cookies to rise in the first place, so the original recipe had no pearl ash. I’m sure Maria is giving you dirty looks from the grave, wondering why you messed up her delicious recipe.
In any case. potassium compounds are known to have a bitter aftertaste. This is why pearl ash was replaced with the sodium based saleratus (baking soda). But using 4 x as much as necessary and not balancing sufficiently with an acid would surely make the bitter taste even worse.
Gingerbread was popular long before chemical leaveners appeared.
pearl ash and baking soda are basic (ph > 7).
sour milk, vinegar, lemon juice are acid (ph < 7).
acid tastes sour.
basic tastes bitter.
"sour" and "bitter" are not quite the same.
So "…alkaline bitterness…" above is correct.
"not balancing sufficiently with an acid would surely make the bitter taste even worse." is correct.
but
"…too much baking powder or soda are added the taste can be rather acidy." is incorrect, has acid-sour, basic-bitter reversed.