Potash to Pearlash

It wasn’t long after potassium carbonate was finally isolated as the key ingredient in potash (Antonio Campanella, 1745) that enterprising chemists got interested in refining it, taking the extra step of heating potash to burn away its ashy residues. This had the effect of turning the powder a sparkling white, which thence became know as “pearl” ash (now THAT’s good marketing).

The main use for this material was again for glass-making. Yet being such a strong alkaline it was also great for making soap (alkaline + fat = saponification which…oh heck, more on that another time). Yet the act of refining potash had the added benefit of removing the burnt wood flavor from the product, which cleared the way for its large-scale use as a leavener.

The first published recipe to call for pearlash — a type of gingerbread — was published in 1796 by one Amelia Simmons. It was the beginning of a chemical leavening revolution that would spread around the world.

4 thoughts on “Potash to Pearlash”

  1. “(alkaline + fat = saponification which…oh heck, more on that another time)”

    Joe was that a hint that you will be making soap or candle themed pastry at some point in the near future?
    The only one I can think of that we see today is the birthday cake, whose history you have yet to touch upon.

    1. Actually I never thought of that. It might be fun to make some soap! That would be a great addition to the “totally not pastry” section because, well, it’s totally not. Birthday cake history is an interesting idea. I tried to research that once, but got frustrated trying to figure it out. It’s high time I made another attempt. Thanks Trenton!

  2. Well you already rendered lard in your pizza oven, and that very same oven produces ash, which produces lye (assuming you enjoy creating extremely caustic and dangerous chemicals in your backyard). You definitely have a scale. The only thing you are missing is some essential oils that Mrs. Pastry enjoys!

    Love the site, its purpose is pure and its execution is all the more elegant for its simplicity, keep up the good work.

    1. You’re so right, Trenton, I do have all the components on-hand and available. Consider soap officially added to the Joe Pastry project list. Thanks also for the very kind words. – Joe

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