Saturday, January 28, 2012

Pretzels: What goes in the bath?

8 oz Sodium Bicarbonate (baking soda)
I've been looking deeper into pretzels to develop my recipe, and learned a few things. I'm feeling a bit like a chemist now. Here's the deal: First, a Bavarian would say we're making pretzel-shaped brezels. Where I live, we say we're making soft pretzels, and can shape them various ways, including the traditional pretzel twist. Second, a Bavarian/German would say they must be dipped in a cold lye bath, then baked, to get that lovely deep pretzel color and taste.

A lye solution is a strong "base". In cooking, acids (lemon, for example) are common, but bases are not. Well, I'm not really ready to deal with lye in the kitchen just yet. The only other option I knew of was baking soda, which is a much weaker base, but is more kitchen-friendly. Then, I ran across this article, where they suggest baking your baking soda to get a stronger base.

They said that baking drives off water, making a stronger base, then you add it to a water bath. Hang on, then do you gain anything in the process? This is where it becomes chemistry. Baking soda is sodium bicarbonate, NaHCO3. When you bake it, you get sodium carbonate, Na2CO
2NaHCO3→ Na2CO3+ H2O + CO2
Hmm, then you mix the Na2CO3 with water, and you get more OH- than mixing the original baking soda would provide. I can't nail down the reaction, but I guess it isn't that important.

I took 8 oz of baking soda, spread it on a baking sheet and baked it at 275° for an hour, and ended up with 5 1/8 oz of what must be sodium carbonate. I noticed a fine dusting tended to float into the air as I poured, so I tried to not breathe it or get it in my eyes. Interesting. Now to make some pretzels...
Baking the baking soda at 275° for an hour

5 1/8 oz Sodium Carbonate

A comparison test of pretzel bath methods:
My latest pretzel recipe and techniques:

1 comment:

  1. for each NaHCO3 formula unit you get 1 OH-.
    for each Na2CO3 formula unit you get 2 OH-.

    Because of solubility, there is a limit to how much you can put in the water. If you put the maximum of each in the water, you get more OH- from the Na2CO3.

    It's a bit more complicated than that, but not much.