Friday, November 21, 2008

Mmmmm, chocolate :-)

I am quite excited this weekend that I get to try out a new chocolate cake recipe. This one is special in that one of its ingredients is sourdough starter. I think that makes it the geekiest cake recipe I've every baked :)

A sourdough starter is a mixture of flour and water, which has yeast growing in it. Back before yeast was available in handy little packets, starters were the standard way to leaven bread. Now most people find packaged yeast much more convenient. However you need a starter to get a traditional sourdough flavor, and that's what drew to them.

Those of you who know what sourdough bread tastes like, and what chocolate cake tastes like, are probably wondering how those two could have anything in common. The answer is in the lactic acid in the starter. Lactic acid grows right along side the yeast in a sourdough starter. They actually have a bit of a symbiotic relationship. The lactic acid metabolizes the maltose in the flour and water mixture. As it's churning through the maltose it produces glucose. The yeast eats other sugars, including the glucose! (The yeast produces alcohol... but trying to drink from your starter is not recommended ;) )

The lactic acid gives sourdough its distinctive flavor. It's also a great way to add acid to a cake. That in itself is not unusual. Many cakes use buttermilk or sour cream as one of the ingredients, not so much for the taste, but for the acid. The acid makes the cake more tender. This recipe uses sourdough starter for the same purpose. Once the sugar, cocoa, and other ingredients are added, the sourness should fade into the background, if not disappear completely. I'll find out which one this weekend! :)