Reader Katie asks, since I live in Kentucky, if I’ve ever heard of salt rising bread and if so, could I tell her what it is. Katie, I certainly have heard of it. It’s a type of bread favored by Appalachian folk that’s leavened not with baking powder or yeast but with a bacterium that goes by the name of Clostridium perfringens.
If that name sounds familiar it’s probably because C. perfringens is a well known food pathogen, one that can and very often does make people sick, sometimes seriously so. That however doesn’t stop some people from raising their bread with it. Why? Because unlike just about every other microbe that can grow in a starter bowl (aside from yeast) C. perfringens creates copious amounts of CO2. The rise you get from it is every bit as good, maybe even better, than actual yeast.
People in Appalachia have made bread with it for hundreds of years. How do they not get food poisoning? Because as with yeast, the heat of the oven kills the bacteria, making the bread safe to eat. I’ve never made it because I’d never knowingly grow or work with a culture like that in my kitchen. I know of at least one bakery here in Louisville that makes it and for the life of me I can’t understand why the health department allows it. But people do strange things.
I bought some when I saw it for the first time because I was curious. It’s mild stuff for the most part, but with a vaguely cheesy flavor that comes from butyric acid, a by product of the C. perfringens metabolism. As longtime readers of joepastry.com know, butyric acid smells like vomit. Or parmesan cheese.
If you’re in the habit of making your own bread starter you may have encountered C. perfringens before, in the first day or two of your process. It often takes over the starter bowl at that point, but since it can’t survive in a high acid (or high-alcohol) environment for very long it usually dies off as yeasts begin to dominate the culture. That’s a good thing as far as I’m concerned, since as you can probably tell I’m no fan of salt rising bread. Hope that answers the question, Katie!