Geek’s Corner: Cold Fermentation vs. Epoxy

I’ve been having some fascinating discussions with a few readers via email, all about Peter Reinhart and the evolution of his whole wheat sandwich bread recipe. The conversations began when three readers alerted me to the fact that Reinhart updated his recipe in his most recent book, Peter Reinhart’s Artisan Breads Every Day. Essentially, he converted the recipe from his so-called “epoxy method” which calls for a starter and a soaker, to an overnight cold fermentation method along the lines of the pain à l’ancienne recipe over to the right. It’s a bit surprising, but it makes all the sense in the world when you consider what the epoxy method was initially designed to achieve.

Though I don’t know exactly why Reinhart calls the epoxy method the “epoxy method”, I presume it’s because like epoxy, which combines two separate elements (a resin and a hardener) to produce glue, his method combines two elements (a soaker and a starter) to produce bread dough. The question is: why do that? Well, as I’ve often discussed here on the blog, slow-rising doughs are the ones that tend to have the most flavor. The reason for that is two-fold. On the one hand, the longer fermentation gives flavorful lactic acid bacteria time to grow. On the other, it gives enzymes in the flour more time to work, chopping down long-chain starches into sugars.

The epoxy method divides those jobs among two separate bowls, one of which combines flour and bacteria-rich milk (or buttermilk or yogurt) and is left to ferment at room temperature overnight to encourage bacterial growth. The other bowl contains flour, water and yeast, and is refrigerated overnight. What the refrigeration? Because yeast grows very well at room temperature and will consume virtually all the starch in the bowl if left out at room temperature. Enzymes, on the other hand, will work quite happily at refrigerator temperatures, making sugar through the night while the yeast is “asleep.” In the morning the two bowls are combined to create the finished dough.

It’s a great idea, though perhaps not necessary when you consider that some lactic acid bacteria will continue to grow in the fridge, if not to the extent that they would at room temperature, at least enough to give the bread a decent flavor. That being the case, why not just mix the dough all at once and let it ferment in the fridge overnight? That’s the conclusion that Peter Reinhart arrived at, so he says, after overcoming his suspicions about the “no knead” breads that have been all the rage the last few years. I give him an awful lot of credit for having the strength of character to reevaluate his convictions in that way. To emerge as he did from the hyper-ideological 60’s and 70’s-era artisan bread movement, then go on to embrace innovation the way he has, well, not all of us would have that sort of courage. Reinhart is clearly prepared to follow wherever the pursuit of great bread takes him, and you have to admire that.