Sunday, February 2, 2014
Natural Yeast Used with Regular Commercial Yeast
The problem is that it doesn't raise the bread much. I like the taste, but I don't much like eating bricks. My natural yeast has always had a great bubble, but not a great rise. I worried about the start, but according Melissa Richardson, it's fine and should make a great loaf.
I've given starts of our natural yeast to people who are able to get bread that rises brilliantly, so clearly it's something about our kitchen here than is causing the trouble. Unfortunately, no one has volunteered to bake bread for us in a good rising kitchen and we only have the one poor rising kitchen, so we need to find a fix. And I know we are not the only folks who are having the same trouble with good yeast and a poor rise.
I did some reading and learned a bit more about yeasts and gluten and bread science. It's all a bit confusing. I thought I'd lay it all out here and let you guys chime in with what you know, too.
According to Caleb Warnock, who, along with Melissa Richardson, wrote The Art of Baking with Natural Yeast: Breads, Pancakes, Waffles, Cinnamon Rolls and Muffins, natural yeasts consume the gluten. This was true for us. I'd mix up the dough really well until it was nice and stretchy and then let it sit for a few hours to rise and come back to a wet puddle-y mess - exactly as if the gluten had been destroyed. I'd add more flour and give it another go and get....heavy bread.
According to The Accidental Scientist's Science of Cooking, you need the gluten to get a good rise. The gluten forms as a reaction between water and two proteins found in flour: glutenin and gliaden. The gluten forms long chewy strands. The yeast consumes the sugars in the flour and releases carbon dioxide - those bubbles are yeast farts. Bread rises when the gluten captures the yeast farts within the long stringy structures and holds them.
This is what I think is happening to our bread - the natural yeasts are breaking the gluten down and doing it well! But there's not enough gluten left to hold the bubbles for a good rise. It's healthy bread, but a poor rise.
So, Eric and I started thinking. Natural yeast is a collection of local yeasts. Commercial yeast is only one variety of yeast - a fast rising one and usually Saccharomyces cerevisiae. The makers of Fleischmann's Active Dry Yeast describe the process of growing this yeast on their site. What if we used the two types of yeast together? Why couldn't we get the health benefits of natural yeast and the good rise of commercial yeast?
Eric started by soaking the flours [we use mostly whole wheat] overnight in water with the natural yeast. We got a good soft flour with a very sour taste. We didn't like that. So, next Eric decided to soak only the flours in water overnight with no yeast. Then the next day he added both the natural yeast start and only 80% of the commercial yeast to the bread. If the recipe calls for 2 1/2 tsp of yeast, we only add 2 tsp. The mixture bubbles madly. That's what you see in the photo above. We consistently get a great tasting bread [with a lot of natural yeasts and all the benefits that come with them] that rises very nicely.
We are still experimenting with this approach. We're going to try lowering the quantity of commercial yeast and see how low we can go and still get a good rising bread. We'll keep you posted.