I've been playing around a lot with mash bread and wanted to share my thoughts and hope some other people might want to give it a try. For those who aren't familiar with mash bread, Peter Reinhart's Whole Grain cookbook discusses it. The essence is taking flour or grain and cooking it with water at around 150 degrees for a few hours to get the enzymes to convert starches to sugars. He uses flour and spent grains for mashing and then adds it to bread for a great addition of flavor and complexity. After looking further into the mashing process, it is very similar to brewing beer. When brewing beer, brewers take sprouted grains, cook them at a low temperature in water so the enzymes can convert starches to sugars. The sugary liquid is called wort. The wort is then fermented and the yeast eats the sugar converting it to alcohol and beer is born. So, I thought, how can we use that process or part of it for bread making? Reinhart says there are very few mash bread recipes around and he's right. So, I thought I'd add my experiences to the small pile.
I love the purist concept of the baguette, using only flour, water and salt. Well, here is another grain manipulation that can create sweetness without any additional ingredients. Since rye has one of the highest level of enzymes, I went with whole rye grain. It produces the greatest amount of sweetness in the shortest amount of time.
Soak the rye grain in water overnight. Then, drain the water and keep the grain moist. In 36-48 hours, it will have sprouted and grown to its enzyme peak. The sprouts should be 75 - 100% the length of the grain. I then grind all the sprouted rye in a food processor. I then measure water at double the volume of the grain. Heat the water to 165 degrees and add then grain. Then cover it and put the pot in the oven at 150 degrees for 3 hours.
What you get is a sweet, watery grain slurry. Reinhart would call it mash, some might call it wort. The key here is that the grain is not "spent" from the beer brewing process. You get the enzymes to work for you for the bread making. I believe Reinhart uses more water than I do, but I have found 2x the volume of grain to be plenty. I let the mash cool and then use it exclusively as the liquid in a bread recipe. Wheat berries will produce a similar effect but will take a bit longer to sprout.
This is where things get a bit experimental. Do I have exact measurements and a recipe yet? No. I'm going entirely by feel of the dough. What you will find is that the dough will be stickier than usual. You will want to judge the dough more by its density than by the feel of stickiness.
I have made breads with both white flour and 100% whole wheat. With white flour, you will get a complex, sweeter taste with a moist crumb. It reminded me in sweetness of the soft Hawaiian bread you can buy in the stores. With 100% whole wheat, you get the sweet complexity, a moister crumb and you can eliminate the typical addition of honey or agave or sugar.
This has been a very interesting way to add sweetness and moistness to bread without additional ingredients. It's just grain, water and salt. For those who love to take a long time to make a loaf of bread, instead of a three-day bread, add this to the mix and it will take 5 days to make a loaf due to the time of sprouting the grains. You can also make a lot of the mash as it freezes well and you can put into single-use containers.
I hope that provides enough explanation to get people going. Feel free to add your own experience with mash bread, ask questions, etc.