If you want to make a very sour loaf all you have to do is use well-ripened kefir [1] instead of water in the dough. Not only does this make the dough extra sou

If you want to make a very sour loaf all you have to do is use well-ripened kefir [1] instead of water in the dough. Not only does this make the dough extra sour, it also adds some extra raising power by virtue of the yeast in the kefir. For those who don't know, kefir is made by fermenting milk with kefir grains, a combination of yeast and lactic acid bacteria which forms a symbiotic colony. [1] https://en.wikipedia.org/wiki/Kefir https://en.wikipedia.org/wiki/Kefir