Improve wording (#295)

This improves the wording of the sentence

book/history/sourdough-history.tex

@@ -90,10 +90,11 @@ \chapter{The history of sourdough}%
 were the reason the bread was better. It is not clear when
 they started using a bit of the dough from the previous
 day for the next batch of dough. But by doing so, sourdough
-bread making was born: Wild yeast in the flour and in the air
-plus bacteria start to decompose the flour-water mixture, also
-known as your dough. The yeast makes the dough fluffy, and
-the bacteria primarily creates acidity. The different
+bread making---as we know it today---was born: Wild yeast
+in the flour and in the air, with bacteria
+starting to decompose the flour-water mixture.
+The yeast makes the dough fluffy,
+and the bacteria primarily creates acidity. The different
 microorganisms work in a symbiotic relationship. Humans
 appreciated the enhanced airy structure and slight acidity
 of the dough. Furthermore, the shelf life of such bread