Improve text for enzymes (#435)

* Improve text for enzymes

ajes from Discord pointed this out. Improvements by Cookiedust. Thanks!

* Add PR feedback

* Fix --- use, hopefully

book/basics/how-sourdough-works.tex

@@ -75,12 +75,13 @@ \subsection{Amylase}
 Normally,
 the microorganisms on the surface of the grain can't consume the freed maltose
 molecules, which remain hidden inside the germ. But as we grind the flour, a
-feeding frenzy takes place. Generally, the warmer the temperature, the faster
-this reaction occurs. That's why a long fermentation is key to making great
-bread. It takes time for the amylase to break down most of the starch into
-simple sugars, which are not only consumed by the yeast but are also essential
-to the \emph{Maillard reaction}, responsible for enhanced browning during the
-baking process.
+feeding frenzy takes place.  Generally, the warmer the temperature, the faster
+this reaction occurs. However, it takes time for the amylase
+to break down most of the starch into simple sugars---which are not only
+consumed by the yeast but are also
+essential to the \emph{Maillard reaction}---responsible for
+enhanced browning during the baking process.
+That's why a long fermentation is key to making great bread.
 
 If you're a hobby brewer, you'll know that it's important to keep your beer at
 certain temperatures to allow the different amylases to convert the contained