The Science Behind… enzymes


As I’ve mentioned several times in the past few posts, I’ve avoided touching on the subject of enzymes for two reasons.

  1. I didn’t really understand them, and therefore
  2. I didn’t think they were that important to breadbaking.  I figured food scientists probably cared about them, but that they aren’t really necessary for the lay breadbaker to understand.

After all, I’ve gotten this far without understanding enzymes, right?

It turns out, I was right on point #2.  You can get along perfectly fine without knowing a lick about enzymes.

However, once I started investigating enzymes, I felt like I understood bread in a whole new way.  The simplicity of flour, water, yeast and salt fell away as I discovered the complex chemical reactions taking place just under the surface.  The elegance of the various bread components and how they work together has been blowing my mind ever since.


me learning about enzymes

Ok, ok, enough teasing.  So what are enzymes?

In this post, I will address the following topics:

  1. What are enzymes and what do they have to do with baking bread?
  2. What are amylases and proteases?
  3. How can I use my new knowledge of enzymes to improve my baking?

First off, what the heck are enzymes anyway?

Enzymes are (according to the Internets) proteins that act as catalysts to speed up chemical reactions.  In baking, their primary role is to split apart starches, fats and proteins.  Without enzymes, both in the bread dough itself and in your saliva and digestive juices in your stomach, you would not be able to digest bread!


Enzymes can be found in yeast and flour.  Most of the enzymes at work in flour are activated by water, which is why the chemical reactions don’t take place in the bag of flour sitting on your shelf.  The enzymes move throughout a dough once water is added, and the higher the hydration, the better they move around.  So, not only does higher hydration contribute to bigger holes in bread, but the bread chemical reactions are more efficient too!

There are two main enzymes that are particularly important to bread – amylases and proteases. There are other enzymes too, but I’ll save them for another time.

The enzymes that break apart starches are called amylases.  Their role is to break up the starches in the flour into sugars that can be easily digested by the yeast.  Yeast are able to digest both sugars and protein, which is why amylase is so important.  If yeast do not have enough available sugars to eat, then they start in on the protein, i.e. GLUTEN.  We do not want the yeast eating the gluten, because it would destroy the structure of your bread.


Speaking of proteins, both yeast and flour also contain enzymes that break apart proteins.  These enzymes are called proteases.  There aren’t a whole lot of proteases in bread, but they are important.  By slightly breaking down some of the gluten strands, they give the dough a bit more flexibility and stretch.  Protease enzyme activity is controlled by adding salt.

Yeast also contains enzymes that break down the sugars into carbon dioxide and ethyl alcohol, but again, that’s a topic for another time.  In researching this post, it struck me how very many enzymes there are that contribute to the overall baking process.

A quick aside: the word ‘enzyme’ itself comes from the Greek enzumos, which means ‘to leaven from within.’ I think that’s pretty cool – a reference to baking is literally the origin of the word enzyme.

If you didn’t think enzymes were important before, that etymological factoid alone might convince you otherwise.

At this point, we know what enzymes are.  We know what amylases and proteases are.

How can we harness that knowledge to improve our bread?

The main way we can use our knowledge of enzyme activity is in increasing or decreasing the intensity of certain enzyme activity.  The various bacteria, microorganisms, proteins, sugars and fats work in symbiosis so it’s not always possible to control every chemical reaction, but by balancing the activity of certain enzymes, you can achieve a deeper flavor profile with sweet, bitter, sour, and salty.

For example, I’ve written already about inhibiting some of the amylase activity in rye breads so that there is still starch left in the dough to provide structure to the bread in the absence of gluten.

Lactobacillus acidophilus is a bacteria that inhibits amylase by increasing the acidity of the dough.  It’s present in sourdough starter and yogurt.  By using sourdough starter or yogurt in doughs, especially ryes that have a lot of amylase, you can slow down the conversion of sugars so the dough sets up properly when it is baked.

DSC03238Bowl and spoon with yogurt on white background, close up

Another way that we can use our knowledge of enzymes is in knowing how to properly store freshly milled and sprouted grain flours.  Regular all-purpose and bread flour do not have much amylase in it.  Freshly-milled flours and sprouted grain flours have lots of enzymes that get to work breaking down the fats, proteins and starches quickly.  By storing these flours in the freezer, the enzyme activity is slowed down and the flours stay fresher longer.

So, that’s The Science Behind… enzymes!  It’s not all there is to know, but it’s a start.  I hope you have found this post helpful.  As always, if something isn’t clear, be sure to let me know in the comments!


I had a lot of help writing this post from the following websites:

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