The Science of YEAST

Recently I’ve found myself looking at more and more natural ways and rather nostalgic ways of cooking and preparing food. And I mean like, nothing commercial about it-all from scratch-takes me a week to make one thing-nostalgic. From my point of view, good things in life are worth waiting for, and sadly, our modern-day culture wants everything as fast and painless as possible! What ever happened to caring about making QUALITY food? NUTRITIOUS food? Food we can be proud of and remind us of the complexity that is the living world around us???

This new found adoration of cooking in such lost and forgotten medias was spurred on first by what else but, Netflix… And by Netflix I actually mean the short series, “Cooked,” based on the 2013 book by Michael Pollan. The true story is that I watched the first episode of the series and pretty much decided then and there that I wanted to read the actual book and learn more about what he had to say about cooking as a manipulation of elements; Fire, Water, Air, and Earth.

In the chapter devoted to cooking with air, we can think of a few food products that depend on it, such as a meringue, a very similarly whipped cream, but especially BREAD. Bread is a truly miraculous food product! To think that we could make such a sweet, voluminous, and vital contribution to the diets of individuals across the globe and realize that we barely did anything to discover it. Who was the real inventor?????


Considering that the first “bread” was considered to be a rotten bowl of porridge that had began to bubble and was then fired out of curiosity (back in ancient Egypt), the only thing we seemed to do to make bread is assemble and bake! And for the most part, that stands true today. A simple loaf of bread is nothing more than flour, salt, and water. In this modern day-n-age you are likely to find a much more complex ingredient list on the label of your pre-sliced, grocery store loaf of bread. So what happened to this simple loaf of bread that was made by nature and nurture? According to Pollan, as we tried to develop more shelf stable foods and mass produce things during war-time, we started to shift from home made to easily accessible, ready to eat ones. The idea being that we should allow the commercial food industry to do the cooking for us so we have more time to better our lives with one less “hassle” on our hands.

As with most things in history, a great idea can get out of hand, and within a few decades we seem to have lost all scope of eating real food. Another one of these great ideas was the creation of Active-Dry Yeast. If bake any kind of roll, pita bread, pizza crust, etc, odds are, your recipe is going to call for this Active-Dry Yeast. The Idea being that rather than waiting 5 or so days to produce a natural yeast “starter” for your bread and then having to wait almost an entire day for the mass fermentation and leavening process, you can add a tablespoon of active dry yeast and see a significant rising of your bread in a matter of a couple hours! Great? Heck yes! Healthy? Ehhhhh….

The use of a natural yeast starter, such as that of a loaf of homemade sourdough bread helps add so much to the bread nutritionally. The key to such a bread is that the flour is actually being fermented. The bacteria that develops in a true sourdough starter is known as Lactobacillus sanfranciscensis. It gets its name from the bacteria that was onced believed to only develop in the bakeries of San Francisco when making sourdough bread. Assuming you are using a real, all whole grain flour, the fermentation of that grain allows us, as humans, to efficiently digest the bread, reap the benefits of natural fiber, and properly absorb the protein, carbohydrates, B vitamins, and other nutrients that sustain our lives! When using a bleached all purpose flour and active dry yeast, as is done in most commercial loaves of bread (and even most of the “whole wheat” loaves), we are not breaking down any of those grains very effectively for our body to gain the nutritional value we need. So while, yes, whole grain breads are lower on the Glycemic Index than white bread, and add a healthy portion of fiber to our diets, the nutrients in a commercial loaf tend to be inaccessible to us. So to sum things up visually;

Naturally fermented, whole-grain bread > Commercial whole-grain bread > white bread

If you want to find a good recipe for a naturally fermented, whole-grain bread, check out Michael Pollan’s book, Cooked, A Natural History of Transformation. It will be much more time consuming than making a generic loaf of bread, but this is really a process that has been done for ages all over the world, and is really worth it in the end.

By: Sam Martinez, DTR

Purdue University ’15

Cooking Instructor



One Comment Add yours

  1. Katie says:

    Awesome blog!! Keep it up!! 🙂


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