Friday, December 7, 2012

The Biology of Bread Making

The process of making bread is an extremely biological process.  Good bread bakers are experts at controlling the biological processes involved in making delicious bread, even if they don't know it.  There are two major biological components to bread, first is the wheat flour and specifically gluten, and secondly the yeast.  A typical bread recipe is very simple and includes water, sugar, salt, wheat flour, and yeast.  All of these ingredients work together to create an environment for the yeast that creates bread.  I will explain each of these components and discuss how they can create the ideal bread making environment.

First we will talk about sugar.  Sugar is very easy for yeast to consume and therefore helps the dry yeast off to a quick start.  This helps the yeast to quickly start growing and reproducing, causing the bread to rise.  Yeast also can consume the carbohydrates in the wheat flour, but these are harder to consume.  Depending on how much sugar is added, the yeast will normally consume all of the sugar in the dough.

Water in the bread making process is not extremely interesting.  It is of course a requirement for all of life and without it the bread would never form.  In bread making tough it is important to balance the amount of water to the amount of flour to get the right consistency in the dough.

While sugar helps speed-up the reproduction and function of yeast, salt slows it down.  By balancing the salt and sugar in the dough recipe we can balance the growth of the yeast, not too fast and not too slow.  Without salt, the dough would rise too quickly and collapse.  With too much salt though the bread would rise extremely slow. 

Wheat flour of course is what actually composes the bread.  I say wheat flour specifically because wheat is the only type of flour that contains the protein gluten.  Without gluten the flour would not rise into a spongy loaf of bread but rather would turn into a dense heavy mass of cooked flour.  Gluten is a long sticky molecule that sticks to other gluten molecules.  This allows the yeast to form air bubbles in the dough, making it rise.   Gluten molecules stick together, making the flour in the dough to stick to itself so it can rise.  Without gluten, bubbles couldn't form and the dough would not stick together and the dough would not rise.  Flour also provides carbohydrates for the yeast to grow and function.

Lastly, yeast produces carbon dioxide that helps form bubbles in the dough, making it rise.  As yeast consumes sugars and carbohydrates it releases carbon dioxide.  Without the carbon dioxide produced by the yeast, the dough would not rise.  Yeast functions best at warmer temperatures so more time is needed for bread to rise when temperatures are lower.  When you finally bake your bread, the high temperatures of the oven actually kill the yeast and solidify the gluten and dough structure.   Baking ends the biological processes of bread making so it is ready to eat.

A lot more can be said about the origin of yeast and gluten as we find them in our breads today.  But the above are the essentials of the biology making bread.  Knowing these things can greatly aid your ability to come up with your own recipes and make the perfect bread.  Using the above, you can also come up with your own scientific process or experimentation in bread making by varying water, sugar, salt, and yeast amounts.

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