As a professional baker it is strange to me why anyone would want to know the true chemistry of bread making. I have never met a scientist that bakes, and if I did he would probably give me some reason why we shouldn’t eat bread. Fresh baked bread smells so good and tastes even better; there must be something wrong with it at a molecular level to make it bad for us.
Now, if you want to understand what is behind the making of good bread, well that I can explain to you in simple laymen’s terms. There is no need (or desire on my part) to go into complicated explanations and formulas you would never understand anyway. So following with the KISS (keep it simple, stupid) formula I will do my best to inform rather than bore you.
Basic yeast bread such as French or Italian bread is composed of 4 ingredients, flour, water, yeast and salt. More complex breads like the ones we know in North America also contain shortening, sugar and sometimes milk.
Something called a leavening agent is needed to make bread rise and fill it full of the little air pockets. These air pockets make bread light and fluffy. In the case of yeast breads, yeast is the leavening agent.
In Ireland they make soda bread which uses soda and not yeast to rise. Here in the Americas we also use soda and baking powder as a leavening agent which makes biscuits, cookies or cakes rise. Simple, a leavening agent is something that makes things rise. None of these leavening agents however can work alone. They all need to be mixed with moisture first plus heat or acids in the case of baking powder or soda.
In the case of bread it is most often water that gets mixed first with the yeast. So now we have our yeast in the water and it starts to bubble. What causes the bubbles is a by-produce of yeast being a living organism. Let’s just say that as the yeast grows and multiplies it releases what we all do after we eat, gas. Yeast produces alcohol and carbon dioxide gas.
So our yeast is now alive because we put it in water and given it an environment to grow in. We need to capture that gas it is producing so we can use it in our bread. We also have to feed the yeast to keep it alive and multiplying. This is where the flour comes in. If we mix yeast and water with flour we can provide the yeast with food. It can eat away at small amounts of flour and continue to grow and really multiply. In the case of bread, the more yeast growth the better because it will produce more gasses and some extra flavour.
It is important to know at this time that there are several types of flour used in baking. There is a protein in flour that when wet, produces small strands that can’t be seen. We call this protein gluten. Gluten joins together and forms long strings that get wrapped around each other. These strings are what makes bread strong enough to hold in the gasses that yeast produces. If all the gasses got out you would have a thick heavy bread like a flat bread.
Certain flours have almost no gluten. These flours, we call them cake and pastry flour, are great for making flaky treats. Bread flour is made from a type of wheat that has lots of gluten so it is made into all purpose or even specialty “bread” flour. Whole wheat and rye flours have only a little gluten so we often need to mix bread flour with them so they rise well and stay puffier during baking.
Now our bread has water and yeast and flour for food and structure. This is enough to make the bread rise fast. Now we must add a little salt. Yes, salt is good fo flavour, but it also kills some of the yeast. This is good because bread would rise too fast and not bake well if it wasn’t kept under control, so we add salt. This simple recipe up to this point would produce a good basic French bread.
Here in North America we like our bread to last longer than a day and we like it a little richer than French bread. By adding milk or milk powder to the dough we add lactose, a type of sugar. As you know when sugar is heated it will brown. The lactose in the milk will give our breads crust a nice color and add a little bit of flavour. Likewise sugar will help feed the yeast and speed fermentation (yeast growth) while adding a little sweetness.
So what does the shortening do? Some bakers believe (as I do) that shortening lubricates the bread as it rises so it rises better. Shortening will also stay in the bread after it is baked and keeps it feeling moist. Oils won’t evaporate like water. It also adds taste and something we call a nice “mouth feel”.
Now we come to that thing they call kneading. After bread is mixed we need to knead it.
Kneading is the action of pressing the dough between the board or table and our hands. You can knead in a mixing bowl with dough hooks or simply pick the dough up and slap it down on the table. The more you knead the dough the more strands of gluten you create.
Remember, we want our dough to be able to be strong enough to hold in all the gasses the yeast produces. After we knead the dough we cover it and let it rest so the dough can relax and the yeast can work. After a while the dough will fill with carbon dioxide and alcohol. Both these items will kill the yeast or slow it down so we “punch” out the dough to get rid of the excess.
Finally the bread is ready to be rolled into loaves. We punch the bread down once more and form it into a loaf. The bread is allowed to proof (puff up) one last time.
Just as the bread gets about 80% of its full puffed up size we pop it in the oven. The heat will make the bread rise very quickly. A crust will form on the outside of the loaf and get hard enough to hold the gasses in. Heat will kill all the living yeast, evaporate most of the carbon dioxide and all of the alcohol. The bread will set and before you know it, the inside will bake into a milky white sweet smelling loaf.
Now you know the inner workings of bread baking. Easy stuff once you know how it works and handy too. Next time you make a nice pie or some muffins for breakfast and they turn out a little tough, you will understand why, gluten. So go ahead and practice, be gentle with your pastries and beat up on those breads. In no time you will become an excellent baker.