Once while on vacation in the Midwest we were driving along the interstate when a field of wheat came into view. I'm an east coast boy, and though I've been an avid baker for quite some time, I'd never actually seen wheat growing. It was a veritable sea, sort of ebbing in the wind. I asked the driver to pull along side the road so I could go into the field; I had to. I only walked a few feet into it, but with my back to the road all I could see was wheat, it was as if I were engulfed. After a few minutes of unconsciously brushing my hands along the tops of the swaying plants, I reached down and grabbed a handful and brought them with me. Later in my home kitchen I husked the tiny kernels, and using a coffee grinder, ground them into flour. It only yielded a few tablespoons of flour, but still I was in awe. Flour is simply that: the ground kernel of the wheat plant. The main difference between white flour and whole wheat flour is that whole wheat still has the bran, or shell, and also sometimes the germ, ground with the endosperm. White flour, on the other hand, is mainly the ground endosperm, which is what constitutes most of the kernel.
Flour is the largest ingredient by volume in bread, and the type of flour used will determine the nature of the resulting loaf. Many types, even those not derived from wheat, contain gluten, but wheat flour contains the highest percentage. Gluten is a natural occurring protein and provides both structure and flavor to the dough (think of gluten as sort of like the "muscle" of the dough).
Flour types are defined by the amount of gluten, or protein, that they contain. The more gluten, or the higher the protein percentage, the "stronger" it is. Bread flour, for example, has between 12 and 14 percent gluten, this is necessary to create an airy, chewy, and crusty loaf. Cake flour, on the other hand, which is one of the weakest flours, usually only has about 6 or 7 percent gluten. This is because unlike breads, the thing that makes cakes and pastries so delicate is their tenderness, and this is achieved by using flour with low protein. The median of these, of course, is all-purpose flour, which has about 8 to 10 percent gluten. But in following the old adage of using the correct tool for the job, the same can be said for ingredients. Thus, when baking bread, bread flour will give you the best results, but in a pinch I have used all-purpose.
Another consideration is the brand of flour, because they do vary somewhat, and this will undoubtedly be a personal preference. There are many brands available that are high quality, but the thing to really look for is flour that is neither bleached nor bromated. Bleaching and bromating is totally unnecessary (and in some areas of the world deemed illegal and considered carcinogenic). All this does is make the flour as white as new fallen snow. Unbleached flour whitens naturally as it ages, but it has a more natural creamy white tint to it, and in this baker's opinion, a more attractive one.
Water is the next ingredient by volume used in bread making, and it's such a ubiquitous one that in some antiquated cookbooks it's actually left out of the ingredient list, assuming that everyone simply has it. But it's also an integral ingredient, especially when making bread. It's interesting, because without the addition of water flour does not contain gluten. Protein is present but gluten is not developed until water is absorbed into the flour and its molecules swell and are kneaded; gluten develops much in the same way a body's muscles do with repetitive weight resistance. When dough is kneaded, strands of gluten align and connect, creating longer and stronger strands (and to go off on a slight tangent: this is also why vegetable shortening is called shortening, because it inhibits the gluten strands from connecting easily, thus shortening them and creating a more tender dough, as is the case of pie dough, and for this same reason certain doughs that have a high ration of fat are called "short doughs").
Water is also the catalyst for yeast activity. For without water yeast remains dormant, and after a certain amount of time will actually perish. But with the addition of water yeast comes to life as if a spring breeze blew in and brought it out of hibernation. You may hear some bakers claim that the secret to their bread is not in their technique, flour, or oven, but is actually in the water they use (and this may be true in some cases). I believe, for home baking, if your water is drinkable it's fine for making bread.
The proportion of water-to-flour ratio will drastically affect the outcome of the bread. The higher the water content the softer the dough and the more fermentation activity between the water, yeast, and flour, thus larger pockets of air in the dough. This yields not only a more rustic looking bread, but a more flavorful one as well. If dough is too soft, on the other hand, it may be difficult to work with. And a dough that is too dry may be difficult to knead and will yield a "tighter" bread, or one with smaller and more consistent air pockets. A good general ration is 1 1/4 cups water to a scant 3 cups of flour. This will make a dough that is soft enough to yield a course and fermented bread, but at the same time one that contains enough flour that it will be easy to work with in its raw state (if it is a little sticky you can dust your hands with flour).
The temperature of water will also affect dough. If water is cold it will inhibit fermentation and yeast production, and thus may seem as if the dough refuses to rise. The fact is that a slower, colder fermentation, one where the bread is allowed to rise over a longer period of time, produces a far superior loaf of bread, and it's these things that will come to you as you become more adept at baking.
Water that is too warm, on the other hand, can have truly adverse affects on the dough. Firstly, it may make it rise too quickly, where the dough would be "young" when it went into the oven, one that hasn't endured enough fermentation. And even worse, if water was actually hot it could kill the yeast. Water that is room temperature is usually the best measure.
Yeast is easily the most interesting ingredient in bread making, or at the very least the most misunderstood. It's sometimes viewed as a sort of hit-or-miss ingredient, as if it's uncontrollable. But this thought couldn't be more wrong. This same way of thinking, one where bread making is viewed as a sort of gamble, where the bread may or may not come out well, or it may or may not rise, has often lead to an actual fear of bread making. And like many fears, this fear is merely a form of ignorance, of not understanding something. It has been my experience that it would be more difficult to create bread that did not rise, than one that did.
This fear, or more specifically, worry, that the bread will not rise, undoubtedly springs from many things. And one, I think, is the use of the word proof, as in proofing the yeast, and proofing the dough. Use of this word stems for the early days of commercial yeast production when it was not always reliable. At that time it was necessary to hydrate the yeast with a little warm water to proof it, or to allow the yeast to prove to you that it would indeed become active. The same can be said for "proofing" dough. The use of this word is really no longer relevant, though many bakers, including this one, still use it. More appropriate terminology is to activate the yeast, and ferment the dough. Unless yeast is exposed to extreme temperatures, or used beyond it's expiration date, the chances of it not becoming active are slim to nil.
There are three common ways in which yeast is marketed: fresh compressed yeast, active dry yeast, and dry instant yeast. All forms work well, but they do so in different ways. Fresh yeast, which is sold in small one-ounce cakes in grocers but in one-pound bricks to professional bakers, is often called baker's yeast because many professionals favor it. Fresh yeast is also relatively hydrated (something like 70 percent moisture, whereas dried yeast is around 8 percent), and for this reason it makes it more perishable and less consistent to the home baker. And also because of its hydration, more fresh yeast by weight is required to do the same job as dried yeast. Dried yeast is more consistent and easier for the home baker to use, but which one to use may fall into the category of personal preference.
Active dry yeast has to be dissolved in water prior to mixing, whereas dry instant yeast can be added directly to flour or dough. Dry instant yeast is sometimes labeled as "fast acting yeast," or "quick rising yeast." These are actually misnomers because it's not that the yeast will actually raise a loaf of bread faster (which isn't always a good thing anyhow), but it's that instant yeast contains more living yeast cells, about 25 percent more some say. Thus, while both forms of dried yeast look similar (although the instant variety has much smaller grains), when the same amounts of each are used you are actually adding 25 percent more via the instant variety. Personally, I alternate between using regular active yeast to instant yeast, and I've found both to offer excellent results.
The interesting thing about yeast, almost unbelievable, really, is that it's a living single-celled microorganism, albeit dormant in its dried state. Fermentation, or aging of the dough, occurs when yeast and flour are hydrated and yeast becomes active and feeds on sugars, or carbohydrates that are converted into sugars, that are present in the flour. When yeast eats it produces byproducts, mainly alcohol and carbon dioxide, which occur in the form of gases. This is what gives rising bread its distinctive aroma.
Now here's the really cool part. When yeast emits gases they rise and attempt to push through the dough, which inadvertently forms tiny air pockets. Some of the gas does push up through the dough, and this adds flavor and character, but the pockets themselves, which are a sort of non-ingredient, are really integral. The little pockets of trapped gasses eventually begin to swell, which also stretches the flour, which in a way is kneading the bread on it's own, and when the pockets get bigger the dough of course gets bigger. And this is how bread rises.
Salt is the last ingredient that is necessary in bread making, and though added in small amounts, this is an ingredient not to be underestimated in purpose: salt does much more than flavor bread. To pose an analogy, think of salt in bread making as to what a bass player is to a quartet: the bass player keeps everything in check. If the bass is too loud or too much in the forefront it is distracting, but if it is too low the sound is hollow and tinny. The bass player keeps the whole band in rhythm, just as salt keeps the entire fermentation process in proper rhythm.
Adding saltiness to bread is actually salt's minor role, more importantly it acts as a controller. It inhibits yeast activity thus slowing down fermentation, which adds more breadth to its flavor. Bread can be made without salt, but the whole process would be out of sync. Without salt yeast would consume it's food too rapidly and the bread would rise too quickly. When this happens bread tastes flat and yeasty. Salt also effects the development of a crisp crust, which has a direct effect on shelf life.
Salt, of course, is available in many forms. Some bakers prefer seas salt; I tend to use kosher salt because that's generally what I cook with so that's what I have on hand. All salts perform the same action, and I really doubt that even the most discriminating palate would be able to ascertain which salt were used in a loaf of bread.
Besides the aforementioned ingredients, which are necessary ones, there are many others that can be added to bread. Some are common, such as fats and sugars, and some are not-so-common, such as vegetables or even dried fruits. Here are just a few of them and how they'll affect the bread.
Different types of flour: Simply changing a portion of the flour with that of another is one way to change the type of bread you make. Generally speaking, bread is usually based on bread flour, with the option of replacing a portion with another type of flour, such as whole wheat, rye, etc. Whole-wheat flour is the most common choice. Bread made with whole-wheat flour will be more nutritious and flavorful. But bread made entirely of whole-wheat flour will most likely be heavy. The same can be said for rye or pumpernickel flour. A ratio that I like to use is 2-parts bread flour to 1-part other whole wheat or rye flour.
Fat: Any fat that is added to dough will change its texture because it shortens the gluten strands. It will be softer and more flaky and tender, such as traditional sandwich bread. Because of the lasting effects of fat, it will also keep bread softer longer, thus in a way keep the bread fresher longer. Though eggs are technically a protein, they can also fall into this category. They too will yield softer flakier dough.
Sugar: Besides yeast, sugar is probably the most misunderstood ingredient when making bread. There is a misconception that it is added to bread to feed the yeast. While yeast does thrive on sugar, always remember that flour and water produce enough food for yeast to grow, and bread will have its own subtle sweetness. Notwithstanding, sugar does have its place in bread making when used in small amounts. This too is often used in conjunction with fats. Besides the sweetness that sugar adds, it also has some preservation properties.
Plenty other ingredients may be added to bread dough with various results. Vegetables and cheese, for example, are excellent options. Adding different ingredients to dough is a great way to experiment, and also one that keeps bread-making fun.