During the rising process, the yeast feeds on the sugars in the flour. The most important by-product is carbon dioxide, which causes the bread to rise as it is trapped inside the dough.
First, the ingredients are mixed together and left alone so the yeast can work on the flour. At the end of the rising process, the CO2 is liberated from the dough (usually by what is called "punching down"). The bread is formed into loaves/rolls and left to rise a second time. It is then baked. Although the baking process contributes to the "rising" of the bread, most of the leavening is the result of yeast activity.
Yeast comes in a dried form and is brought back to life when water (or another liquid) is added. The re-hydration process is temperature-sensitive. If the water is too hot, the yeast will be killed.
Note: Yeast also comes in a moist form, but you have to use this immediately after the production date, so don't bother with this kind.
Most breads rise twice: once before loaf formation and once after. With each successive rise of the dough, the yeast gets a little more tired, and the sugars are used up. This results in less and less CO2 production and hence formation of fewer air pockets in the bread. Therefore, the more times the dough must rise before baking (such as with pumpernickel, which requires four rises), the denser the texture of the bread.
Breads made without yeast (entirely unleavened; or leavened by baking powder - - which is a chemical reaction rather than a fermentation) are denser than breads made with yeast.
Not only does yeast affect the finished bread, but so does kneading. A coarser texture is produced if the bread is not kneaded. Therefore stirred yeast breads will be "more rustic" than kneaded breads; that's the trade-off!
How re-hydration is done is important to the finished bread. Recipes usually say "warm water" and "lukewarm water," but sometimes they just say "water" and you're supposed to know. Water should be a lukewarm-comfortable, hand-washing temperature, about 80° to 85° (not a hot-water-comfortable hand-washing temperature).
If you scald milk or melt butter or raise the heat on anything to higher than lukewarm, you must let the liquid cool to lukewarm before adding to the yeast or you'll kill the yeast.
Yeast, when re-hydrated, "grows" very quickly, especially if you have added a T of sugar to the water to give it a boost. Kids love to watch yeast "blossom" and smell it working. (Don't add salt at this point; it retards the initial growth of the yeast.)
Most always, the recipe directs you to mix water (or some other liquid) with the yeast and let it "work" ("blossom" thoroughly). Sometimes the recipe says to let the mixture sit "until bubbly" (this is called making a "yeast sponge"). It's all the same thing, no matter the terminology.
Note: A few recipes (usually called something like "quick-rise") have you throw everything together, wet and dry, yeast, and other ingredients. It is always more reliable to mix the yeast and water first and let the yeast get a head start.
Count on 1 T yeast per batch of bread. This is the approximate amount in one of the little packets. If you really get into breadmaking, you'll end up buying yeast in bulk and measuring it out.
Yeast, does have a shelf life, though. You usually can get away with some time after the "expiration date" printed on a yeast packet (less than a year). If it's been a while since you used your bulk yeast, buy some fresh and put a little of it into some warm water with a bit of sugar into the old and see what happens. Maybe nothing! If so, you have the fresh yeast on hand.
Don't count on having fresh bread today unless you -know- you have working yeast! Or you -know- you have yeast dated no more than three-to-six months past the expiration date.
Other leavening agents that are used in breads: eggs, baking powder/soda, sourdough starter.
Because you're going to have variability in the flour department is another reason to give the yeast a head start.
The best flour for breadmaking is "hard" (durum) flour because it has a high gluten content. This is the same flour that is used in making high-quality pasta. Most stores also have "bread flour." If you have a choice, buy this. I have made a lot of bread from normal cookie-and-pancake-making flour, so if your store doesn't have "bread flour," don't worry.
Gluten is a collective term for mostly-protein molecules. Gluten is found only in wheat. A high gluten content in bread-making flour helps bread withstand the ravages of CO2 trapped inside the loaf during the rising process (more below). It also contributes to the flavor and texture of the bread.
It's best to see someone do this (or look at some drawings), but the basic process of kneading is to draw the dough into a ball and (on a floured bread board), push it away from your with the heels of your palms. This causes the dough to become cylindrical after five to six pushes. Give it a 90-degree turn, fold it in half, and push it away from you again. Turn and fold whenever necessary.
Sometimes the recipe calls for, say, 5 c flour, and you cannot stir in that much. Knead in the rest (if it will all go). Actually, you're likely to need more flour than 5 c, depending on the dampness of the flour, the day's humidity, etc.
Although my mom uses a wooden board, I have always kneaded my dough right on my countertop. (When we moved to California, the builders' spec lists at the time gave everyone ceramic tile countertops, which meant low spots where the grouting is. This is a mess to clean after breadmaking, so I bought a big plastic cutting board. (You may need to saw off some of it to make it fit in your dishwasher.) Because this board slides around on the countertop, I then bought some RubberMaid (I think) non-skid stuff; comes in a roll and looks like webbing. I cut a piece a couple inches smaller than the cutting board. (The non-skid probably will be more narrow than the board, but this doesn't matter a whole lot.) I set the cutting board on the non-skid when it's time to knead. Works really well! I roll up the non-skid and store it in my silverware drawer after breadmaking. (If you have read my cooking disasters file, one of which is about hard-boiled eggs, it is this rolled piece of non-skid in the silverware drawer that generated part of the bliss.) You also can roll it up loosely and run it thru the dishwasher.
A wet towel works nearly as well as an anchor for a slide-y bread board.
The problem with gluten, though, is that it sometimes makes your dough un-cooperative. For example, when you're rolling out pizza dough to extend to the sides the pan, you find that as you roll the dough it springs back! This recalcitrance is because the gluten molecules are still holding hands, so to speak. Let the dough rest 10 minutes so the gluten can "relax" and then try again. During the rest, cover the dough with a towel to prevent formation of a dry crust on the outside.
This is a good time to prepare the rising bowl and baking pans/sheets.
When kneading directions say something like, "Knead until smooth and elastic," the "elastic" part of it refers to the formation and development of the gluten: the dough doesn't spring back but stays the shape you want.
Note: After I dump out the dough onto the counter, I wash the bowl so I can use it again as the "rising" bowl. Maybe you have two big bowls!
After kneading the dough, place it in the oiled bowl and turn it over so an oiled surface is up. This oil sheen keep a dry crust from forming on the top of the dough as it rises.
Cover the bowl with piece of Saran Wrap (spray with Pam) and a clean tea towel.
Put the bowl in a warm place so the dough can rise. Where?
Ha! You have to find the best place in -your- home for this. The ideal temperature is 80o-85o. The lower the temp, the slower the rise. (French bread prefers 70o-75o. And there are many recipes for an overnight rise in the refrigerator, and that's right cold.)
Usually ambient room temperature is not warm enough to get much action before the dough starts to change character. A very long rise at room temperature, for example, will produce a sourdough bread! So, try to find a place that's warm enough to do the job in 2 hours or so.
In college, I used the top of my hot water heater. Never found anyplace better. It was located in the linen closet, so I could keep it clean. Nowadays my water heater is located in the garage, so I have to find other places to let my dough rise.
Option I've used: (1) Turn the oven to "warm" and then cut it off, leaving the door ajar. (2) Put the bowl in the oven with the oven lightbulb lighted and close the door. This is enough warmth. In any event, I monitor the temp. I want 80o-85o. Good excuse to buy a gadget: oven thermometer!
If you use the oven, make sure the rack is low enough so that when the dough rises (doubles in height) it won't get all over the underside of your oven. (Guess how I figured out this warning?! Did I mention there were broiler elements involved?)
The dough will double in size (or the recipe will say whatever another proportion is). The yeast is releasing the CO2 as it works on the sugars and the mass will become riddled with pockets of trapped CO2.
How do you know when the dough has doubled in bulk? You remember what level the dough reached in the bowl when you put it in to rise so you'll have a good idea when your dough has doubled. A lot of people mark the pre-rise level with a pen in the bowl. Or use a large calibrated bowl (then, too, you have to remember!).
If you can't remember, use the "finger-stick method": poke your finger in the dough about 1/4" to 1/2" deep. If the dough springs back, it isn't ready yet. (The gluten is still too excited.) If the dough stays pushed down where you stuck your finger, it's ready. (The gluten is ready to play nicely.)
Turn out the dough and knead again. You doubtless will need more flour to take up the "liquid" of the oil and any other stickiness which has been created during the rise. Knead until the dough is no longer sticky, but don't over-do the addition of more flour; you don't want your bread tough.
Form the rolls, loaves, etc. and put them on prepared sheets (see below) and leave them to rise a second time, covered by the towel (lightly floured if you think it might stick to the rising loaves - using Pam in this step is not recommended).
Check on your dough half-way through what you estimate to be the entire second-rise time. Re-adjust time, as necessary. Over-rising is not a good idea; it will not make your loaves "taller" and more beautiful during baking. If the dough rises too much between formation and baking, your loaves will be misshapen and -won't- rise much in baking.
Cookie sheets can be sprinkled with corn meal or sprayed with Pam. (I do the latter.)
I do not rely on a non-stick pan or sheet's actually being non-stick. I call my friend, Pam.
To make your loaves look golden, very gingerly so you don't deflate the loaves, brush tops of loaves with beaten eggwhite. (I have also used a whole egg.) In my college days I often melted oleo or used oil since I didn't have an extra eggwhite sitting around and I couldn't conceive of throwing away the yolk to get the white! (Still wouldn't do this! So I give the egg a little stir so it won't explode and microwave it. I eat it or deliver it to joyous poodles.) If you want to sprinkle poppy or sesame seeds on the crust, this is the time to go it. Brushing with eggwhite (or whatever) will create a softer crust on the finished loaf, but it will be wonderfully brown and beautiful. You can brush on the eggwhite or oleo/oil in the last 10 minutes, too.
Another thing that affects the crust is humidity (steam) in the oven during baking. You can put a pan of water on a lower shelf (make sure there's enough water that it doesn't boil away during the bread-baking; ahem. And start with very hot or boiling water to begin with!). Preheat the oven for 400o and set the pan of boiling water in on the lower shelf. Let the oven return to 400o. Bake bread on the upper shelf at 400o for 10 minutes and then reduce heat (try 325o - you'll have to wing it here, based on your oven - if, after 10 minutes, 325o doesn't seem like it's enough, up it to 350o).
You can open the oven periodically and give the bread and the heating elements a squirt with a squirt-bottle of water (once every 10 minutes or so). The problem here is that you lose oven temp every time you open the door.
If you want a crisp crust, this is a challenge! (Read Julia.) Over the years, I've baked directly on pre-heated red quarry tiles, in specially-designed baguette pans, and used all sorts of techniques and paraphernalia. Sometimes the same methods don't produce the same results! Surprise!
Brushing nothing on the top of the loaf and using no steam seems to produce crisper crusts for me. Sometimes, though, a periodic water squirt helps. A good French bread crust seems to be the Holy Grail, with attempts often spoiled by the ultimate "intermittent"!
If you have leftovers, store them for one day at room temp; they'll be less stale at room temp than refrigerated. After the first day, refrigerate or freeze. (French and Italian breads made only of flour, salt, yeast, and water are particularly susceptible to staleness. French law controls the ingredients in French bread; I don't know about Italian law. If your bread is made of only those four things, you'd better eat the whole loaf in the first day! Hah! Yum!)
Speaking of freezing, I've had pretty good luck putting once-risen-and-formed loaves in the freezer (on a cookie sheet and then bagged individually in a zip-top bag); I haven't tried this with bread in loaf pans but don't see why it wouldn't work). I thaw/second rise and then bake. This doesn't produce a result as tasty or as comely as baking right after the second rise, but it's pretty good in a pinch. I can't remember if I've ever frozen bread dough after the knead but before the first rise, so I can't report to you on the quality of the resulting bread; it ought to work, though.
Or use the microwave (no foil!). Be careful with microwave reheating; it takes a whole less time than you think! You do not want to make a loaf of toast, as I did! (See the disasters file, linked earlier.)
Some breads are not successful in a breadmaker (or in certain kinds of breadmakers)! I once made sourdough bread in my breadmaker. Gory details in the disaster file.
Well! This has turned out to be a longer essay than I had planned! I hope it gives you a little more insight into the chemical mysteries of breadmaking and the hands-on basics of the process. Enjoy your baking!