32Yeast bread

Most bread dough is built from four things: flour, water, salt and yeast. The skill lies in two processes that happen inside it. Gluten forms and gets stronger, and yeast ferments and makes gas. Every step of bread making is there to manage one or both of them.

A bread needs a grain starch, water and something to make it rise. Some breads leave out the rising agent altogether, such as tortillas and naan, and these are flat breads. Yeast bread is the risen kind, and in most of it the rising agent is baker's yeast.

32.1 Yeast and what it does

Yeast is a fungus made of one cell. It multiplies by budding, and in the right conditions it ferments. How it turns sugar into alcohol and gas is explained in the fermentation chapter. see chapter 26: Alcohol and gas

People have made risen bread for a very long time. The early Chaldeans, Egyptians, Greeks and Romans all let their doughs ferment, but the results were hard to predict and control. In the 19th century the French scientist Louis Pasteur studied the causes of disease and how to prevent it. That work laid the ground for the yeast that factories grow and sell today.

Kinds of yeast

Wild yeast floats in the air on specks of dust, and it lives in flour and on the skins of fruit. It forms spores more quickly than grown yeast, but it does not behave the same way twice, so it is no good for fermentation that must be controlled.

Compressed yeast, also called fresh yeast, comes from one chosen strain that tests have shown to be strong and steady. It is made in stages.

• It is grown in a sterile place, away from other yeasts, and fed on wort: a mix of cleaned molasses or malt, nitrogen-rich matter and mineral salts.
• When it is mature, machines spin it away from the used wort.
• It is chilled, filtered and pressed into blocks.
• The blocks are cut, wrapped and kept cold.

It is sold in 454 g (1 lb.) blocks, and in 20 kg (45 lb.) bags for large bakeries. It is mostly water, about 68% to 73%.

Active dry yeast comes from a different strain. It is grown the same way, then mixed with starch or another absorbent and dried, down to about 7% moisture. It was first made after the Second World War, for the armed forces, home cooks, and places with no fresh yeast.

• It is dry, but it is still alive. For best results keep it closed and refrigerated below 7°C (45°F). If there is no refrigerator, keep it unopened somewhere cool and dry, and only for a limited time. Let it come up to room temperature slowly before you use it.
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• Soak it before use for about 15 minutes, in water weighing at least four times as much as the yeast, at 42°C to 44°C (108°F to 112°F). Never let that water drop below 30°C (86°F), and never use the yeast until it has fully dissolved.
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• To stand in for 2.2 lb. (1 kg) of compressed yeast, use about 550 g (20 oz.) of active dry. For every kilogram of dry yeast, add another kilogram of water to the mix. Bakers now seldom use it, because instant yeast has taken its place.

Instant dry yeast does not need soaking first. You can stir it into the flour before the water goes in, or add it once the other ingredients have mixed for one minute.

• It can be dissolved if you wish. Some makers say to use five times its weight of water, between 32°C and 38°C (that is, 90°F and 100°F).
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• To replace compressed yeast, most formulas use one part instant to three parts compressed, and some use one to four. In place of each kilogram (2.2 lb.) of compressed, use about 250 g to 300 g (9 to 11 oz.) of instant in bread dough, or about 400 g (14 oz.) in a rich Danish dough. Add a little extra water too, roughly the weight of compressed yeast you left out minus the weight of instant you used. The packet gives exact instructions.
• It holds about 5% moisture and comes in vacuum pouches. Sealed, it keeps about a year at room temperature with no clear loss of gassing power. Once opened it becomes a grainy powder; refrigerate it and use it by the best-before date. It takes up less space and keeps longer than compressed yeast.

Cream yeast is a soft, runny yeast. Only large commercial bakeries use it, pumping it straight into the dough.

Yeast food is not a yeast. It is a blend of mineral salts, such as a calcium or ammonium salt with potassium iodate, used to condition bread dough and make it ferment faster. It tightens the gluten, which helps most where the water is soft, and it improves how the bread looks and tastes. Retail bakers rarely use it.

What yeast does in dough

Yeast has two jobs in a dough. It turns sugar into carbon dioxide gas, which lifts the dough and fills it with air. It also softens and conditions the gluten, so the dough can stretch evenly as the gas builds up and still hold it in. A baked product made with yeast has more volume and better flavor, texture, grain and color.

Flour, water and yeast together hold everything fermentation needs: soluble protein for building new yeast cells, and sugar to feed them. Enzymes in the yeast first change complex sugar into invert sugar, which the cells take in and turn into gas and alcohol. Meanwhile, other enzymes from the yeast and the flour break soluble starch down into malt sugar, and then into sugar the yeast can ferment. That keeps the gas coming.

Handling and storing yeast

Good compressed yeast is moist and firm. It breaks cleanly without crumbling and smells fresh and fruity. As it ages it turns into a sticky mass that smells of cheese. It weakens slowly even in the refrigerator, and you cannot always tell by looking whether it is still strong enough. How well it works depends on its age and on the temperature and humidity it was kept in.

• The best storage temperature is −1°C (30°F). Yeast does not freeze at that temperature and keeps its full strength for up to two months.
• Use the oldest yeast first.
• Leave space between packs on the refrigerator shelf. Yeast is alive and keeps breathing, slowly in the cold and quickly in a warm shop, so packed tightly it can overheat. With no food, breathing yeast starves and dies.
• Yeast that has been frozen and thawed must be used at once. Freezing weakens it, and it cannot be frozen again with success.
• Take out only what you need, and never leave compressed yeast on the bench for more than a few minutes; at room temperature it spoils fast. Some bakeries keep a small cooler on the bench to save trips to the refrigerator.
• Keep it wrapped at all times. Air turns the edges and corners brown, a fault called air-burn.

Getting yeast into the dough

Many bakers crumble compressed yeast straight into the dough. The older way is to dissolve it first in lukewarm water. That water must never go above 50°C (122°F), because heat kills yeast cells. As a rule, keep salt from touching the yeast directly, because salt draws water out of it.

Temperature sets the pace of the yeast.

32.2 Yeast doughs: mix, knead, proof

Lean, rich and laminated doughs

Yeast doughs fall into three families, set by how much fat and sugar they carry.

• Lean doughs are low in fat and sugar. The leanest are the hard, crusty breads: French bread, hard rolls and pizza dough. White and whole wheat breads may hold a little fat and sugar, which gives them a softer crumb and crust. Grain breads use other flours and grains, such as rye, oat, flax seed and sprouted grains, and may carry additions that bring sourness or sweetness.
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• Rich doughs hold a lot of fat and sugar, and eggs as well, which makes them softer and richer. They can be sweet or not, depending on the sugar and the toppings. Brioche, coffee cake and dinner rolls are rich doughs.
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• Laminated doughs have fat rolled into them and are folded again and again to build layers, which bake up flaky and buttery. They contain some sugar, but most of their sweetness comes from fillings and toppings. Croissants and Danish are the two main kinds.
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The twelve steps

Bread is made in a fixed order of steps. Each one builds on the one before, and none can be hurried or moved.

• Scaling the ingredients
• Mixing
• Bulk fermentation
• Folding
• Dividing
• Preshaping, or rounding
• Bench proofing
• Makeup and panning
• Proofing
• Baking
• Cooling
• Storing

Scaling and mixing

Bakery formulas are exact, so every ingredient is weighed. Liquids can be measured by volume, but in large batches it is more accurate to weigh them too. Take special care with spices and with salt, which plays a large part in how the yeast ferments. Weighing and scaling are covered with measuring. see chapter 5: Scaling and converting a recipe

Mixing spreads the ingredients evenly, forms a smooth dough, and starts the gluten.

• The flour, yeast and other dry ingredients go in the bowl first and are stirred with the dough hook to spread the yeast through.
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• Then the liquid goes in, and gluten begins to form.
• As the dough comes together it pulls away from the side of the bowl, a stage bakers call take up.
• The hook stretches and folds the dough the way hands do in kneading, which lines up the gluten strands so the dough can rise.
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The mixer and its hook are described with the bakeshop tools. see chapter 3: Mixers

A small loaf can be made by hand.

• Beat the dough with a spoon until the batter drops off in sheets.
• Stiffen it with flour until it is soft and easy to handle.
• Rest it for 5 minutes on a floured surface.
• Knead it for 10 to 15 minutes, until its surface turns smooth and shows small blisters.
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Heat sets the gluten in the oven. see chapter 7: Flour

Bulk fermentation and folding

Bulk fermentation is the first rise, with the dough still in one piece. The yeast feeds on sugars and starches and gives off carbon dioxide and alcohol, and the gluten acts as a net that traps the gas, so the dough grows.

• Mixing time and fermentation time balance each other: a long mix needs a shorter ferment, and a short mix needs a longer one.
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• Getting the time wrong spoils the bread. Dough fermented too long turns hard and tough; dough fermented too briefly lacks volume.
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• Use a container big enough for the dough to expand. Check the dough temperature; the usual target is 80°F. Cover the dough so air cannot dry the top into a skin, which would ruin the texture. Some doughs are oiled instead.
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• For the small hand-made loaf, the dough goes into a greased bowl and is turned once so the top is greased. It is covered with a clean damp towel and left somewhere warm, 26°C to 32°C (79°F to 90°F), until it has doubled: 45 to 60 minutes, or 30 minutes with fast-acting yeast.
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Folding, or punching down, is done during bulk fermentation. As the dough expands, the baker presses out the gas and folds the dough over. Too much carbon dioxide is one of the things that slows the yeast, so releasing it lets fermentation carry on. Folding also realigns the gluten, much as kneading does, and keeps the dough temperature even. How many folds a dough gets depends on how it was mixed.

Dividing, rounding and resting

Dividing cuts the dough into pieces of the right weight.

• Cut a piece close to the weight you need with a bench scraper.
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• Put it on the scale.
• Add or trim until it is right.
• Check the weight again.

Bread loses about 10% to 13% of its weight to evaporation as it bakes. To make up for it, add about 1½ to 2 oz. of dough for every pound of baked bread you want. A dough divider press cuts a lump of dough into 36 equal pieces, and the same loss must be allowed for.

Preshaping, usually into a ball, gives each piece a smooth surface and pulls the gluten tight so fermentation can go on. It is also your chance to feel the dough. Give a slack, loose dough a tighter shape, and a tough, stiff dough a looser one. Bring the preshape as close as you can to the final shape.

Bench proofing lets the rounded pieces rest on the work surface for 10 to 20 minutes, under plastic wrap laid on loosely. The gluten relaxes, ready for shaping, and the dough keeps fermenting and rising.

Makeup and panning

Makeup is shaping the dough into its finished form: a round, an oblong, a baguette, a dinner roll. How you handle it decides the crumb, the inside texture of the bread. For a tight crumb, press out every gas bubble. For an open crumb, work gently and keep the air pockets, because every bubble left in the dough becomes a hole in the bread.

To shape a pan loaf:

• Punch the dough down and put it on an unfloured board, cloth or counter.
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• Flatten it with your fingers and work out any big bubbles.
• Press it into a rectangle about 5 by 10 inches.
• Roll it up toward you from a short end, and pinch the seam to seal it.
• Seal each end with the edge of your hand, pressing it into a thin strip about ½ inch wide.
• Fold the ends under and set the loaf, seam down, in a greased 6 by 3¼ inch pan.
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Proofing

Proofing is the last rise before baking. It happens either in a proof box or somewhere warm and dry. In a proof box, set the temperature and humidity the formula calls for. Breads high in fat usually proof cooler, so the butter does not melt and run out of the dough. The proof box is described with the bakeshop tools. see chapter 3: Proofing

• Proofing takes from 30 minutes to 2 hours, depending on the dough.
• The dough is ready when it has doubled and springs back lightly when you touch it.
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• Do not knock the gas out of a proofed dough. If you do, it will not rise in the oven. Proofing ends the fermenting and rising stages.
• The small hand-made loaf proofs covered in a warm place, 29°C (85°F), until nearly doubled: 25 to 30 minutes, or 15 with fast-acting yeast.

Baking

Set the oven for the bread you are baking. A convection oven and a deck oven bake differently.

• Washes. Before it goes in, bread may be brushed with water, egg wash, heavy cream or another wash. Each one changes the crust and how the loaf looks.
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• Steam. Ovens that can inject steam help the crust form while letting the loaf expand fast without tearing. Steam also spreads the heat and helps oven spring.
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• Oven spring is the last rise a bread takes once it starts to bake. After it, the structure sets as the dough heats up, and the yeast dies at 140°F.
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• Scoring means cutting slits in the top of the loaf so it does not split as it rises in the oven. Use a sharp knife or a lame, a curved razor tool.
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• The small hand-made loaf bakes at 425°F for 25 minutes and comes out of the pan straight away to cool.

A brown crust, like the outside of a roast, gets its color and much of its flavor from the Maillard reaction. see chapter 8: What roasting is

Cooling and storing

Take the bread out when it reaches the right internal temperature for its type, and set it on a cooling rack. As it cools, extra moisture escapes, and so does the alcohol the yeast made. Most breads cool on their pan, but bread baked in a loaf pan can be turned out and laid on its side, so steam does not collect underneath and make the bottom crust soggy.

Let bread cool all the way before you wrap it.

• Wrapping warm bread traps moisture and makes it wet and soggy.
• Keep it in moisture-proof bags, or wrapped tightly in plastic in its pan, to slow staling.
• Bagged bread keeps at room temperature if it will be eaten within a few hours or days. Freeze it for longer.
• The refrigerator makes bread go stale faster, and so does leaving it unwrapped on the rack.
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• Do not wrap hard-crusted bread; wrapping changes its crust.

A standard loaf

A good white loaf can be judged on three counts.

32.3 Salt and fermentation in dough

Salt's kinds and what it does to food in general are covered earlier. see chapter 20: What salt does in food In a yeast dough it has particular jobs and particular rules.

How much salt

A dough usually takes about 1.75% to 2.25% salt, measured against the weight of the flour. For 1,000 g of flour, that is 17.5 g to 22.5 g. Some authorities work from the water instead, at about 30 g of salt per liter (1 oz. per quart).

In hot summer weather, many bakers add a little more salt than in winter, to guard the dough against unwanted changes while it ferments.

Keep salt and yeast apart

Salt and gluten

Salts strengthen the gluten network. That goes for table salt and for the calcium and magnesium salts in hard water. In sponge doughs and liquid fermentation systems, a little salt in the first stage firms up the gluten. Fats and emulsifiers work the other way: they coat the proteins.

Where the yeast's sugar comes from

The yeast in most bread is Saccharomyces cerevisiae, baker's yeast. It eats the sugars in the dough and makes carbon dioxide and ethanol, which raise the dough both while it ferments and when it first goes into the oven. The chemistry of that change is in the fermentation chapter. see chapter 26: Alcohol and gas

Most of the sugar comes from the starch in the flour, which is made of two large molecules, amylose and amylopectin. Yeast cannot use starch as it is; it must first be broken down into simple sugars. Once flour, yeast and water are mixed, enzymes from the wheat and from the yeast start this work, and they keep at it into the baking.

• Wheat flour has two kinds of amylase, enzymes that split starch. One cuts the starch chain at random places into shorter pieces. The other snips off maltose, a double sugar, from the end of the chain.
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• Yeast brings its own enzymes. Invertase splits several small sugars, and maltase splits maltose into two simple sugars.
• Flour improvers sometimes carry extra amylase into the dough.
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How gluten forms

Protein makes up about 10% to 15% of flour. Two groups matter most: the glutenins and the gliadins. When water is added, the glutenins take it up, swell, and become stretchy and flexible.

Before kneading, these two proteins stay separate. As the dough is mixed and kneaded, enzymes from the wheat cut the glutenin into smaller pieces, and glutenin and gliadin start to link to each other. The result is a web of protein called gluten. Starch granules get caught in it, and kneading works air in.

Bread dough has to be stretchy enough to relax when it rests, and to swell and hold gas when it rises, while still keeping its shape. Different doughs want different amounts of gluten.

• Bread needs a web strong enough to trap the gas, yet loose enough to let it expand.
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• Pizza dough needs very strong gluten, so it can be pulled thin without tearing.
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• Cookies are usually crumbly and hardly rise.

In the oven the yeast goes on fermenting for a while, until the heat kills it.

The crust: browning

When sugars and amino compounds are heated together, a chain of browning reactions called the Maillard reactions begins. No enzymes are involved. They make many flavors, among them malty, toasted, bready and nutty ones. Some of the families of aroma compounds they build are these:

32.4 Rolls

Rolls are made from the same kind of soft, enriched dough, then shaped in many ways. The basic roll dough holds eight ingredients.

• yeast
• warm water
• scalded milk
• shortening
• sugar
• salt
• egg
• all-purpose flour

Making the dough

• Soak the yeast in warm water, 46°C.
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• Mix the scalded milk with the shortening, sugar and salt. Beat in ½ cup of the flour, and let it cool to lukewarm if needed.
• Beat in the yeast and the egg.
• Stir in only as much flour as it takes to make a soft dough. Let it rest 5 minutes.
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• Knead for about 10 minutes on a floured board, until the dough is smooth and elastic.
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• Put it in a greased bowl, turn it so the top is greased too, and cover with a damp cloth. Let it rise somewhere warm (26°C to 32°C) for 30 minutes.
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• Punch it down and shape the rolls. Set them on a baking sheet and let them rise somewhere warm until nearly doubled.
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• Plain rolls need 10 to 12 minutes at 425°F, until golden brown. Bake sweet rolls at 375°F. Move the baked rolls from the pan to a rack to cool.

To knead by hand:

• Push the dough away from you with the heels of both hands so it stretches.
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• Fold it in half.
• Give it a quarter turn.
• Repeat.

Kneading takes 5 to 15 minutes, depending on the dough. It stretches the gluten so the dough can hold the gas a leavener makes, and so it can rise.

Scalding the milk means heating it to 180°F before it goes into the dough. Without it, the dough turns out sticky and slack, and the bread is coarse with little volume.

The first-risen dough can go into the refrigerator for up to 72 hours, punched down as needed. Let it stand at least 30 minutes at room temperature before shaping. Refrigerated food is kept at 4°C (39°F) or colder.

Fast-acting yeast, also called bread machine yeast, uses more active strains. It may also carry enzymes and other additives, and it cuts rising and proofing times by about half.

Other roll doughs

• Potato rolls add mashed potato, made from fresh or instant, and more sugar. Plain ones bake at 425°F for 10 to 12 minutes and sweet ones at 375°F for about 12 to 14 minutes.
• Bran rolls use unprocessed wheat bran with boiling water poured over it, then stirred together with the shortening, sugar and salt.
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• Whole wheat bread or rolls add the flour in turns, white then whole wheat, so the two end up in roughly equal amounts. A loaf goes in a greased 6 by 3¼ inch pan and bakes at 425°F for about 25 minutes.

Shaping rolls

Handle the dough with care and shape it without tearing. Bake on a sheet sprayed with nonstick spray. After shaping, every roll is covered and left to rise until doubled before it bakes. Many shapes start from the same strips: roll out a rectangle of dough ½ inch thick and about 9 inches long, cut it into strips 9 by ½ inches, and roll each strip under your hands to round the edges.

Braids, coffee cakes and sweet rolls

The same dough makes larger breads and sweet rolls.

• Braided bread. Divide the dough in three, roll strands about 10 inches long, and plait them. Bake 15 minutes at 375°F, add a topping, such as caraway seeds with Cheddar or Swiss cheese with paprika, and bake 15 minutes more.
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• Braided pineapple coffeecake. Spread a pineapple, toasted coconut, brown sugar and cinnamon filling down the middle third of an 8 by 12 inch piece of dough. Snip the long sides into strips at 1-inch intervals and fold them over the filling in turn, in a herringbone pattern. Brush with egg white, scatter almonds, and bake at 375°F for 20 to 25 minutes.
• Rolled and sliced rolls. For cinnamon rolls, butterscotch rolls and orange swirls, brush a rectangle of dough with melted butter, scatter the filling, roll it up from the long side like a jelly roll, seal the seam, and slice. The slices go cut side down into a pan or muffin cups.
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• Butterscotch rolls sit on a brown sugar, butter and corn syrup topping heated in the pan first. A minute after baking, turn the pan upside down onto a plate and leave it about 5 minutes so the topping runs down over the rolls.
• Lemon-cinnamon twists are folded in half lengthwise, cut into 1-inch strips, and twisted by turning the two ends opposite ways. They bake at 375°F for 10 to 12 minutes.
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• Cream cheese pinwheels are 3-inch squares with a spoonful of sweetened cream cheese in the middle. Cut in from each corner toward the center, fold every other point in, and pinch them together. They bake at 350°F for 15 to 20 minutes.
• Swedish tea ring is a rolled log of dough with butter, brown sugar, cinnamon and raisins, bent into a ring. Snip it at 1-inch intervals, most of the way through, and turn each piece on its side. It bakes at 375°F for about 25 minutes and is iced while hot.

Pastries filled with meat, cheese or cream are among the potentially hazardous foods, which need temperature control. Potentially hazardous foods and the danger zone are explained in the food safety chapter. see chapter 2: Potentially hazardous foods

A standard roll

Good yeast rolls meet a standard on several counts.

• Size: all even and moderate.
• Outside: light golden brown.
• Inside: creamy and light.
• Grain: fairly fine and even.
• Crumb: springs back when pressed.
• Flavor: tender, mild and slightly nutty, lifted by whatever else went into the dough.