29.4 Rye and other flours

Rye

Rye is a tough cereal grass grown for its grain, and people have eaten it for over 2,000 years. It was once a staple in Scandinavia and Eastern Europe, and it lost ground as world trade made wheat easier to get. It grows well in cold northern places, including the Canadian Prairies, Wisconsin and the Dakotas.

Rye is the one flour besides wheat that can make a yeast-raised bread without being blended with wheat flour. Its food value is about the same as wheat's, and its lysine, an amino acid, is in some cases better.

Milling rye

Rye is cleaned, tempered and milled much as wheat is. The difference is that its endosperm is soft and turns to flour much faster. It gives no semolina, so purifiers are rarely needed. The break roller separates the bran, and the flour is rolled and sifted further into grades.

• Chop: the miller's word for the coarse stock that comes off the break roller.
• Meal: like chop, made by grinding the whole rye kernel, at 100% extraction.
• Light rye flour: from the center of the kernel, low in protein and high in starch, much like white bread flour. It makes light rye breads.
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• Medium rye flour: a straight flour, meaning all of the kernel once bran and shorts are taken off. It is light gray, has 1% ash, and goes into many sourdough breads.
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• Dark rye flour: like first clear wheat flour, with 2% ash and 16% protein. It is used mostly for heavier rye breads.

The lighter rye flours are usually bleached, most often with chlorine. This only lightens the color; it does nothing for the gluten.

How much of the grain is kept

How much of the rye kernel goes into the flour affects how much dough a batch yields and the flavor of the bread. Two rye flours compare like this, by their dry matter:

The flour that keeps more of the grain has more ash, fiber and pentosans, and less starch. Pentosans are gummy carbohydrates that swell when wet. In the oven they help a rye loaf hang together and keep its shape. Rye flour has more of them than wheat flour, and they matter more to a good rye bread.

Why rye bakes differently

Some dark rye flours carry as much as 16% of gluten-forming protein, but all of it is gliadin. Rye has no glutenin, the protein that makes dough elastic. So a dough of rye flour alone cannot trap the gas the yeast gives off while it ferments, and the loaf comes out small and dense.

In rye, starch and pentosans count for more than gluten. Starch is what builds the loaf's structure, and how well it does that depends on the flour's age and acidity. Rye flour needs less aging than wheat flour, but it has both a "best after" and a "best before" date; about three weeks after milling is thought good.

• Too fresh: the starch sets (gelatinizes) fast, at a heat where amylase enzymes are still very active, so the bread may be sticky and very moist. see chapter 7: Starch gelatinization
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• Too old: the starch is slow to set, the enzymes are unable to work, and the loaf may crack and split. Some breakdown of starch is needed for the dough to swell.

Rye flour should hold 13 to 14% moisture; the drier it is, the better it keeps. Store it the way you store wheat flour.

In short, rye differs from wheat in these ways:

• It grinds to powder more easily, and it gives no semolina.
• Its gluten matters little to the dough, while its starch matters more than wheat's does.
• It has more pentosans, and they count for more in the bread.
• Its starch and pentosans let it bind more water than wheat flour.

Both grains are highly nutritious and have long been called the "staff of life". Modern North American mills even out differences between crops, so bakers get flour they can rely on, in many types made for different products and tastes.

Corn in the bakeshop

Corn is one of the most widely grown grains in the world. Besides breads and cereals, it gives many other products.

• starch
• sugars, corn syrup and dextrose among them
• plastics
• glues
• ethanol fuel
• spirits such as bourbon

Its formal name is maize. Some kinds are soft and sweet, for eating fresh; others are starchy and are dried for baking, animal feed and popcorn. Corn as a vegetable and as hominy and masa harina is covered with grains. see chapter 16: Corn

• Cornmeal feels sandy and is ground fine, medium or coarse, with most of the husk and germ removed. It is used in dishes of the American South such as cornbread, and adds texture to other breads and pastry.
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• Stone-ground cornmeal keeps some husk and germ, so its texture is close to whole wheat flour. It is more nutritious but spoils sooner. With no gluten, it behaves more like cake flour in baking.
• Blue cornmeal is light blue or violet, ground from whole blue corn kernels. It is closest to stone-ground cornmeal and tastes slightly sweet.
• Corn flour, in North America, is cornmeal ground very fine, with husk and germ removed, and feels soft and powdery. In the United Kingdom and Australia, though, "corn flour" means cornstarch.
• Cornstarch is the starch taken out of the maize kernel. It is a very fine powder that mixes easily into water, and it is used mainly to thicken. It needs heat to set and gives a clear, shiny result. see chapter 7: Thickeners and gelling agents compared
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Rice and oats

Rice is a staple for much of the world. It is not a crop grown in Canada. Rice flour is ground fine from rice with the husks removed. It is a little sandy, and with no gluten it gives crispness while staying tender, which is why many gluten-free breads are built on rice flour or blends that include it. In the pastry shop, short grain (pearl) rice also makes rice pudding and other desserts.

Oats feed animals and people, and in baking they go into breads, cookies and dessert toppings, where they add texture.

• Rolled oats, the kind bakers meet most, are de-husked whole kernels pressed through rollers.
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• Oat bran and oat flour come from grinding the kernels and separating the bran from the endosperm.
• Whole grain oat flour is the whole kernel ground with nothing taken out.
• Steel-cut oats are chopped kernels, used more in cooking and for breakfast cereals than in baking.

Other grains and pulses

Corn shows up most in quick breads and oats most in cookies, while rice flour is used more and more for customers who are sensitive to gluten. Whole grain eating and the cooking of many cultures have also brought in more flours from other grains and from pulses.

In Canada these flours are becoming easier to find. They come from grains like spelt, quinoa and kamut, from pulses such as lentils and chickpeas, and from crops such as buckwheat that dry to a grain-like form. As allergies and intolerances grow more common, bakeshops use them to make products without wheat for customers with special diets.