INGREDIENTS

Whereas a "conventional" loaf of bread is usually made with only one type of flour, such as wheat or rye, gluten-free baking needs a blend of flours to produce the best results.

Here's a list of the ingredients you might find in my and others' gluten-free recipes, with a description of each one's unique characteristics and uses.

Flours

Arrowroot: A very light, fine starch that is good for thickening sauces and custards, and excellent in pastry dough.

Buckwheat: It's not remotely related to wheat; in fact, it's not even truly a cereal grain. Nonetheless, it lends a distinctly grainlike, rustic flavour to baked goods. It can even be delicate: it serves as the main flour in French savoury crepes.

Buckwheat, malted: While "malt" usually means something off-limits for gluten-intolerant people, it actually refers to a process rather than any specific grain; essentially the grains are sprouted and then roasted for a nutty, sweet flavour. Instructions on malting buckwheat are given in this post.

Chestnut: In contrast to other "nut" flours, this flour is very low in fat, so it performs more like a lightweight flour or starch. It is very finely-textured, starchy, and slightly sweet.

Garbanzo Bean (Chickpea): This flour has an important place in hearty yeast bread, dense sweet breads, and other things with a close crumb and complex flavour. It adds protein and fibre to the flour blend, too, which balance out the starchy taste that some GF breads have. Some people consider it bitter; in small quantities the taste does not come through, and in larger amounts I think it is all a matter of using it for the right things. For instance, there is a wonderful traditional flatbread, from the Provence region of France, using this flour exclusively.

Millet: Slightly sweet with a delicate crumb, this flour has been used for flatbread in India for centuries. It's best in small amounts for yeast breads - more makes the bread crumbly - but it can be used liberally in muffins and cakes. It is useful when converting wheat-based recipes which call for semolina flour, such as fresh pasta and certain Italian breads. Millet absorbs more water than the same quantity of many other grains like brown rice.

Oat Flour: Most people with celiac disease can eat oats, though some cannot tolerate them, so make sure it is OK for you to consume oats before using them. It provides good texture in yeast breads, and is a traditional part of many soda breads, quick breads, and cookies.

Potato Starch: Not to be confused with potato flour. Potato starch is a good neutral-tasting ingredient to fill out baked things, and can help make bread softer. Potato starch absorbs more water than the same mass of some other starches, so be sure to adjust your recipe accordingly. When you use it in bread, be sure to let the bread cool sufficiently before cutting it. Otherwise, the loaf will fall and become gummy.

Rice, white: This is one of the most widely known flours in wheat-free baking. It can be used in just about anything, though if large quantities are used, it can make baked goods too starchy and crumbly.

Rice, brown: This flour is made from the whole rice grain, which means it contains all the nutrients and fibre you might expect from an unrefined food. Compared to other whole grains it is also fairly light-coloured and mild, so it can be used in most baking - in fact, I usually prefer it to white rice. Large amounts of this flour can make your bread taste distinctly like rice, though, so it's best used in combination with other grains.

Rice, sweet (also known as mochiko): It's made from sticky rice, and is traditionally used in Japan to make very gummy little rice cakes called mochi. You might see it in recipes for cake, muffins, or pancakes. I find it useful for thickening sauces and soups as well.

Sorghum: This flour is slightly sweet, and gives drier baked goods, such as cookies, the "grainy" taste and texture that is sometimes missing. For some reason it can make breads taste like cornbread, though.

Tapioca Starch (also called tapioca flour): This is common in most gluten-free baked goods, and it is the primary starch I use. It is lighter than potato starch. 

Tapioca Starch, modified: This is marketed under the brand name Expandex. You will see it in most of my older recipes, which also contain gums and egg - in some of these applications, it improves the rise and texture. In eggless yeast breads, and in things which do not contain gums, it does not seem to make a difference. I no longer use it.

Teff: I've only tried the dark brown variety, though this tiny grain can also be ivory. The flour is high in iron and fibre. It also lends a slight taste of something rich and sweet, like molasses or carob, to your baking. The grains are so small that you can even use them whole, similar to bran.

Other Ingredients

Egg Replacer: Though it is often used to make recipes without eggs, it also may show up in addition to eggs in some gluten-free recipes. This is because it helps with binding and gives a little extra leavening.

Guar Gum: A binding agent derived from a plant.

Pectin: Pectin is a very good binding agent - I prefer it to gums. It is most frequently used in making jam - it is what helps it gel. Most brands of pectin contain extra ingredients such as cornstarch, dextrose, and citric acid. For pure pectin, see below.

Pomona's Pure Citrus Pectin: Unlike other brands of pectin, there are no fillers or extra ingredients added. (For this reason, if you are substituting a starch-containing pectin, use about twice as much as the amount of Pomona's specified in my recipe.) This is a special variety of natural pectin, and I find it to be a more effective binder than other brands. Pomona's comes in a box with two packets: the large packet is pure pectin, the small packet contains calcium phosphate (a naturally occurring compound, which interacts with the pectin to help it bind). I recommend combining the contents of both packets in a small jar, and just measure from the jar whenever a recipe calls for Pomona's.

Psyllium Husks: The husks of small seeds, which I use as a binding agent. They interact with water much like flax seed powder, but unlike flax, they are soft and barely noticeable in the baked food.

Xanthan Gum: A binding agent made by microorganisms. It can cause a gluey texture.