As you know, the biggest problem with gluten-free baking is finding a suitable substitute for wheat gluten that mimics the springy, stretchy texture of dough made from wheat flour. Gluten is also the factor that helps cakes and bread dough retain the carbon dioxide bubbles that form inside the mixture while cooking, making the cake or bread light and pleasant to eat.
Xanthan gum and guar gum are two ingredients that can be used to substitute for gluten in baking to render the dough springy and light. Due to their ability to attract water and thicken and bind gluten-free ingredients, gums are termed "hydrocolloidals".
Xanthan gum is a polysaccharide, which is the name given to a string of sugars and carbohydrates. Often used as a binding ingredient in commercially produced salad dressings, gravies and sauces, xanthan gum also helps oil and vinegar to mix together and prevents ice crystals from forming in frozen goods such as ice cream.
Xanthan gum is derived from the bacterium Xanthomonas campestris. To obtain xanthan gum, the Xanthomonas campestris bacteria are applied to a sugar - usually corn sugar - and left to ferment. The resulting product can best be described as a "slime" that is dried and ground, and later added to a liquid medium to produce xanthan gum suitable for cooking.
In baking xanthan gum helps ingredients to hold together, producing baked goods with the right texture and elasticity. Xanthan gum is expensive, but very little needs to be used to obtain the right texture.
When adding xanthan gum to recipes, care should be taken not to over-mix the ingredients afterwards, as too much mixing can cause the cake or cookies to become rubbery and tough. Just a few stirs are necessary. Try adding 1/2 teaspoon of xanthan gum per cup of flour for cakes, 3/4 teaspoon per cup of flour for breads and 1/4 - 1/2 teaspoon per cup of flour for cookies.
Unfortunately, some celiacs or people sensitive to corn cannot tolerate xanthan gum, so guar gum can be used as a substitute.
Guar gum is made from the ground endosperm of the guar bean. Once the seeds are dehusked and ground, they are sieved to obtain the guar gum, which is a whitish powder. Guar gum is also a hydrocolloid and is a polysaccharide composed of sugars called mannose and galactose.
Guar gum has about 8 times the thickening ability of cornstarch, so it can be used in place of flour to thicken sauces. It has similar properties to xanthan gum, as it can also be used as an emulsifier to help oil and vinegar combine, and as a stabilizer to prevent particles from settling in a liquid. Try using a mixture of 1 cup of wheat-free flour and 1 teaspoon of guar gum for every cup of wheat flour in recipes.
Although, using a combination of both xanthan gum and guar gum can produce the best results. If the recipe states that you should use 1 tablespoon of xanthan gum, try using one and a half teaspoons of xanthan gum and one and a half teaspoons of guar gum.
So, how do you add these gums to the ingredients? Personally, I found that adding gums to liquids makes them clump. To avoid clumping when adding gums, I blend them with one of the dry ingredients such as the flour or sugar. This way the ingredients bind together in a smoother way with fewer lumps.
After some experimentation with both guar gum and xanthan gum in breads, I found that using guar gum for loaves made the bread very crumbly and not at all “bread-like”. On the other hand, using xanthan gum gives the bread a spongier texture and much more like bread made from wheat.
In the end, experimentation is the order of the day. Experimenting with different blends of flours with gums will ultimately give you the combination that works for you.
Need some help converting a regular recipe into a gluten-free version? Download our Flour Conversion Chart