Xanthan gum, psyllium husk powder, and guar gum are frequently called for in gluten-free recipes and serve the same general purpose as thickeners and binding agents. You can use one or the other or, sometimes for the best results, use them together.
In recipes containing wheat (also rye or barley) the protein (gluten) in the flour serves the same purpose that guar gum, psyllium husk powder, and xanthan gum do in gluten-free baking. Gluten protein is what traditional recipes rely on to thicken dough and batters, trapping air bubbles to make your baked goods light and fluffy. Xanthan gum tends to help starches combine to trap air, while guar gum helps keep large particles suspended in the mix. Psyllium husk powder is used to retain moisture and help breads from becoming too crumbly.
Guar gum is good for cold foods such as ice cream or pastry fillings, while xanthan gum is better for baked goods including yeast breads. I’ve used psyllium husk powder for both purposes. Foods with a high acid content (such as lemon juice) can cause guar gum to lose its thickening abilities. For recipes involving citrus you’ll want to use xanthan gum or increase the amount of guar gum used.
There are no set rules on which one you use; you’ll have to experiment yourself to see what works best in your recipes. Most packages of xanthan gum, psyllium husk powder, and guar gum have recommendations for how much to use with different types of recipes.
Helpful Measurements:
Xanthan Gum or Psyllium Husk Powder for gluten-free baking
Cookies………………………………¼ teaspoon per cup of flour
Cakes and Pancakes………………½ teaspoon per cup of flour
Muffins and Quick Breads………¾ teaspoon per cup of flour
Breads………………………………1 to 1-½ tsp. per cup of flour
Guar Gum for gluten-free baking
Cookies………………………………¼ to ½ tsp. per cup of flour
Cakes and Pancakes………………¾ teaspoon per cup of flour
Muffins and Quick Breads…………1 teaspoon per cup of flour
Breads………………………………1-½ to 2 tsp. per cup of flour
