Guar gum is a food thickening agent, almost eight times as powerful as cornstarch for thickening applications. Guar gum does not require heat to thicken liquids and prevents ice crystals from forming in foods. Guar gum is produced from a bean called the cluster bean or guar bean, grown primarily in Pakistan and India. Guar gum is used in much the same way as xanthan gum and both agents can normally substitute for the other. Guar gum is usually packaged as a loose, light-colored powder with a coarse to fine texture.
Adding the Right Amount for Thickening
Use guar gum in place of flour or cornstarch in recipes to act as a thickening agent. When using guar gum in place of flour, use a sixteenth of what is called for in the recipe.
For example, if your recipe calls for 2 tablespoons of flour, use 3/8 teaspoon of guar gum. If the recipe calls for 1/4 cup of flour, use 3/4 teaspoon of guar gum. Measure exactly, as even small changes in the amount of guar gum can result in a changed consistency.
If you are replacing cornstarch in a recipe for thickening, use an eighth of what is called for. If the recipe calls for 2 tablespoons of cornstarch, use 3/4 teaspoon of guar gum. If the recipe calls for 1/4 cup, use a 1 1/2 teaspoons of guar gum.
Techniques for Use
Since guar gum does not require heat for thickening, it is useful for thickening room temperature or cold dressings and sauces. Guar gum is relatively tasteless, especially since so little is used compared to the bulk of the recipe. Add the guar gum by 1/8- to 1/4-teaspoon increments and stir or shake well. Adding too much will give the food a gummy texture.
Guar has a tendency to clump. To combat that, sprinkle the guar gum into the food evenly. Some people like to use clean spice shakers. Add the amount you want into the shaker and sprinkle it in, continuously stirring.
Applications Beyond Thickening
In gluten-free baking, guar gum can be added as a binder to replace the protein, gluten. Baking products using regular flour rely on the gluten in the flour to help with the texture and structure. The amount of guar gum that you should use in each recipes varies, but generally speaking, for every cup of gluten-free flour in the recipe, use 1/2 teaspoon of guar gum for cakes, 1 teaspoon for breads and pizza crusts and 1 1/2 teaspoon for cookies.
References and ResourcesListing of Guar Gum including History and Chemistry
Using Guar and Xanthan Gum in Gluten-Free Baking
Chemical Formula, Description and Uses of Guar Gum