It’s hard to know where to start with an ingredient as incredibly versatile as xanthan gum. Yes, it’s a thickener, but really it’s much, much more than that. Add water and it becomes an elastic goo that works as a thickener, an emulsifier, a gluten replacer for gluten-free breads, a foam reinforcer, a fat replacer, a moisture enhancer, the list goes on. Notice I said “add water” and not “heat” for xanthan gum will thicken a liquid of any temperature, hot or cold. It doesn’t clump, so it can simply be whisked into a cold salad dressing or a hot sauce. A few seconds later — presto chango — you have an increase in viscosity.
Just how much of an increase of course depends on how much xanthan gum you add. And it’s here that some cooks get into trouble as too much xanthan gum creates not a sauce but a mucous. So it’s best to tread carefully. Happily xanthan gum allows you to do that, adding a little more and maybe just a touch more until you achieve the consistency you want. One thing xanthan gum won’t do is create a JELL-O like gel. Actually I should amend that: eventually xanthan gum will do that, but the result will be so gluey and dense you wouldn’t want to eat it.
Using xanthan gum is quite easy. On average it’s about six times as powerful as any pure starch thickener when it comes to thickening liquids. Like starch thickeners it creates a smooth, shiny and transparent “gel” but where you might use three teaspoons of cornstarch for a given recipe, you’d only need half a teaspoon or less of xanthan gum. It creates gels of medium clarity that are remarkable acid-resistant. Used in combination with guar gum it forms gels that are both stringer and more elastic.
In breads — and this is where xanthan gum is especially cool — you add one teaspoon of xanthan gum to a cup of any gluten-free flour to approximate a weak, low-gluten flour, and up to two teaspoons per cup if you want something more like a strong, high-gluten flour. Quick breads require less, about 3/4 teaspoon per cup of gluten-free flour, and 1/2 teaspoon for cakes and cookies.
There’s so much to be said about xanthan gum, but I’ll stop here for now. I may well supplement this post over time as I think of more stuff to add!