I made some Tabasco hot sauce but what I find is that the chilies and vinegar separates in the bottle when standing on the rack for a long time. To try to prevent this my thought was to use xanthan gum, is this the right approach?
I was recently asked this question about what the best method of stabilizing a sauce is. Sauces, emulsions, and other mixtures are basically two or more types of ingredients that don't fully mix but are held in suspension. So an emulsion is typically a mixture of oil and vinegar and a hot sauce is a mixture of chile particles and vinegar. The problem with these mixtures is that when they sit, the two ingredients separate from each other. This is why salad dressing often needs to be shaken up before using it.
There are many ways of stabilizing an emulsion or a particle solution, but the easiest is to slightly thicken the mixture with a thickening agent. Large, processed food companies use a combination of different thickeners based on the ingredients in the emulsion, but for home cooks xanthan gum is a great place to start.
The addition of about 0.05% to 0.1% xanthan gum, by weight, is enough to start holding the particles in suspension without changing the consistency or thickness of the sauce very much. The separation will probably still occur, but it will take much longer for it to happen and the ingredients will move back into each other more quickly with a shake or two. If the mixture is oil and vinegar the addition of soy lecithin can also help keep it from separating.
View more recipes showcasing how to thicken with xanthan gum.
You can experiment with lots of other types of thickeners, but it's a fine line between keeping the particles in suspension while still not changing the texture or consistency of the sauce. That's why I usually turn to a low level of xanthan gum, I might still have to re-mix it occasionally but the sauce still has the consistency I originally wanted.