A modernist sauce does not rely on reduction alone to create body and thicken the sauce, but rather incorporates natural hydrocolloid thickeners that can have much the same mouthfeel as butter or cream. To give body to a sauce with xanthan gum, blend in about 0.2 gram per ¾ cup (190 milliliters) liquid. Xanthan gum is convenient because it disperses in both hot and cold water and thickens immediately. But there are some who find the mouthfeel of xanthan-thickened sauces to be “slippery” or “slick.” To avoid this, use half the amount of xanthan gum (0.1 gram per ¾ cup/190 milliliters liquid) and blend in 0.5 gram propylene glycol alginate per ¾ cup (190 milliliters). If you’re creating an emulsion and wish to stabilize it, add 1.5% lecithin and perhaps 2% to 4% Glice (mono- and diglycerides) to the butter.