Sweat – Sweating is the gentle heating of vegetables in a little oil or butter, with frequent stirring to evaporate liquids and yield tender, sometimes translucent, pieces. As compared to sautéing, sweating is done over a much lower heat, sometimes with a bit of salt, and making sure that little or no browning takes place. You will practice this step routinely making soups, stews and sauces that begin with a classic mirepoix.