Food - Drink
Why Martha Stewart Says You Should Never Boil Stock
By MELISSA CORBIN
According to Martha Stewart, the actual process of making stock, no matter the protein source, takes a fair amount of time—which is approximately eight hours. When Stewart makes her brown beef stock, she ensures that her water, once added, is for a slow simmer and warns against boiling the precious liquid at high temperatures.
High temperatures yield a cloudy stock since scientifically, according to Adolph Fick’s law, "the rate of diffusion of a substance across unit area (such as a surface or membrane) is proportional to the concentration gradient." As the law applies to a quality stock, factors such as surface area, pressure, flavor concentration, and temperature play important roles.
With temperature, the higher the temperature, the faster flavor molecules will move, which will emulsify the bone fat quickly into the agitated stock, creating cloudy conditions. However, impurities and ingredient particles won't affect the taste of your stock unless you're making consommé, and you can always strain them out after.