Why do some recipes for chicken stock start with cold water and others with boiling water? Does the temperature really matter?
To find out, we prepared a recipe for simple chicken stock both ways, adding 4 quarts of either cold tap water or boiling water to raw chicken pieces in two pots and then gently simmering both stocks for 3 hours.
Tasters noted that the cold-water-start sample was more transparent, while the stock made with boiling water was slightly cloudy. As for flavor, tasters couldn’t detect any significant differences. Our science editor explained that the higher initial temperature of the boiling water extracts more insoluble proteins from the meat and bones, making the stock appear cloudy as it cools back down to a simmer. (The other broth was simply brought to a gentle simmer and never reached a full boil.) These insoluble proteins, however, don’t contribute any taste.
In our book, that’s good news: With no need to boil water separately, there’s one less thing to worry about when making stock.