Simmer vs. Boil: How to Tell the Difference
A boil has big, rolling bubbles; a simmer has small bubbles that break gently. Most sauces, soups and stews want a simmer.
Boiling and simmering are only a few degrees apart, but they do very different things to food. A full rolling boil churns everything around, while a simmer moves the liquid just enough to cook evenly.
Most recipes that say to bring something to a boil then turn the heat down to a simmer. Skipping that second step is a common reason for tough stew meat, cloudy broth, split cream sauces and scorched pots.
How to do it
Bring it up on higher heat
Use medium-high heat to bring the liquid to a boil quickly.
Turn it down
Lower the heat until only small bubbles rise and break gently, mostly around the edges.
Adjust as it changes
Liquids thicken and heat up as they reduce, so turn the heat down a little more if bubbling picks up.
Lid on or off
Cover to keep the liquid in; leave it off to reduce and thicken the sauce.
Common mistakes
- Leaving a stew at a rolling boil, which makes the meat tough and dry.
- Boiling dairy-based sauces, which can make them split.
- Walking away from a thick sauce on high heat, which scorches the bottom.
