A simmer is when liquid is heated to roughly 185°F to 205°F, just below a full boil, with small bubbles gently and sporadically breaking the surface. It’s one of the most common instructions in cooking, and getting it right matters more than most people realize. Too low and your food barely cooks; too high and you risk tough meat, bitter sauces, and lost flavor.
What a Simmer Looks Like
The easiest way to identify a simmer is by watching the bubbles. You’ll see small, soft pockets of air rising from the bottom and sides of the pot, breaking at the surface every few seconds. The liquid moves gently but isn’t agitated. Think of it as quiet, lazy activity in the pot rather than the violent, churning motion of a boil.
A full boil, by contrast, produces large, forceful bubbles that continuously roll across the entire surface at 212°F. The difference is obvious once you’ve seen both side by side. If your pot looks like a hot tub on full blast, that’s a boil. If it looks like a glass of champagne with a few lazy streams of tiny bubbles, you’re in simmer territory.
The Different Levels of Simmering
Not all simmers are the same, and recipes sometimes specify which one they mean.
- Bare simmer (around 185°F): A bubble breaks the surface every few seconds. The liquid looks mostly still. This is what you want for long, slow-cooked stocks, delicate braises, and stews where you need hours of gentle heat without drying out the meat.
- Steady simmer (around 195°F): Streams of small bubbles rise consistently from the bottom. The surface has constant but gentle movement. Most recipes that say “bring to a simmer” mean this.
- Rapid simmer (around 200 to 205°F): More vigorous bubbling, with larger bubbles mixed in, but not yet a full rolling boil. Useful for reducing sauces when you want faster evaporation but still need some control.
Below a simmer sits poaching, which happens at 160°F to 180°F. At poaching temperatures, you’ll see little to no bubble activity at all, maybe a few wisps rising from the bottom. Eggs, fish, and chicken breasts do well at poaching temperatures because they’re delicate proteins that toughen quickly with too much heat.
Why Simmering Matters for Flavor and Texture
The difference between simmering and boiling isn’t just a few degrees. Those few extra degrees and the violent motion of boiling liquid can make food noticeably worse. Compounds in sauces and stocks can turn bitter at a hard boil. Aromatic flavors get driven off into the steam instead of staying in the pot. Fats can emulsify into the liquid, making a stock cloudy and greasy instead of clean and rich. Dairy-based sauces risk scorching.
For reductions, a slower simmer produces richer, more concentrated flavor than a rapid boil. Boiling breaks down solids more aggressively, which changes the texture and can leave you with a muddy, overworked sauce. The general principle: the longer and slower the reduction, the better the result.
Simmering is also critical for tough cuts of meat. Connective tissue in cuts like chuck roast, short ribs, and pork shoulder is packed with collagen, which starts breaking down into gelatin at relatively low temperatures, around 160°F and above. This breakdown is what transforms a chewy, tough piece of meat into something fork-tender. But it takes time. A gentle simmer gives collagen hours to dissolve gradually. A hard boil forces the muscle fibers to seize up and squeeze out moisture faster than the collagen can compensate, leaving you with meat that’s both dry and stringy.
How to Hold a Simmer on the Stove
Bring your liquid to a boil first, then reduce the heat until the bubbling calms to the level you need. On most stoves, a simmer lives somewhere between low and medium-low heat, but this varies by burner strength and pot size. A heavy-bottomed pot holds temperature more steadily than a thin one, which helps prevent the liquid from creeping back up to a boil.
Check in occasionally. Adding cold ingredients like vegetables or meat will temporarily drop the temperature, and the liquid may need a minute to recover. A lid traps heat and can push a simmer into a boil, so many recipes call for a partially covered pot, with the lid slightly ajar to let steam escape while keeping enough heat in.
If you don’t have a thermometer, your eyes are a reliable guide. Watch the bubbles. Small and occasional means you’re in the right zone. If the surface starts rolling with large, constant bubbles, turn the heat down.
Simmering at High Altitude
If you live above 3,000 feet, simmering behaves differently. Water boils at a lower temperature as elevation increases, dropping by roughly 1°F for every 500 feet above sea level. At 7,500 feet, water boils at about 198°F instead of 212°F. That means your simmer is also happening at a lower temperature, and food cooked by simmering or braising will take longer to finish.
This is especially important for meat, beans, and grains. Plan for extra cooking time, and be aware that slow cookers at high altitude simmer at a lower temperature than they would at sea level, which can affect both food safety and tenderness. Adding more liquid helps compensate for the faster evaporation that comes with high-altitude cooking.