Simmering vs Boiling: Key Differences & When to Use Each

Simmering and boiling are two of the most fundamental cooking techniques, yet many home cooks use them interchangeably—often with disappointing results. Understanding the difference between a gentle simmer (about 185–205°F / 85–96°C) and a rolling boil (212°F / 100°C at sea level) is the key to perfectly cooked grains, tender meats, and clear broths. This guide explains exactly how to achieve and maintain each heat level, and when to use one over the other for the best texture and flavor.

Ingredients

Water or broth: 4 cups (960 ml) for boiling pasta or vegetables; 6 cups (1.4 L) for simmering a soup or stew
Salt: 1 tablespoon (18 g) for boiling water (optional, for pasta or vegetables)
Your choice of food to cook: e.g., 8 oz (225 g) pasta, 1 lb (450 g) chicken thighs, or 2 cups (400 g) rice
Aromatics (optional): 1 bay leaf, 2 cloves garlic, or 1 onion, halved

Instructions

For boiling: Fill a large pot with water (or broth) and add salt if using. Place over high heat, uncovered, until large bubbles break vigorously across the entire surface and steam rises steadily. This is a rolling boil at 212°F (100°C). Use this for pasta, blanching vegetables, or hard-cooking eggs.
For simmering: Bring the liquid to a boil first, then reduce the heat to medium-low or low. You should see small bubbles gently rising to the surface, with occasional wisps of steam—not vigorous bubbling. The liquid should be between 185°F and 205°F (85–96°C). Use this for soups, stews, braises, and cooking grains like rice or quinoa.
Adjust the heat as needed: If the liquid starts boiling too hard, lower the heat or move the pot partially off the burner. If it stops bubbling entirely, increase the heat slightly. A true simmer is a lazy, steady stream of bubbles—not a full boil and not still.
Cook your food: Add your ingredients to the liquid at the correct stage. For example, add pasta to a rolling boil; add chicken to a simmering broth. Maintain the appropriate heat level throughout cooking, adjusting as needed.
Check doneness: For meats, use a food thermometer to ensure they reach the USDA FSIS safe minimum internal temperature: poultry (including duck) 165°F (74°C), ground meat 160°F (71°C), whole cuts of beef, pork, veal, lamb, and goat 145°F (63°C) with a 3-minute rest, and fish 145°F (63°C). For vegetables, test with a fork until tender. For pasta, taste for the desired doneness.
Finish and serve: Remove from heat and drain or serve directly from the pot. If you simmered a soup or stew, let it rest for a few minutes before serving to allow flavors to meld.

Tips

Use a thermometer for precision: If you’re unsure whether you’re simmering or boiling, use an instant-read thermometer. Simmering is 185–205°F (85–96°C); boiling is 212°F (100°C) at sea level. At higher altitudes, water boils at a lower temperature, so adjust accordingly.
Don’t boil what should simmer: Boiling tough meats or making stock at a rolling boil can make the liquid cloudy and the meat tough. Simmering gently extracts flavor without agitation.
Cover or uncover: Cover the pot to bring liquid to a boil faster, but uncover when simmering to allow evaporation and concentration of flavors. For rice, cover tightly during simmering to trap steam.
Salt the water for pasta: Salting boiling water (about 1 tablespoon per 4 cups) seasons the pasta from within. For simmering soups, add salt sparingly at first—you can always add more later.

Serving Suggestions

Use your perfectly simmered or boiled creations as the base for a meal. Serve simmered chicken stew with crusty bread and a green salad. Toss boiled pasta with your favorite sauce and grated cheese. Simmered rice pairs well with stir-fries or curries. Boiled potatoes can be mashed or turned into potato salad.

Variations

Shallow poaching: A gentle simmer (around 160–180°F / 71–82°C) is sometimes called poaching. Use it for delicate foods like fish fillets or eggs.
Blanching: Boil vegetables briefly (1–3 minutes), then shock in ice water to preserve color and crunch. Great for green beans or broccoli.
Parboiling: Boil potatoes or root vegetables for a few minutes before roasting to speed up cooking and achieve a crispy exterior.
Broth vs. stock: Simmer bones and aromatics for stock (longer, for flavor and gelatin), or simmer meat and vegetables for broth (shorter, for a lighter flavor).

Storage and Reheating

Refrigerate any cooked food within 2 hours of cooking. Most cooked dishes (soups, stews, pasta, rice) will keep for 3–4 days in an airtight container in the refrigerator. To reheat, add a splash of water or broth to restore moisture and warm gently on the stovetop over medium-low heat, or in the microwave in 30-second intervals, stirring between. For soups and stews, reheat until bubbling (at least 165°F / 74°C for leftovers). You can freeze most simmered dishes for up to 3 months; thaw overnight in the refrigerator before reheating. Pasta is best eaten fresh, but you can freeze cooked pasta tossed with a little oil for up to 1 month.

Frequently Asked Questions

How can I tell if my liquid is simmering without a thermometer? Look for small bubbles that rise gently to the surface and break softly, with occasional wisps of steam. The surface should be quivering, not churning. If you see large, rapid bubbles that disturb the surface, it’s boiling.

Can I boil something and then lower the heat to simmer? Yes, that’s the standard method. Bring the liquid to a boil first to heat it quickly, then reduce the heat to establish a simmer. This is faster than trying to bring it to a simmer from cold.

Why does my soup become cloudy when I boil it? A rolling boil agitates the ingredients, causing fats and impurities to emulsify into the liquid, making it cloudy. Simmering keeps the liquid clear. For a clear broth, always simmer gently and skim any foam that rises.

Does altitude affect boiling and simmering? Yes. At higher altitudes, water boils at a lower temperature (e.g., about 202°F / 94°C at 5,000 feet). This means simmering will also be at a lower temperature. You may need to cook foods longer at altitude, and boiling times for pasta and eggs may increase.

Is it okay to simmer with the lid on? Yes, but it will reduce evaporation and increase pressure slightly, which can raise the temperature a bit. For most simmering, it’s better to leave the lid slightly ajar to allow steam to escape and flavors to concentrate. For rice and grains, a tight lid is essential to trap steam for even cooking.

What’s the difference between simmering and poaching? Poaching is a lower-temperature technique (160–180°F / 71–82°C) where the liquid barely moves, with tiny bubbles on the bottom. Simmering is slightly hotter (185–205°F / 85–96°C) with small bubbles rising to the surface. Poaching is for delicate foods like eggs and fish; simmering is for tougher items like meats and root vegetables.

More recipes to cook

Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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