What Is a Simmer in Cooking: Temperature & Technique Guide

A simmer in cooking is a gentle cooking method where liquid is heated to just below boiling point (185°F to 205°F or 85°C to 96°C), characterized by small bubbles rising slowly to the surface. Unlike boiling, simmering preserves delicate textures while allowing flavors to meld without breaking down ingredients.

Mastering the simmer unlocks professional-level cooking results at home. This precise technique transforms tough cuts of meat into tender masterpieces, develops complex flavors in sauces, and prevents delicate foods from disintegrating. Whether you're making a rich beef bourguignon or a delicate custard, understanding how to properly simmer separates good cooks from great ones.

Why Simmering Matters in Culinary Success

Simmering isn't just about temperature control—it's a fundamental technique that affects texture, flavor development, and nutrient preservation. When liquids reach a full boil (212°F or 100°C at sea level), the violent agitation can break apart delicate ingredients like poached fish or dumplings. Simmering provides the gentle heat needed for collagen in meats to slowly convert to gelatin without toughening proteins.

According to the Culinary Institute of America's Professional Cooking textbook, "simmering allows for the gradual extraction of flavors while maintaining the integrity of ingredients." This controlled heat environment enables complex chemical reactions that create depth of flavor impossible to achieve with higher temperatures.

Simmer vs. Boil: The Critical Differences

Many home cooks struggle to distinguish between simmering and boiling, leading to disappointing results. Here's how to identify each stage:

Cooking Stage	Temperature Range	Visual Indicators	Best For
Simmer	185°-205°F (85°-96°C)	Small bubbles rising slowly, occasional surface disturbance	Stocks, stews, sauces, delicate proteins
Full Boil	212°F (100°C)	Vigorous bubbling across entire surface	Pasta, potatoes, blanching vegetables
Rolling Boil	212°F+ (100°C+)	Constant, rapid bubbling that can't be stirred down	Quick cooking tasks requiring maximum heat

The American Council on Science and Health notes that simmering preserves more water-soluble vitamins in vegetables compared to boiling, as the gentler process reduces nutrient leaching. This makes it particularly valuable for health-conscious cooking.

Perfecting Your Simmer: Step-by-Step Guidance

Follow these professional techniques to achieve the perfect simmer every time:

1. Start with Proper Equipment

Use heavy-bottomed pots that distribute heat evenly. Thin pots create hot spots that cause localized boiling while other areas remain too cool. A Dutch oven is ideal for most simmering applications.

2. Control Heat Gradually

Bring liquid to a boil first, then reduce heat to maintain a simmer. Sudden temperature changes shock ingredients. Adjust burner settings incrementally—most home stoves require turning the knob to medium-low or lower for proper simmering.

3. Monitor Visual Cues

Look for these signs of a proper simmer:

• Small bubbles (about the size of pearls) rising steadily from the bottom
• Occasional larger bubbles breaking the surface
• Gentle movement in the liquid without violent agitation
• Steam rising steadily but not forcefully

4. Adjust for Altitude

At higher elevations, water boils at lower temperatures. In Denver (5,280 feet), water boils at approximately 203°F, meaning your simmer occurs at a lower temperature. Compensate by maintaining a slightly more active bubble pattern than at sea level.

Common Simmering Mistakes to Avoid

Even experienced cooks make these critical errors:

• Overcrowding the pot – Too many ingredients lower the liquid temperature, disrupting the simmer
• Walking away – Simmers require occasional monitoring as heat settings may need adjustment
• Stirring too frequently – Excessive stirring can break delicate foods; only stir when necessary
• Using the wrong pot size – Too large a pot causes rapid evaporation; too small creates uneven heating

According to research published in the Journal of Food Science, maintaining consistent simmering temperatures improves protein tenderness by up to 30% compared to fluctuating heat levels. This consistency is why professional kitchens use specialized equipment like steam tables for long-simmered dishes.

When to Choose Simmering Over Other Methods

Understanding when to simmer rather than boil or poach makes all the difference:

• Stocks and broths – Simmering extracts flavors without emulsifying fats (which happens with boiling)
• Tough meat cuts – Collagen converts to gelatin at 160°-180°F, requiring extended simmering
• Sauces and reductions – Gentle heat prevents scorching and separation
• Dairy-based dishes – Boiling causes curdling; simmering maintains emulsion

Food historian Harold McGee explains in On Food and Cooking that simmering became the preferred method for European stews during the 17th century when cast iron cookware became widely available, allowing for better heat control than earlier cooking methods.

Advanced Simmering Techniques

Once you've mastered basic simmering, try these professional methods:

Sub-Simmering for Delicate Foods

For custards and delicate fish, maintain a temperature just below simmering (160°-180°F). The liquid should show almost no movement, with only occasional tiny bubbles.

Active Simmering for Faster Results

When time is limited, maintain a slightly more active simmer (closer to 205°F) while monitoring closely to prevent boiling. This works well for vegetable-based soups where texture preservation is less critical.

Covered vs. Uncovered Simmering

Use these guidelines for lid positioning:

• Covered – For moist cooking, reduced evaporation, and faster heat penetration (braises, stews)
• Uncovered – For reducing liquids, concentrating flavors, and preventing overcooking (sauces, reductions)
• Slightly ajar – Best compromise for most applications, allowing some evaporation while maintaining temperature

The National Center for Home Food Preservation recommends specific simmering times for safe canning practices, noting that proper simmering temperatures are critical for destroying harmful bacteria in preserved foods.

Troubleshooting Your Simmer

Solve these common simmering problems:

Problem	Causes	Solutions
Liquid boiling violently	Heat too high, pot too thin, altitude effects	Reduce heat immediately, move to cooler burner area, use heavier pot
No bubbles forming	Heat too low, too much liquid, high altitude	Increase heat slightly, reduce liquid volume, check thermometer
Uneven simmering	Pot shape, burner size mismatch, hot spots	Use proper-sized burner, stir occasionally, rotate pot

Professional chefs often use a "simmer plate" – a metal disc placed between the burner and pot – to diffuse heat and maintain consistent low temperatures for extended simmering.

Perfect Simmer Applications

Apply your simmering knowledge to these classic dishes:

• French Consommé – Requires crystal-clear broth achieved through careful simmering without boiling
• Italian Risotto – Gradual addition of warm stock maintained at a gentle simmer
• Indian Curries – Spices bloom properly only at precise simmering temperatures
• Chocolate Ganache – Dairy must be heated to just below simmering to prevent separation

Mastering the simmer transforms your cooking from hit-or-miss to consistently excellent. By understanding the science behind this fundamental technique and applying these practical methods, you'll achieve restaurant-quality results with confidence. Remember: the difference between a good dish and a great one often comes down to perfect temperature control during the simmering phase.

What temperature is considered a simmer in cooking?

A proper simmer occurs between 185°F and 205°F (85°C to 96°C). At this temperature, small bubbles rise slowly to the surface without the vigorous agitation of a full boil. The exact temperature within this range depends on what you're cooking and your altitude.

How can I tell if my pot is simmering properly without a thermometer?

Look for small bubbles (about the size of pearls) rising steadily from the bottom of the pot. The surface should show occasional larger bubbles breaking through, with gentle movement in the liquid but no violent agitation. Steam should rise steadily but not forcefully. If you see a constant stream of large bubbles, it's boiling, not simmering.

Why is simmering better than boiling for making stocks and soups?

Simmering extracts flavors more gently than boiling, preventing fats from emulsifying into the liquid which would make stocks cloudy. The lower temperature also preserves delicate flavors and prevents toughening proteins in meats. Boiling causes violent movement that can break apart ingredients, while simmering allows flavors to meld gradually for a more complex, refined taste.

Should I cover my pot when simmering?

It depends on your goal. Cover the pot when you want to retain moisture and heat (for braising meats or cooking grains). Leave it uncovered when reducing liquids or concentrating flavors (for sauces). For most applications, leaving the lid slightly ajar provides the best balance, allowing some evaporation while maintaining temperature.

How do I prevent my simmer from turning into a boil?

Start by bringing liquid to a boil, then immediately reduce heat to low or medium-low. Use a heavy-bottomed pot for even heat distribution. If simmering unexpectedly becomes too vigorous, temporarily remove the pot from heat for 30-60 seconds. Consider using a simmer plate (heat diffuser) between the burner and pot for better temperature control, especially with electric stoves.