9. Heat

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Cooking is a process of transformation, and one of the most common tools we use to create that transformation is heat.

Many recipes will list very specific heat levels (high heat on the stove, 350°F in the oven, etc). While these can be helpful guideposts, the more important meta-skill is understanding different types of heat and how they affect your food. Once you know this, you’ll be able to pick and choose which techniques you use without having to rely on recipes.

Heat performs a lot of different roles in cooking. It makes food more digestible and safe to eat, it changes textures, it enhances existing flavors, and it creates entirely new flavors. Understanding the role heat plays (and how it works) is important because it helps you decide how to cook your food and it guides your decision-making throughout the cooking process.

My first professional cooking job was at an open-fire restaurant that didn’t have any stoves. We only had a grill and a wood-fired oven. There were no temperature dials, so all of our cooking was based on feel and intuition. This experience really elevated my cooking because I was able to move away from relying on specific heat levels listed in recipes and learned to rely on my own instincts. This is really important, because the directions listed in a recipe aren’t always correct! If a recipe tells you to cook something in a pan over high heat, but you notice that your food is burning, you need to turn the heat down. Heat management is a very important skill in cooking, and it’s something that requires you to pay attention and use your senses to do well.

Instead of thinking about the heat levels a recipe gives, you should think about the types of heat being used, what you’re trying to accomplish, and then use the sensory feedback you’re getting to adjust in real time.

In this lesson, we’ll cover two important topics:

• The different types of heat and the reactions they produce.
• The relationship between heat and moisture.

Let’s dive in!

There are two major categories of heat that you need to understand: direct vs. indirect, and wet vs. dry. Direct heat and indirect heat pertain to the relationship between the heat source and the food. Wet heat and dry heat pertain to the medium used to transfer the heat.

Direct Heat and Indirect Heat

The advantage of direct heat is that it’s one of the fastest cooking methods, especially when high heat is applied. It’s also a great way to achieve a sear and/or browning.

The advantage of indirect heat is that it provides gentle, even cooking. Because the heat is applied from all sides, the food is more likely to cook evenly than if it is applied directly to one side.

Wet Heat and Dry Heat

Wet heat cooking methods involve the use of liquid or steam in the cooking process. This could be water, broth, wine, or other types of liquid. In these methods, heat is transferred to food via the liquid, and the temperature doesn’t rise above the boiling point of water, which is 212°F degrees or 100°C.

Boiling, steaming, braising, poaching, and simmering are all wet heat techniques.

Dry heat refers to any cooking method that doesn’t use liquid as its medium. This includes things like baking, roasting, grilling, frying, searing, and sautéing.

Interestingly (and perhaps counter-intuitively), cooking methods that utilize oil (searing, frying, sautéing, etc) are considered forms of dry heat. The oil, once heated, acts more like a surface than a liquid. So these methods are a form of direct, dry heat.

Because dry heat doesn’t use liquid as a medium, there’s no upper limit on the temperatures that can be used. So dry heat is always used for certain types of high-heat cooking where you want to produce reactions that can’t happen below the boiling point of water (we’ll cover this more below).

There’s a really important concept in cooking (and one you can use to impress your chef friends) called Maillard reaction.

The Maillard reaction is an organic chemical reaction in which reducing sugars react with amino acids to form a complex mixture of compounds. It’s a fancy way of saying browning– the process that occurs when you sear a steak, toast a piece of bread, or roast a potato. We seek out this reaction because the process produces compounds that cause the food being browned to develop entirely new, complex flavors.

You can see this in action in the photos below, where the steak has undergone transformation via the Maillard reaction. The high, direct, dry heat from the searing process causes browning— not only does this create a crust that lends a nice texture, but it also produces amazing new flavor.

We seek out the Maillard reaction constantly in cooking because it produces such flavorful compounds that make food taste great.

In order to achieve the Maillard reaction (and to use heat successfully), it’s important to understand the relationship between heat and moisture.

The Maillard reaction can only happen with dry heat. The reason is that wet heat (by definition) can’t exceed 212°F, which is the boiling point of water. Browning happens at temperatures much higher than that (usually 280°F and above), so it can only be achieved with dry heat above a certain temperature.

You can see this in action with a few easy-to-understand examples.

Below are two eggs— one is poached and the other is fried. The poached egg is cooked using wet heat, so no Maillard Reaction occurs. Because of this, no new flavor compounds are created. The end result is a concentration of the existing flavors in the egg— a poached egg tastes really “eggy” and has a soft texture.

The fried egg is cooked using dry heat. As you can see from the photo, significant browning has occurred, which means new flavor compounds and textures have been created. The fried egg has more complexity and a totally different flavor profile.

You can also see this with cooked broccoli. The photos below show broccoli cooked two ways— boiled in the first photo and roasted in the second. The boiled broccoli is cooked with wet heat, so it concentrates the existing flavor of the broccoli. The roasted broccoli is cooked with dry heat, so browning occurs and introduces more complex flavors and textures.

Browning can occur via direct or indirect heat, but only if it’s dry heat and the temperatures are quite hot. This is why I constantly tell cooks that they shouldn’t be afraid of high heat— some of the best flavors and textures are only produced via very high temperatures!

If you want softer textures and more concentration of existing flavors, wet heat techniques are what you want to use. If you want browning, crispy textures, and more complex flavors, you need to use dry, high heat.

It’s important to understand these concepts because they can help you get the outcome that you’re seeking as you cook. Each of these heat categories, when applied, has its own advantages. But oftentimes in cooking, we apply a combination of these methods to achieve our desired outcome.

Using Direct Heat

Direct heat puts your food directly in contact with the food source. It’s the most intense form of cooking heat, and it allows for fast cooking. At higher temperatures it results in browning and Maillard reaction, creating new flavor compounds.

Apply direct heat when:

• You want to cook quickly: Direct heat is high and immediate, making it ideal for quick-cooking foods like fish fillets, tender steaks, or vegetables.
• You want to sear or really brown your food: Direct heat is what produces the most intense Maillard reaction, adding a ton of flavor.
• Your food is thin or small: Smaller, thinner pieces of food can handle the intensity of direct heat without getting overcooked.

Searing a steak to develop a crust on the outside, deep frying potatoes, sautéing onions, and grilling asparagus are all examples of direct heat in action.

Using Indirect Heat

Indirect heat cooks food gently and more evenly by surrounding it rather touching it directly. It’s less intense than direct heat and results in more even cooking. It also allows for more gentle, longer forms of cooking that can lead to the development of nice flavors.

Indirect heat can be wet (poaching) or dry (roasting), so it can produce different reactions. If you want browning, use indirect, dry heat at high temperatures.

Use indirect heat when:

• You're cooking large or tough cuts of meat: Indirect heat is perfect for slow, low-temperature cooking that breaks down tough connective tissues in foods like roasts, briskets, or pork shoulders.
• You're looking to cook food evenly: If you're working with a larger piece of food where you’re seeking even cooking, you want heat to penetrate from all sides. Indirect heat is best for this.
• You want to avoid burning or drying out food: Because indirect heat is less intense, it's less likely to burn or dry out food, making it a good choice for delicate foods or dishes that need to retain moisture.

Finishing a steak in the oven after searing it, roasting sweet potatoes, and poaching eggs are all examples of indirect heat.

Using Dry Heat

Dry heat uses hot air or fat to cook food without the addition of water or liquid, so it promotes browning and crisping.

Use dry heat when:

• You want to create a flavorful crust or crispy textures: Dry heat can create a flavorful crust on food through caramelization and Maillard.
• You're cooking tender cuts of meat or fish: High heat can quickly cook and brown these foods without overcooking them.
• You want to induce browning: Dry heat is ideal for cooking vegetables or meats where your goal is to create new complex flavors and textures via browning.

Roasting vegetables, searing pork chops, and frying eggs are all examples of using dry heat.

Using Wet Heat

Wet heat allows for even cooking, concentrates existing flavors, doesn’t introduce new flavors via browning, and can be a more gentle form of heat, especially if applied at lower temperatures.

Use wet heat when:

• You're cooking grains or legumes: These foods absorb water as they cook, making them ideal for methods like boiling or simmering.
• You're cooking tough cuts of meat: Braising and stewing are great for tenderizing tough cuts of meat, as the moisture helps break down tough muscle fibers.
• You want to keep food moist and prevent it from drying out: Poaching and steaming are gentle cooking methods that can keep delicate foods like fish or chicken breast juicy and tender.
• You want to preserve existing flavors in food: Because wet heat never induces Maillard, foods cooked this way tend to have less complexity and more intensity of their core flavors.

Cooking pasta, making a stew, and boiling carrots are all examples of wet heat.

Combining Heat Types

Oftentimes when we cook, we’ll combine various forms of heat to produce the outcome we want.

For example— there’s a recipe in this course for reverse-seared steak. With this method we start by roasting the steak at a low temperature in the oven (indirect, dry heat), which allows it to cook evenly and gently to get to the right internal temperature. Then we sear it (direct, dry heat) which allows us to get deep browning and a nice cruse on the outside. Indirect heat is used for even cooking, and direct heat is used for intense flavor and texture development.

There’s also a recipe for braised short ribs. In this case, we start by searing the short ribs in a hot pan (dry, direct heat) to develop browning. Then we put them into a braising liquid and slow-cook them (wet, indirect heat). The direct dry heat allows us to achieve the Maillard reaction, and the wet indirect heat allows us to slowly, gently, and evenly cook the meat without drying it out.

Once you understand which outcomes are produced by which types of heat, you can choose the combination of heat types and cooking methods that will produce your desired result.

As a general rule of thumb:

• Direct heat is more intense, indirect heat is more gentle and even.
• Dry heat allows for browning, while wet heat retains moisture and concentrates existing flavors.

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