Preheating your pan — Truth or Myth

Many of you may know that I really do not like it when “Culinary Myths” are passed down without any thought to whether those myths are really true or not. This happens at all levels from home cooks to experienced chefs. I have already written two Cooking Tips on a number of such culinary myths. In this Tip, I want to discuss another topic that falls into this category. That is whether or not you preheat your pan before adding the fat.

I was taught a certain way in culinary school and just accepted it as fact. However, when you start to do a deeper dive into this subject, it is not as clear cut. I was taught that you heat your pan before adding the oil. There are also other individuals, well-respected in the culinary world, that also advise that. Because of this, I have often taught this to those who have attended my cooking classes. I began to wonder about the accuracy of this recommendation and decided to investigate.

There are two main reasons why preheating the pan before adding oil is advised. They are fat degradation and food sticking. You may also hear arguments about even food cooking and the pores in a pan.

Fat degradation

Some feel that the longer the fat is in the pan being heated (such as would happen when you add the fat to the pan before heating it), the more likelihood there is of that fat breaking down into unpleasant and even unhealthy compounds.

While this may make sense on the surface, it really doesn’t when one considers that the fat will not start to deteriorate until it reaches its “smoke-point”. It doesn’t matter whether that fat is added to a cold or hot pan. All that matters is the temperature at which the respective fat starts to break down.

Here is a chart on smoke-points of various types of fat. As you can see from that chart, other than butter, extra-virgin olive oil, coconut oil and some nut oils, the smoke-points are above 360°F and often as high as 500°F. This is higher than you are going to use in most cooking situations. Therefore, the concern for fat degradation as a reason to preheat your pan really doesn’t stand up to scrutiny in most cases.

Food sticking

This reason goes like this adage – “Hot Pan, Cold Oil, Food Won’t Stick”. What makes food stick to a pan is if the pan isn’t hot enough. If you do not add your food until your pan is hot, it really doesn’t matter whether you put the oil in at the beginning of heating or after the pan is hot. If you put your food into a cold pan, it will stick no matter if there is oil in it or not.

If you heat your pan and add the “cold” oil (more like room temperature oil), the oil heats up immediately. You can see this for yourself by watching how quickly the oil starts to shimmer. As others have pointed out, the adage is incorrect in and of itself as in reality, it is “Hot Pan, Hot Oil, Food Won’t Stick.”

Pores in the pan

I was taught in culinary school that if you preheat your pan dry, the pores in it (microscopic holes) will close up allowing the oil to glide on the surface and prevent sticking. The proponents of this argue that if food is added before these pores close up, the pores will grab onto the food and cause sticking. However, the closure of the pores is a matter of the pan heating up, not when you add the oil. So, once again, make sure your pan is at the right temperature before adding the food.

Even cooking

If you put your fat into a cold pan and heat it, you will notice that the fat tends to pool around the side. Because of this, the temperature of your pan is going to be different at different spots. Some experts feel this will lead to uneven cooking. However, the difference in pan temperature occurs regardless of when you add the oil. It may be a good reason to make sure you are cooking with good quality cookware, which is more likely to heat evenly, but it is not a reason for preheating the pan before adding the oil.

With all that in mind, what is the home cook to do? For most situations, whether or not you preheat your pan before adding the oil really doesn’t matter. There are a few exceptions to this declaration. Here are some guidelines.

1. Almost always make sure your pan is hot before adding the food. Add the oil either before you start heating the pan or after it is hot but do not add the food until all is hot.
   
   
2. One exception to this is if you are cooking on a very gentle heat, such as sweating veggies or cooking fresh herbs or spices. In this case, you do not need to wait until your pan is hot. You can add both oil and ingredients to a cold pan and proceed to cook over a gentle heat. Many chefs feel that slower, more gentle heat/oil draws out more flavor. Too much heat can deactivate some flavor-producing enzymes in the allium family (onions, garlic) and/or drive off aromatic/flavorful essential oils in the herbs and spices.
   
   
3. If you want to sear a piece of protein to get that wonderful, flavorful crust, you may want to heat your pan first and then add the oil. If you have heated your pan so that it is above the smoke-point of your preferred fat, this will minimize the time that fat is in the extreme heat. Realize though, that fat degradation starts immediately upon reaching the smoke-point. If you are using something with a low smoke-point (such as butter) heat your pan, add your butter, add your protein and cook quickly. Another option is if you are using oil, you can brush the oil on the protein before putting it in the hot pan. That also leads to less splattering.
   
   
4. If you are pan frying or deep-fat frying, this takes much more oil than the typical sauteing or searing process. It could be quite dangerous to add this amount of oil to a hot pan. You are much better off adding the oil to a cold pan and heating them together.
   
   
5. The type of pan makes a difference.
   • Never pre-heat a dry non-stick pan. High heat can quickly cause the coating on such a pan to break down. Although non-stick pans do have their place (cooking eggs, making crepes, cooking delicate fish), they should not be used for any high-heat application.
   • Although rare, a cast-iron pan could crack if heated dry.
   • The thermal shock of adding cold oil to a preheated enameled cast-iron pot could cause cracking.
   • Check the instructions from your cookware manufacturer. Some advise against heating a dry pan.

So, there you go – another Culinary Myth busted. See my other two Tips (Part 1, Part 2) for more culinary myths. Have your ever heard anything about cooking and/or baking that you want investigated? Let me know.