Many have seen videos of people attempting to melt Kraft American cheese or another processed cheese slice by holding a lighter flame to the cheese, only to find that it resists melting and instead burns, or rather browns and chars. They juxtapose this with a lighter flame held to regular cheese and the cheese melts and drips. So, American cheese doesn’t melt and is therefore plastic, full of chemicals, and fake? Read on to learn the scientific facts of why American cheese responds to a direct flame differently than regular cheese. Reading time: 7 minutes.
Well if you are an American you know that Kraft American cheese melts quite nicely. You’ve probably made many a grilled cheese sandwich or cheeseburger using it. And, if you’ve ever used Velveeta cheese, which is made using the same process, to make a nacho dip, you know that it melts to a creamy, delicious goodness. So, what is going on here?
These rumors and images of American cheese ‘burning’ and not melting have been around for a while. Most recently, the hype was restarted by a YouTube channel called Blossom TV, which is known for posting fake videos designed to garner clicks.
If Cheese Doesn’t Melt It’s Fake?
This flame to processed cheese was depicted in a video entitled ‘Is Your Food Fake or Real?’ The fact that the processed cheese didn’t melt when exposed to a direct flame like the regular cheese was supposed to prove that it was fake cheese. The idea that if cheese doesn’t melt it’s fake is, to put it simply, made up.
Food scientist Ann Reardon already debunked this video, including the claims about processed cheese on her channel ‘How to Cook That.’ It may seem pretentious of me to weigh in at this point, but the reason I decided to is that 1) It may help reach a few more people, and 2) I found her explanation wanting and unclear.
Reardon explained that the melting problem had to do with the fat content of the cheese. She compared the label of some ‘American’ cheese to some regular cheese, finding that the regular cheese had more fat. It’s the fat content of cheese, she said, that governs its melting.
The cheese with less fat, therefore, did not drip and melt but instead burned. No disrespect is intended for Reardon. She had a lot to cover in the video and such a misleading demonstration was hardly worth devoting extra time. I love her videos, which are informative and entertaining. But here is a more detailed explanation.
Of Course American Cheese Melts!
Since processed cheese or pasteurized cheese product, as it’s more technically called, does indeed melt, this explanation needs some tweaking! What you will have noticed is that American cheese melts differently from, say, cheddar cheese.
American cheese melts and becomes creamy, but the fat does not separate from the solids. It stays nice and smooth! Other ‘natural’ cheeses, depending on the fat content and firmness, will separate, so that the fat becomes a liquid that is not bound with the solids. This can result in a clumpy, greasy mess sometimes, depending on how you use the cheese.
So, notwithstanding that all cheese is processed, so-called processed cheese and natural cheese both melt, but in different ways, with different properties. The ability of Velveeta cheese to melt into a perfect creamy dip that holds its emulsion is why we use it for nachos so often! You don’t have to add anything other than your salsa or other ingredients to get a perfect dip for your tortilla chips.
The magic word here is emulsion. What is different about American cheese is that it is cheese (cheddar) that is mixed with whey protein and other emulsifying ingredients.
These ingredients hold the fat together with the solids and resist letting it go, even when heat is applied. If you’ve ever made a bechamel or white sauce, you’ve made an emulsion. Mayonaise is also an emulsion. I’ll expand on this below.
What is an Emulsion?
Normally, if you mix liquid fat with another liquid ingredient, the two will not mix well. The fat and liquid will repel each other. Oil and water don’t mix! The fat or oil will form into large drops and will resist dispersing into the liquid solution.
A fat emulsion is a mixture of fat and other watery liquid where the fat is dispersed throughout into very small microscopic droplets. An emulsion is an evenly mixed or ‘homogeneous’ dispersion of, in this case, oil and water (or milk, etc).
We use such emulsions in cooking constantly. To make an emulsion, we add an emulsifying ingredient and use mechanical agitation to break up the fat droplets and mix them into the liquid. This occurs through a mechanical force called shearing. You can do this by whisking, using a blender, food processor, or handheld immersion blender.
Just mixing oil and water together is not enough. The two will quickly separate again. To solve this, an emulsifier is used. A common emulsifier in cooking is egg yolk. The key component of egg yolks is the phospholipid lecithin. One part of lecithin is a fatty acid that can bind with fat and another part is a choline group that faces outward toward the water.
The result is that the fat droplets are surrounded by this phospholipid and a water-loving part faces outward so that the oil droplet is both interacting with the water and staying away from other oil droplets.
The result is a stable mixture, although another stabilizer might be added to help things along. Mayonnaise, which relies on egg yolk, is an oil-in-water emulsion. It has more oil than water. If there is more water than oil, we have a water-in-oil emulsion. Margarine is a water-in-oil emulsion.
Kraft Singles use emulsifiers to bind the fat and proteins together. Natural cheese has no such emulsifiers. This, and not the fat content per se, is the reason for the effect we see in videos when the singles are exposed to direct flame. When you hold a flame to regular cheese, there is nothing to stop the fat from melting and dripping off, so it does this before the solids will start browning.
So, No, American Cheese is Not Plastic
When a direct flame is held to a Kraft Single, the fat and proteins stay tightly bound together and resist being separated. The milk solids begin to burn even while holding on to their fat. If you want a Kraft Single to melt properly, you need to use a lower heat and let it melt slowly enough.
This all just means that Kraft Singles have different properties than regular traditional cheese. It does not mean that American cheese is bad for you. It certainly does not mean that it is plastic. By the way, why doesn’t anybody put two and two together? Different plastics behave differently when exposed to direct flame. Some melt. So, the explanation makes no sense in the first place.
Now, it is not unusual for any cheese to fail to melt when exposed to extremely high heat. A piece of cheddar cheese placed directly onto a hot skillet will not melt but rather brown and turn crispy. This can be used to great effect as these little crispy cheese pieces are delicious and nutty.
