The story (and science) of processed cheese

Are you a fan of cheese burgers? If so, what type of cheese do you put on top? Do you buy those individually wrap thin ‘cheddar’ slices?

I’m not a fan of cheese burgers myself, but we do always have a small pack of exactly those slices of ‘cheese’ in our fridge. This cheese seems to be very different from our ‘regular’ Gouda cheese here in the Netherlands. A little search learned me this is a whole different food category: processed cheeses. Processed cheeses are a great example of how industry learned to find ways to better standardize their products and tweaking them for the exact purpose they needed. So it’s time I started to understand what exactly processed cheese is and how it’s made.

Some legislation & definitions

Just like me, you might not yet know what processed cheese actually stands for. It took me a while to figure out, but in its core processed cheese is a food that not only contains cheese, but may also contain other (non-)dairy ingredients and will generally contain some sort of emulsifying salts.

As a reminder, ‘natural’ cheese is made from milk. During the cheese making process, proteins (casein) in milk are agglomerated. The milk curdles as a results and from these curds cheese is made. There are several ways to initiate the curdling of milk for making cheese, you can use enzymes or lower the pH (=increase the acidity) of the milk.

Cheese product properties

During cheese making a lot of water is removed and the resulting cheese is a gel of proteins and fats in some water. These gels are generally not very stable. For instance, when cheese is melted fat has a tendency to leave the cheese. When you cool the cheese back down the cheese will have split.

As we learned when zooming in on the cheese layer on top of a spinach quiche, ‘natural’ cheeses all behave very differently when melted and heated in the oven. Some will bubble, others will turn brown and some will simply burn. If you want the flavour of a cheese that burns easily, but don’t want it to burn, that’s when you start considering processed cheeses!

Despite the fact that cheese making can be done on a large scale, natural variations in the ingredients can still slightly influence the outcome of the cheese. What’s more, cheese is quite an expensive product. If you’ve made your own homemade cheese once you know that 1 liter of milk will only give you very little cheese. What’s more, a lot of cheeses have to be ripened to develop their flavour.

finished paasstol with cheese, butter and almond paste center
Bread (with raisins, almonds and almond paste) best eaten with a slice of cheese.

What is processed cheese?

In comes the processed cheese. Processed cheese does contain cheese, but the cheese has been mixed and melted with other ingredients. This allows manufacturers to reduce the costs of the cheese (by adding cheaper ingredients) but also to tweak the processed cheeses further. By mixing different cheese they can get the specific flavour profile they’re looking for. The additional ingredienst can also be used to modify the properties.

Some examples of processed cheese are: ‘cheese’ from a tube, spreadable cheese spreads,  ‘La vache quite rit’, cheese strings, etc. You will notice they all tend to have properties that ‘natural’ cheese are not capable of, such as being dosed from a tube or dipped into.

Processed cheese & melting

An important characteristic of processed cheese is how it behaves during melting. Due to the use of so-called emulsifying salts, processed cheeses have a very homogeneous structure. The fats and proteins are mixed very well in the cheese. As a result, the fat will not leave the cheese and form a separate layer as it does for regular cheeses. This is one of the reasons processed cheese is often used in frozen pizzas, lasagnas, etc.

How is processed cheese made?

Where regular cheese making starts with milk, processed cheese production actually starts with cheese! The manufacturer will choose one or several cheeses they want to include in the processed cheese. These cheeses are thne grated and melted. The melted cheese is mixed with other ingredients again. Common additional ingredients are (which are allowed depends on the country the cheese is made and sold):

  • Milk fats: for instance cream
  • Other dairy ingredients: whey proteins are quire common
  • Emulsifying salts: these modify the proteins in the cheese such that they are dispersed better which makes for this very homogeneous product.
  • Salt (processed cheese tends to contain more salt than regular cheese)
  • Colourants and spices

The ingredients are heated and mixed to make a stable mass. Heating is required to pasteurize the product. Both the way the processed cheese is processed as well as the ingredients strongly influence the final properties. In has been found that the cook time, cook temperature, extent of mixing as well as rate of cooling all influence the final processed cheese properties.

The resulting product can then be shaped in packed in any shape or size. For instance, those slices to put on  your cheese burger.

Why processed cheese?

In the previous paragraphs we’ve already touched upon several reasons why processed cheese is made: lower production (and ingredient) costs, better (or other) melting behaviour and a whole new flow behaviour (can be dipped, sqeeuzed through a bottle).

Other important reasons for industry is the ability to standardize the production even further. By mixing cheeses you can obtain the exact same flavour profile for every batch. What’s more, to get flavour development you don’t have to ripen the complete cheese. Instead, you mix in some ripened cheese to get some ripened cheese flavour.

Ever looked at the storage conditions for processed cheese? Becuase of the pasteurization (the heating process) and composition they can often be kept out of the fridge. Thus, their shlef life is a lot longer. What’s more, the flavour won’t change much during storage either. Regular cheeses keep on developing flavour during storage (and are a lovely place for moulds to grow), processed cheeses don’t.

All in all, processed cheese allows producers to tweak cheeses to get the optimal desired properties of the cheese for their applications. Should it melt well? Should it be firm to be grated or sliced on processing equipment?

That is what gives you those individually wrapped yellow/orange slices for your hamburgers. No worries if you don’t use them for months, they can often be kept for long. Now you know why that is.

Sources

Michigan Dairy Review, on the history of processed cheese. Very extensive scientific article discussing various aspects of processed cheese.

I took me quite a lot of trouble to find the propper definitions and regulations for processed cheese, for those interested in reading more, have a look here:

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