Cheese curds. Halloumi. Kefalograviera. What is one thing that they all have in common? They squeak! And we love them for it right? But have you ever wondered why cheese curds are squeaky?
SEE ALSO: Why is Mozzarella so stretchy when melted? →
The molecular structure of cheese
Those three cheeses mentioned above all owe their squeakiness to their molecular structure. More specifically, it comes down to the intact protein structure and the amount of bound calcium. Let me explain.
By now, we’ve extensively covered the fact that cheese is protein. And one of the main differences between young cheese and mature cheese is how the protein structure goes from being intact (young cheese) to being much looser (mature cheese) over time. The reason for this is proteolysis. This is the process by which the protein breaks down over time.
Calcium in cheese
Moreover, the calcium from milk can either be stuck to the protein structure, or dissolved in the cheese. The main factor that determines the state of the calcium is pH (level of acidity).
A cheese with higher pH (less acidic) will have more bound calcium. On the other hand, a cheese with lower pH (more acidic) will have more dissolved protein. What does all of this mean for cheese?
What happens when you bite into a squeaky cheese?
Well, young cheese curds, Halloumi or Kefalograviera all have a strong, intact protein structure and a strong network of calcium bound to the protein. And, you’ve guessed it! When you bite into cheese curds, those structures rub against the enamel in your teeth, making a squeaking sound.
If you’re a cheese curd lover, you might also have noticed that a few days after they’ve been made, the curds tend to lose their squeak. The reason for that is that the starter culture used to make the curd continues to break down lactose into lactic acid. And, as the curds get more acidic, the calcium shifts from being bound to being dissolved. And, there goes the squeak!
Now, time for the big question. What’s your favourite squeaky cheese? Let me know in the comments.
Jonah is a a hipster, eco-warrior and slow food afficionado. Coming from a scientific background, Jonah has a particular interest in cheese science. And yes, he loves a good cheese pun!
