Feta cheese can become soft and melty when heated up, but it doesn’t melt down to a liquid state like some other cheeses. Why? Because feta cheese has a much higher acid content than other cheeses, which we will explain below in detail.
Unlike cheddar or other “highly melting” cheese, feta cheese has high moisture content and high acid content. What does this mean? It has a lower melting point due to the high acidity, unlike other easily melty cheeses.
High acidity levels in feta cheese cause the calcium to dissolve, which makes it difficult to melt. In a nutshell, when you try to heat up cheese that contains a high acid content, its protein bonds tighten and get rid of any water that can be found in the cheese.