What types of cheese are considered fresh and what do they have in common?

The term "fresh cheese" encompasses a very long list of varieties, including mozzarella, queso fresco, halloumi, ricotta, crème fraîche, mascarpone, paneer, fresh goat cheese, and feta. Cream cheeses also fall into this category, and soft cheese is often the same as queso fresco.

These cheeses are not interchangeable, because the variety of flavors and textures is enormous: you couldn't substitute halloumi with paneer, a fresh goat cheese or mascarpone without probably causing a disaster.

Despite this diversity, they share some characteristics. They don't ripen: they are packaged and ready to eat as soon as they are produced. They usually have a light, creamy, or milky flavor, sometimes slightly acidic, and in the refrigerator they only keep for one or two weeks after opening.

Their production is also similar. The process begins with milk, to which starter cultures are added to thicken it, a stage sometimes called "ripening." During this stage, the lactose is converted into lactic acid. Some cheeses are made with rennet, although softer cheeses, such as cream cheese and certain mozzarellas, do not use it.

The type of milk greatly influences the final result. Goat's and sheep's milk are generally higher in fat than cow's milk, and goat's milk imparts a more acidic flavor, so its cheese can give the pizza a tangy touch. Feta and mozzarella are usually preserved in brine, which also adds flavor, although sometimes the brine is simply water.