Cheesemaking 101: Ripening

Ripening
The last, and in many ways the least understood, step in making cheese is ripening, which is the process whereby a salty, white mass of curd with a quite unappealing texture is transformed into something worth eating. However, fresh cheeses are ready to be eaten without any ripening. Just as they are, they have a quality of freshness that is hard to beat; but they also have a very short shelf life, perhaps no more than four or five days.

To keep a fresh cheese beyond this, they need to be packaged or protected from air in some other way. Our answer to preserving freshness in the soft cheese is to vacuum-pack it: once all the air is removed, almost no bacterial activity can take place and the cheese changes very little over its two month shelf life, provided that it is kept refrigerated.

At the end of the 'make' process, most cheeses look very much the same; it is what happens during the 'ripening' process that makes the difference. Almost all ripening takes place in a cool (but not cold) and humid environment, the idea being to prevent the cheese from drying out while keeping it warm enough to allow the breakdown of the fats and proteins to proceed.

The main categories of ripened cheeses are:

Surface-ripened cheeses, like Brie and Camembert, in which the penicillin mould which grows on the outside of the cheese acts as the ripening agent. Ripening takes place from the outside in: you can often detect a difference in texture between the centre of the cheese (the least ripe part) and the smoother and creamier outer part just beneath the rind.

Washed rind (or smear-ripened) cheeses, like Epoisses, Oka and Limburger. These are typically the very strong smelling cheeses that are hard to hide in your luggage and avoid detection by Customs officials. However the flavour of this type of cheese is generally much less powerful than the aroma, particularly if you cut off the outer rind. As the name implies, these cheeses are rubbed during ripening with some kind of liquid, which can be anything from salt and water to wines and spirits flavoured with herbs and spices. The characteristic orange colour (and powerful aroma) of these cheeses comes from the addition to the washing liquid of a bacterium called Brevibacterium linens.

Natural rind cheeses are those cheeses in which the outside of the cheese has simply been allowed to dry out and form a crust. Included in this group are Parmesan (Parmigiano-Reggiano), Gruyere, tomme de Savoie, Stilton, and many, many others. During ripening the rinds of these cheeses are brushed to remove the grayish moulds which typically grow on the outside of the rind (or, in the case of Parmesan, rubbed with oil).

Waxed cheeses, including Gouda and some Cheddars, are so treated to protect against mould growth on the outside of the cheese. Other forms of protection include silver foil (Roquefort and several other blue cheeses), cheesecloth (traditional Cheddars) and vacuum bagging (used for some modern cheeses, particularly where there is a shortage of ripening space).

Brine ripening, of which feta is far and away the best known example, is actually a misnomer. The original purpose of immersing the cheese in brine (a salt and water solution) was to preserve its freshness. Feta may be aged in brine, but it is not being ripened in the normal sense because of the absence of air.