Cheese Matters: Bloomy Rinds

Ever wondered why the much-loved Brie-and Camembert-style cheeses get that white bloomy coating on the outside surface? Have you ever pondered why, when aged, they become all soft and gooey on the inside? Firstly let’s get the jargon right.

The white fluffy exterior is referred to as the rind; bloomy rind or white mould, and the inside of the cheese is commonly known as the paste or pate. The rind doesn’t magically appear, in fact, us cheesemakers go to great lengths to get it there. For most, it is a fine powdery substance referred to as mould or an adjunct, it comes in little sachets that cheesemakers add directly to the milk.

Each sachet contains millions of little spores. This powdery magic has a malty aroma and is technically know as Penicillium candidum. We like it to grow without fuss: quickly, evenly and without too much blemish. Perfect world. Predominately produced in European countries, this potent powdery cocktail of moulds can contain hundreds of different strains. Like any mould, it requires special conditions to flourish.

It is no different to the common pesky household mould. Cheese moulds perform best when in humid and moist environments, appearing on the surface of young cheeses – in some cases less than 10 days after being sprinkled into milk during the first part of the cheesemaking process. These concentrated moulds will out grow any other unwanted mould (providing all the mouldy environmental stars align).

The rind of these cheeses is a thriving microbial community. A single gram contains 10 billion microbial cells, a mix of bacteria and fungi that contributes to a delicious and sometimes funky flavor. But even though humans have been making cheese for thousands of years, sadly we know very little about how these moulds interact.

Partly, the role of the mould is to protect the young cheese from insects, harmful bacteria and rogue moulds. It also makes the cheese easy to handle, but the two vitally important gastronomic functions of the mould is to add flavour and to ripen the cheese. Moulds are living organisms that require food. When they reside on the surface of a cheese they spend their living cycle penetrating the rind.

This process is referred to as proteolysis and, in simple terms, means the roots of the mould penetrate the cheese breaking down the protein and lactic acid in the paste, this results in the paste becoming soft. That is why, when left to their full term or best before, these cheeses generally become soft gooey and ripe. In this case, the mould has had enough time to complete its very important work. In addition to all this funky behind the scenes stuff happening inside that humble cheese is what happens to the flavour as all this is going on.

As the paste liquefies, it reacts with the cultures, minerals and water in the cheese paste to produce robust flavours and complexities. If you cut the cheese in half before the work is completed, you will break the cycle and the cheese will never ripen to its full potential. Traditional Brie was always made in large wheels, sometimes 35cm diameter and relatively thin, this allowed a larger surface area for the mould to grow and resulted in very effective ripening.

On the other hand, traditional Camembert was made in small rounds, slightly thicker and squat, and quite often they would have a slightly chalking centre where the mould expired before it could reach the centre of the dense paste. Never let it be said cheese is simple, quite the contrary: complex, surprising and interesting. Oh, and so very tasty.

Kris Lloyd is Woodside Cheese Wrights Head Cheesemaker 
woodsidecheese.com.au