Sweet Dreams Are Made Of Cheese

When milk and microbes come together, there’s no doubt something wonderful happens. We asked a food scientist how a choreography of chemistry, biology and psychology make cheese the ultimate food

- Stuart Farrimond

Who would have thought that a congealed lump of curdled milk could be so delicious? For 7,000 years, cheese has titillated the taste buds of humanity. In almost every corner of the world, animal milk has been used to create the stuff, culminating in over 1,700 distinct varieties today: creamy Brie; buttery Gouda; crumbly Parmesan; stringy mozzarella; sharp Cheddar; holey Swiss; mild paneer; smoky Bavarian Emmentaler… the list goes on and on. The staggering variety of cheeses is testimony to the creativity of cheesemakers throughout the ages, but their ingenuity plays second fiddle to the real stars of the show: the microbes. The several-hundred-strong ensemble cast of bacteria, fungi and yeasts bring life to a bland, salty lump of off-white curd. By digesting, or ‘fermenting’, the fats, proteins and milk sugars, they spew forth a complex selection of flavourful – sometimes smelly – molecules. Never has second-hand food tasted so good! But what is it that makes cheese so devilishly moreish?

The milky way

All cheeses start their lives as milk. Most animal milks can be used, including cow, buffalo, goat, sheep and even camel. The milk is first warmed to a temperature perfect for milk-loving microbes to flourish. Next, acid or rennet is added, possibly alongside some ‘starter’ bacteria. This causes the milk proteins and fats to coagulate together into ugly white clumps, ‘curdling’ the milk. These fat-laden ‘curds’ then float to the surface of the milky liquid, the ‘whey’. The curds can then be drained, removed and chopped into chunks, according to the type of cheese being made – walnut-sized blobs for soft cheeses, and small grains for hard cheeses.