Craft and science: the cheesemakers

Achieving the complex flavours that give brands their unique taste is a delicately balanced blend of tradition, craft and science

Thu, Mar 20, 2014, 01:00

Guests at Irish embassies on St Patrick’s Day didn’t only pass around the shamrock, there was something else on the menu. They were invited to tuck into a range of Irish cheeses, Durrus, Coolea, Cashel Blue and Knockanore smoked cheddar.

For them it was all about the taste, but in reality achieving the complex cheese flavours not only showcased Irish food, it showed how cheesemaking is a blend of tradition, craft and science.

A seemingly minor difference in milk can have a big impact on cheese, says Dr Michael Tunick, a US chemist whose book The Science of Cheese comes out next month. “Anything the cow eats gets carried over,” he says. “Hundreds of flavour compounds have been identified in cheese.”

That Irish cows feed on pasture matters. Conditions during processing are even more important – they determine which microbes thrive.

Dubbed the “wine of food”, cheese is fermented by microorganisms deliberately added after milk gels due to rennet, an enzyme originally obtained from calves’ stomachs. Whey is drained off and the curds are treated to encourage or discourage the growth of bacteria, fungi and yeast, giving us the 2,000 cheese varieties.

“It is probably one of the most complex industrial fermentations because you cannot make cheese from sterilised milk,” says Prof Paul McSweeney, cheese scientist at University College Cork. “In most industrial processes you kill off the microbes by sterilising. You can’t do that for cheese and that makes the microbiology more interesting.”

Cheese dates back to at least the sixth millennium BC and was a way of preserving the nutritious value of milk. But cheese is also incredibly dynamic involving thousands of microorganisms and hundreds of flavour compounds, which develop with age. Understanding microbiology helps with consistency.

More than 1,400 scientific papers mention cheddar in their title, yet it is still impossible to guarantee how a batch will taste or know if it will develop into tangy mature cheddar. Understanding the microbiology helps with consistency though.

Blues and cheddar
Sheridan’s Cheesemongers supplied the four farmhouse cheeses as their cheeses of the month. The presence of microorganisms is obvious in blue cheeses such as Stilton.

While tasting Cashel blue in Sheridan’s in Dublin, manager John Leverrier says they let the wheels mature for 14 weeks. Dormant spores of the blue mould grow when the cheese is skewered and oxygen enters; the mould, Penicillium roqueforti , traditionally came from stale rye bread and was sprinkled onto Roquefort cheese.

Roquefort is distinctively French, but no native cheese survived our turbulent history. “Old Irish literature mentioned names of certain cheese and whether they were hard or soft, but no details of how they were made,” McSweeney explains.

Cheddar is an internally bacterially ripened cheese, meaning microbes don’t grow on its outside; instead it ripens inside, as enzymes break down fats and proteins, releasing flavour compounds. “What we think of as cheddar is the combined effect of a large number of compounds. Some are more important than others, such as sulphur-containing compounds like methanethiol,” says McSweeney.

After acid has developed, cheddar cheese curd is cut into small pieces, salt added and the curd pressed. “You wouldn’t recognise freshly-made cheddar,” says McSweeney. “It takes time for the flavour to develop and strong flavoured cheddar is older, though you can’t set out to make mature cheddar because there is still a bit of serendipity in how the cheese ripens.” Adding salt helps determine which bugs survive in a cheese.