What it takes: cheesemaking

Categories: Behind the stalls, Expert guidance

Bill Oglethorpe of Kappacasein on the work involved in producing his range of washed-rind cheeses

Interview: Clare Finney

Though he learnt his craft in the wildflower-strewn meadows of the Swiss Alps, today Bill Oglethorpe makes his cheese not in a remote alpage, but under a railway arch in Bermondsey. His milk comes fresh each morning from the beautiful Commonwork Farm in Kent. From this, every few weeks, he will make a new starter.

“If you are making a very specific cheese, you might want to buy in a starter tailored to do that, but the cheeses I am making seem to work well with the naturally occurring bacteria in the milk,” he explains. “Personally, I think you get more diversity that way. Raw milk offers a range of textures and flavours, but the starter cultures you can purchase are usually very strong, and there are not many varieties. My approach can be intimidating, because the Food Standards Agency guidelines are so strict, but it is more natural, cheaper, simpler and, if you think about gut flora, perhaps healthier.”

What is the role of the starter culture?
Back in the day, there were no starter cultures. Cheese was made by simply leaving the milk to sour. Now, people think you can’t make cheese without a starter—which is certainly true if using pasteurised milk. Pasteurisation brings the overall bacteria count down, good and bad, so it won’t ferment by itself. If you’re using raw milk, a starter helps boost the already naturally occurring micro-organisms. There are lactic bacteria—the bacteria needed to convert lactose into lactic acid—in raw milk anyway, but the starter makes sure they grow, that they outnumber any bad cultures that might be in the milk, and kickstarts the process of lactic fermentation.

How do you make a starter?
By incubating fresh raw milk overnight. I’ll send it off for testing, and if I come across some really good lacto-fermentation, I’ll use that batch to make a starter. Then the process is a closed loop. We put 50ml into a litre of fresh milk, leave it for eight hours, take 50ml out and put it in the fridge. The following week we take that 50ml, put it in a litre of fresh milk for eight hours, take 50ml out, put it in the fridge and so on.

How do you know it’s safe?
Starters are surprisingly resilient: it was making sourdough that taught me that initially. Of course, it’s easier to experiment with bread than with cheese, because it is less risky, but it is a similar process in that you keep the starter going over time. Like many things in life, you build confidence through experience and getting consistent results.

I have the starter and milk tested regularly, and there has never been a problem. As well as sending it off for tests, I keep track of the milk myself. It’s something I saw in Switzerland: if they buy milk in, they incubate some without any starter in it to get an indication of the state of the milk. If it’s not up to standard, they’ll get an early warning.

Also, the type of cheeses I make—Bermondsey Hard Pressed and raclette—are intrinsically safe, because they are hard and dry. It’s with soft and blue cheeses that you can have more risk of contamination.

What’s the reasoning behind washing your cheeses with salt water?
I went to a conference on the science of cheese a couple of years ago, over in America. There, a farm called Jasper Hill is working with scientists who specialise in sequencing and identifying communities of bacteria. They showed that the growth that occurs on the rind of a washed cheese consists mainly of sea bacteria, which are encouraged to grow on the cheese by the effect on its pH of washing with brine. It is washing the cheese that makes it go pink: other unwashed aged cheeses, like cheddar or Caerphilly, have a green-grey-white rind, reflecting a different ecosystem of bacteria. Stinky French washed-rind cheeses like reblochon go more soft and sticky because the cheese is smaller and more moist, so the bacteria grow a lot faster.

How often do you wash them?
The more often the better, particularly when they are young because if you don’t wash enough in the beginning, other cultures can develop that are hard to get rid of later. I have come to realise that it’s worth washing twice a week at first, then going down to once a week after a month or so. We do this for 12 to 18 months. In order to help the younger cheeses, we wash them in the same water we have used to wash the slightly older cheeses, which have a more established culture.

Do you think naturally occurring bacteria in the atmosphere affect the tastes of cheese in ways we don’t even realise yet?
Each farm seems to have its own flavour and smell—at least, each small-scale farm. I don’t know if it’s the feed, the grass, the buildings—there are a multitude of choices you have to make—but it seems to be imbued in everything.

I think even cheesemakers who buy starters aren’t aware of the significance and role of naturally occurring bacteria. There is quite a lot of lovely variation in Montgomery cheddar, for example, whether you attribute that to the starter or to the batch of raw milk. What the cows eat seems to make a difference. In winter, when the cows are on silage, there can be problems with the flavour and texture of their milk. These days, we try to make all our hard cheeses in summer to age over winter, and in summer concentrate on our fresher products like the ricotta, yoghurt and Bermondsey Frier.