“Curiosity led us to kefir”

Someone once said that cheesemakers are farmers of microbes, and the more cheese we make at Nettlebed Creamery, the more curious about them we become.

We make three different types of cheese: a soft, a semi-soft and a semi-hard. Each has its own particular relationship with bacteria. Bix and Highmoor, our soft cheeses, are made with mesophilic bacteria. A mesophile is a lover of moderate temperatures, between around 25-37°C. St Bartholomew, our semi- hard cheese, is made to a recipe where the curds are “scalded”. Mesophilic bacteria start the acidification and double in numbers every 30-40 minutes through the initial phases of the make before we heat the curds during the stirring phase to a punchy 45°C. Once the temperature gets in to the forties the mesophiles will slow their growth and then release flavour creating enzymes as the thermophiles take up the strain. Thermophiles, as the name suggest, are lovers of higher temperatures. That however is only the beginning of our quest to understand microbes.

From day one at the Nettlebed Creamery, we were dedicated to the raw milk cause, but the march of bovine tuberculosis across England meant that we had to concede defeat to M. Louis Pasteur. Having been in a low-risk area in south Oxfordshire we had a positive test result for TB. Determined not to say goodbye to all the microflora that our organic farm so liberally gave us, we have started to retro-cultivate the lactic acid bacteria that we know are abundant in our raw milk. Only a very small proportion of the organisms we find in our raw milk (that are likely strain-specific to our cows, our pasture, our soil and our fields) are even potential pathogens – the rest are flavour-generating friendly bacteria, yeast and moulds that are particular to our organic farm. After looking down the microscope at an ever-changing seasonal cycle of different microorganisms growing on agar plates in our lab our microbial milk quest inevitably led us to kefir.

Our head cheesemaker and microbe guru Patrick had been making kefir at home for years but getting it market ready was a new challenge. We wanted to offer an organic kefir which wasn’t mass produced but was of the highest quality and so we set about propagating kefir grains with our own milk and testing, tasting, testing, tasting. Kefir is one of the oldest forms of fermented milk you can find in Europe. It is believed to have originated in the Caucasus mountains millennia ago. The health benefits of kefir are not fully understood, however, what research has been done seems to indicate that a healthy population of microbes in the gut is associated with an optimally functioning immune system, reduced inflammation and allergies, reduced digestive problems, improved mental health and a plethora of other somatic and psychological benefits. As a Polish friend recently told me, it is also a great tonic for a hangover. Of all the fermented foods, probiotics and microbial supplements tested, kefir appears to be one of the very few that can actually deliver beneficial microbes that survive the journey to the gut where they prosper. It is possible that the low pH of kefir means that the beneficial microflora have evolved to withstand the acidic environment in the digestive tract.

We have found that since launching our own kefir there are very stark differences between what we bottle and what can be bought in a supermarket. For starters, the viscosity is quite different. Ours is thick and leaves “legs” down the side of a glass. The supermarket varieties that we have tried are smooth and leave no trails. They remind us of Yop, a liquid yoghurt that used be available in the 80s and 90s. But we are artisan cheesemakers and quite used to the differences between supermarket produce and what we do. Fortunately, we know that there are consumers out there who are discerning and also on a microbial quest.