More on the subject of Penicilium candidum, aka, white mould

Penicilium candidum is a turotrophic (cheese-eating) fungus that is responsible for the particular nature of cheeses like Camembert and Brie.  That beautiful soft white coat you see on the rind of these surface ripened cheeses is the manifestation of the Penicilium fungus that consumes them.

For cheesemakers to ripen a fresh round of cheese into a Camembert or Brie, they must add fungal spores of this species into the milk at the beginning of the cheesemaking process.  The spores do not have an effect on the cheese during the early stages of its development.  It’s only as the cheese begins to age that signs of Penicilium candidum begin to show.

Within an ageing Camembert cheese these fungal spores germinate and start to form a branching network of root-like filaments known as mycelium.  As the mycelium makes its way through the fresh cheese, it feeds upon it, imparting changes that ultimately ripen the cheese into a camembert: the fungus produces enzymes that soften the flesh of the cheese as they metabolize its proteins; it produces interestingly flavoured mycotoxins that protect the cheese from the growth of other fungal cultures; and upon the surface of the cheese, where the fungus is exposed to the air, it begins to form microscopic spore producing bodies that appear to the eye as a beautiful white coat.

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For years I searched for a wild source of Penicilium candidum fungus.  I skimmed the white coats off of mature Camemberts – but ended up with Penicilium roqueforti contamination.  I coveted mouldy peaches, introducing their white fungal infections into cheeses I had hoped to ripen into Camemberts, but the fungus never grew true.    I had nearly given up, when I found the answer in my milk:  kefir.

The Latin name Penicilium candidum reflects the whiteness of the fungus that ripens Camembert cheeses.  There happens to be another white fungus that influences cheeses in a nearly identical way, one that is found in traditional French cheeses.  This fungus is Geotrichum candidum.  And you’ll never guess where it’s found – in kefir grains!

Kefir may just be the perfect cheesemaking starter culture: it’s easy to cultivate without risk of contamination; it contains a vast diversity of bacterial cultures that are useful in the production of every type of cheese; this same diversity of cultures helps to provide an incredible diversity of flavours in these cheeses; and finally, kefir is an excellent source of a beautiful fungus that can be used to ripen Camembert and Brie cheeses – Geotrichum candidum.

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Geotrichum candidum is an ideal replacement for Penicilium candidum.

When introduced as a spore, the fungus consumes the cheese as it ages and produces similar results as Penicilium candidum:  the cheeses soften up in a similar way, they develop similar flavours, and they grow an even more beautiful white coat.  The rinds of Geotrichum-influenced cheeses have delicately wrinkled texture that adds another layer of beauty to the cheeses.

Geotrichum fungus is found naturally in raw milk.   Cheeses made with raw milk will grow a Geotrichum-influenced rind without intervention.  Cheeses made with pasteurized milk, however, need to have the Geotrichum fungus added. Most cheesemakers add laboratory-raised freeze-dried spores to introduce this fungus, but this is entirely unnecessary if kefir culture is used to start the cheeses.  Even when using raw milk, the addition of kefir culture can help to reassure that the fungal culture that dominates the cheese is indeed Geotrichum.

All one needs to do to keep a culture of Camembert fungus is to keep kefir culture.   If you use the kefir as a starter culture, you can be certain that the cheeses you make, if handled well, will grow a healthy Geotrichum culture.

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So, to begin the Camembert making process, warm up your milk to 90F and toss in about one teaspoon of kefir grains for every gallon of milk. In so doing, you’ll have added both the bacterial starter culture, as well as the fungal ripening culture. Just don’t forget to skim your kefir grains off the top of the curd once it has formed after renneting…The grains can be used for ages, so long as they are well taken care of.

Something to keep in mind; commercially prepared, freeze-dried ‘kefir’ cultures are not actually kefir.  They are not produced with kefir grains, and they do not contain the diversity of cultures that true kefir does.  I do not suggest using them as a starter culture, because they do not contain the Geotrichum fungal culture.

If you’re interested in keeping your own Camembert fungus at home and would like some kefir grains, I offer kefir grains for sale on my kefir website, gotkefir.wordpress.com