do multiple ferments in a household affect each other?

Hi Wardeh

I call our house the 'House of culture' as there is kefir, yoghurt, sourdough, ginger beer, vinegar, beer, cider.... all doing their stuff.

I'm just wondering how I'm going to find room for the new cheese cave I want to start!

Do you find that once you have these cultures in the house that it's better or worse for starting other cultures

Would love your book as I enjoy your blog! Thanks for making yourself available

I love that! Our is a house of culture, too!

You can have cross contamination. Once I had my sourdough starter going right next to a batch of cheddar and the cheddar didn't work. I learned my lesson on that one. But most of the time, I don't have issues with it.

What I now do when making cheese is add the culture when the milk goes in the pot, even before it is up to temperature. This protects it from cross-contamination (not 100% but I haven't had a problem since I started doing this). Here's a video I made on youtube about it.

http://www.youtube.com/watch?v=xlfshmxE9rw

I've read several places that people are concerned about cross-contamination from fermentation projects, but I've kept a lot of different processes going at the same time and nothing bad that is obviously attributable to that has ever happened. I wonder what specific circumstances must obtain before it's a real concern. And how far do microbes spread from one open crock, for instance?

We've never had that kind of difficulty, even with water kefir, milk kefir, kimchi, saur kraut, sourdough, mead, and beer all going at once, in the kitchen.

I adopt the same attitude to microbes as I do to seeds—the more the merrier. I have been known to intentionally cross-contaminate various cultures for the sake of genetic diversity and local adaptation.

In the past I've always agreed: I have so many ferments that are always going and never had any problem.
But recently I've had a few batches of yogurt come out with almost a yeasty sort of tang going on. I've used a few new starters and it keeps happening. The only thing I can think of is that those days when I'm making new batches, I'm making bread too. I suspect it is more the flour (in the air, maybe, bearing wild yeast) than the actual bread yeast I am making (or sourdough).