That acetone flavor is ethyl acetate, which can come from some wild yeast, stressed domesticated yeast, and some bacteria. Commercial yeast doesn't eat lactose tough, so I'd assume a different micro organism. Have you improved sanitation in your process since?
> Have you improved sanitation in your process since?
Yes, very much indeed. Although the wild yeasts came from the starter culture I used at the time: milk kefir. Long story :)
Kefir cultures include lactose fermenting yeasts, in particular Cluyveromyces marxianus. It could be the culprit. Anyway something in my culture was producing alcohol because I could see bubbles in bottles of whey and I even had a small explosion once. Ahhh, the joys of washing goat-smelling whey from the walls of the kitchen...
Edit: In my experience almost everyone in home cheesemaking says they have impecable sanitation and that can't be the source of problems like early blowing etc. I like to buck the trend and admit that I try my best, but it's never possible to have 100% sanitation in a home kitchen and even less so when making cheese which is a protracted process with many opportunities for contamination. At least, since I've switched to using lyophillised cultures I've had only one cheese exhibit late blowing. And most of my hard cheeses have squeaky clean natural rinds without a spot of yeasts or moulds. That's probably a good sign.
Interesting, k. marxianus could be producing fusel alcohols which have sort fo a nail polish remover flavor/smell.
> because I could see bubbles in bottles of whey and I even had a small explosion once. Ahhh, the joys of washing goat-smelling whey from the walls of the kitchen...
bottle bombs are scary. I switched all of my beer making to kegging, because of how much of a hassle bottles can be.
Milk seems like a great host for lots of organisms, I don't envy the work cheese makers have to put it to get the right kinds of microorganisms established first. Beer is easy, b/c s. cerevisiae out competes everything in a high glucose environment.
Although is seems like kefir cultures contain s. cerevisiae sometimes. There must be some yeast/bacteria that converts lactose to another sugar in there as well.
> bottle bombs are scary. I switched all of my beer making to kegging, because of how much of a hassle bottles can be.
I was trying to make whey mead a.k.a. "blaand" as I imagine a cheesemaker would do it using cultures one would expect to find in milk or dairy like C. marxianus, rather than how a brewer would do it with C. cerevisiae. I got... something, not particularly pleasant to drink.
> Milk seems like a great host for lots of organisms, I don't envy the work cheese makers have to put it to get the right kinds of microorganisms established first. Beer is easy, b/c s. cerevisiae out competes everything in a high glucose environment.
Yes, you gotta be very careful with milk. There's a bit of a fashion in home cheesemaking for raw milk (inherited from artisanal cheesemaking, which in turn inherited it from European cheesemaking traditions). But I always pasteurise. If I had a proper dairy plant and could easily test the milk I use for pathogens and spoilage orgranisms, then OK, but I'm making cheese in a kitchen! Everything I can do to make the process safer and more predictable in outcome is worth it.
> Although is seems like kefir cultures contain s. cerevisiae sometimes. There must be some yeast/bacteria that converts lactose to another sugar in there as well.
Kefir is a wild culture so there's all sorts of organisms in there. I'm not sure anyone really knows them all. I've read a few papers that analyse the bacteria and yeasts in kefir "grains" from different parts of the world. It's a very varied bunch. It basically has the kind of variety of organisms that you can expect in raw milk, plus a whole bunch of yeasts and that makes it very hard to control as a cheesemaking culture. Part of why I gave up on using it as a starter. It's great for making yogurt though because the higher heat needed in yogurt making effectively filters out mesophilic organisms and leaves only the thermophiles used to make yogurt.
