Culturing Dairy - Is Metal Evil? page

[yodiewan]

On a lot of the recipes for culturing dairy (yogurt, creme fraiche, kefir, etc) they say to use a glass or ceramic container. Some even say to avoid metal utensils. Why? I've used a stainless steel bowl to culture heavy cream. It took a few days, but otherwise I think it came out fine. Anyone have the science behind this?

[yodiewan]

After a little more Googling, I think I might have found an answer:

Wild Fermentation :: Vegetable Fermentation Further Simplified

What kind of vessel should you use to hold your ferment? Avoid metal, as salt and the acids created by fermentation will corrode it.

Which begs another question: Do I need to worry about this with stainless steel? It's pretty corrosion-resistant right? I'm wondering this because I don't have a really big glass bowl that would be appropriate for culturing some cream that I have in the fridge.

[randallfloyd]

I'd say invest in a glass bowl just incase. I use a plastic sieve and spoon to strain kefir and a glass jar to ferment/ripen it. I don't know if the metal thing is true or false but the way I see it it's not worth taking the risk. I mean, the cost of a plastic seive was only £1 (and it'll probably last 30 years). Got to weigh up the risk vs. the price. In my case it was worth it because I make kefir every day - Might as well make sure I'm doing it properly.

[AndreaReina]

Silver is anti-microbial. Aluminum is definitely corroded by acid, as is iron. Stainless steel is more resistant, and if it's good quality will actually live up to its name. Gold would actually be the best bet since it's very chemically inert, but who has a gold fermentation crock these days?

[dontmesswithpdx]

I've been using stainless steel when making kefir for the past couple of years and have had no problems with that.

[Lewis]

After a little more Googling, I think I might have found an answer:

Wild Fermentation :: Vegetable Fermentation Further Simplified


Which begs another question: Do I need to worry about this with stainless steel? It's pretty corrosion-resistant right? I'm wondering this because I don't have a really big glass bowl that would be appropriate for culturing some cream that I have in the fridge.

Stainless steel can even be used to handle sulphuric acid, although it depends on the acid and the grade.

It's used quite widely in the food industry—fermentation vessels in wineries, tanks for orange juice, and so on. Orange juice has a ph of about 3 to 4, so it's fairly acidic.

I can't imagine it would be a problem. I should think they say to avoid "metal", because you just can't use random metal X, and they've no way of guaranteeing that the reader knows which utensil is made from which metal. Some reader would be bound to do it in an aluminium container.

[breadsauce]

Dom's kefir site says stainless steel is OK, so I've been using a stainless steel sieve and spoon for my kefir. And so far it seems OK.

I would have bought plastic - but I figured stainless steel is fine with my sourdough (no, I don't eat sourdough or any grains - but I still make it for guests / friends) and the bacteria in that would have died if they didn't like it. And why spend an extra £1 on a plastic sieve when that same £1 can buy me more herring roes??!!

[yodiewan]

Thanks for all the input guys and gals. I will continue using my huge stainless steel bowls to culture my cream. More butter here we come!