Topping anaerobic ferments with oils.

So, do you? There is a nicely executed series called Saurkraut Survivor which found an olive oil topped kraut to be among the top choices on how to make and store kraut.
Botulism is the usual objection, but there is no water or veg in the oil, only in the brine.
The brine itself is inhospitable to botulism, or we would be in trouble, oil or no.
One source say the organisms that produce botulism toxins need protein as well as water and warmth.
4.6 is the usual PH cut off for Botulism but one study says it grow in solutions that acidic. They did use a protein rich substrate, so...
Anyway, if olive oil is questionable, how about coconut oil?
It has a huge amount of free fatty acids, being made largely of Lauric acid. No PH measurement is possible since it is an oil.
Known for its antibacterial properties, it should be liquid at fermenting tempatures, solid at storage tempatures. I have seen one person report using it to good effect.

So , just wondering what y'all thought about using oils to cap ferments, coconut in particular.

Indian pickles use oil. One person who gave me detailed instructions on how to make her traditional carrot pickles did specify keeping a thick layer of oil, like one full inch, on top, to make sure it's airtight; She said it stays good for months at room temperature in Bombay, and she's been making it annually for 30 years. The Indian and Ladakhi pickles that I have made only have a thin layer of oil coating the vegetables like a dressing, but after fermentation they have to be kept cool like kimchi or sauerkraut, or else they go oversour. Both of these, like all North Indian pickles, are made with "mustard oil" (which I recently learned is probably rapeseed oil). In South India they mostly use sesame oil for pickles; they use coconut oil for cooking but I don't know if they use it for pickles.

If botulism can grow in acid environments that would overthrow everything we've been following about canning and pickling. I thought it can survive in an acid environment but it will remain dormant and not produce the toxin. Everything I've read and heard about pickling is that lactic acid fermentation makes the environment too acid for botulism to grow and produce the toxin, so we're all set.

So yes, I think a thick layer of oil will protect anaerobic conditions below it, and as long as what's below is going to ferment and you haven't tried to sterilize it, it will go acidic enough to be fine.

Thank you, very informative!
I often wonder what I miss out on by only knowing English...
Sesame sounds wonderful as a ferment topper, and your friends experience suggests one should get good long term storage in moderate climes.
I like the idea of excluding mold without needing air locks, post collapse.
Acorn oil anyone?

I really like this idea and have a couple things I'm wondering about. Would you pull the finished fermented kraut or whatever through the oil to remove some to eat or would you need to pour some of the oil off each time and replace? and would the oil hold the fermented things under it or would there still have to be some kind of barrier to hold everything down in the brine during fermentation? I have some kraut ready now that I might experiment with.

Indians telling about pickle always insist you have to use only a perfectly clean and DRY spoon to pull it out. My friend went so far as to say that in her house only she is allowed to remove pickle to a serving dish because she doesn't trust her kids or husband to keep the spoon dry.

She said if the level of oil goes below about an inch thick you can just add more.

oil floats above water and it also stays above the vegetables. Indian pickles are oily and very spicy. Recipes I've found in books or online tend to semi dry the vegetables first either by frying or drying.