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Comment by xkapastel | Hacker News Reader

This article was frustrating because it danced around my main issue: I'd be worried about getting sick. There was maybe one sentence that acknowledged this:

> I think the fear of contamination and making one’s self sick is the biggest barrier.

This is a big deal, but the article makes light of it, doesn't even give it its own section, and instead presents a bunch of flowery prose about making death a part of life.

As one example of this, how are you supposed to protect these fermented foods from pests? I get the sense you're supposed to leave them out, uncovered, but that assumes you live in an area that allows you to do that.

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I think by "leave them out", you meant to say "leave them outdoors". That is not the case. FTA:

"Lewin learned to keep his projects out in the open: ‘One thing I do is I leave all of my fermentation projects in plain sight. I see them every time I go in the kitchen."

So the article is saying they keep their ferments indoors, which is what other posters say they do. I think you might be worried that the ferments are left out of the fridge? Well, they mostly have to be because fermentation almost shuts down at temperatures that cool.

Fermentation is exceptionally safe. The lactic acid created in the fermentation process plus the salt makes for a badass combination against bad bugs. Sandor Katz wrote in the Art of Fermentation that if it tastes bad, throw it out. Even if a bit of mold grows on top, you can pick it off and let the fermentation continue (only if the mold grows for too long and it gets really rooted into the ferment should you throw it out, and that is just because it would taste terrible). If you are worried about botulism (a nasty toxin that has no taste), you shouldn't be:

https://www.masontops.com/pages/botulism-and-fermenting-shou...

I'm far more worried about getting sick from e. coli in romaine lettuce bought fresh from the grocery store than from any of the ferments I make.

re the part about removing mold: does that only hold for fermentation?

I somewhat recall having seen an interview of a doctor talking about mold (in e.g. jams) and stating that you should be generous with the part removed because mold has roots that go far deeper that what you actually see. Furthermore, he mentioned it (or byproducts, I don't recall) being carcinogenic, i.e. definitely not just bad taste.

Here, we do all fermentations indoors.

Leaven is happy in a small jar, just let the cover on top, unscrewed to prevent pressure buildup. When stored in the fridge, you can screw the cover, only not too tightly.

Vegetable pickles are happy in a mason jar (or Le Parfait jar, in France), just open carefully a few times at the start of the fermentation to let the gas out.

We ferment kefir and kombucha for several days (kefir) or weeks (kombucha) at ambient temperature in a large (~2 litres) jar, covered in gauze to stop airborne contamination and flies.

I imagine fermenting things outdoors would be a bit more tricky, mainly because you need stop things bigger and smarter than fruit flies.

So you need a bit of knowledge about what keeps you from getting sick, but actually preventing the sickness is very, very easy. In fermentation, there are several ways of doing this, but salinity and acidity are the most important factors, and those are built into your fermentation recipes. Kahm yeast can be scooped off the top when you see it form, and while molds can (but don't always) ruin a ferment, they're uncommon if you're maintaining proper salinity, using fermentation weights, and starting with very clean equipment.

You don't leave your ferments uncovered, and while you can do fermentation in ways that you'd need to worry about pests, cheap fermentation equipment that will make the question irrelevant is easily available.

> As one example of this, how are you supposed to protect these fermented foods from pests? I get the sense you're supposed to leave them out, uncovered, but that assumes you live in an area that allows you to do that.

Typically the recommendation is doing ferments indoors with a cloth on top to protect from pests. I use jars with one-way valves that allows gas out but not in. Vegetables are covered in natural microbes and you don't have to keep them uncovered or out. I do my ferments in a city apartment with no issues. :)

I'm no expert, but here are some details.

If microorganisms gather on the surface of your fermented food in large enough numbers that you can see them, you have two choices: (A) try to save it, or (B) throw it out. If you don't see any, then there hasn't been an environment suitable for them to grow, meaning they aren't there in nearly enough numbers to get you sick.

As far as pests, you're generally expected to cover your fermentation somehow. Something like a tea towel or cheese cloth can work, or even a pot lid, probably depending on the fermentation in question. Just follow the instructions and it should turn out okay, but I don't see any reason to keep it uncovered.

I've made a sourdough starter before, and there was some initial activity before fermentation appeared to stop, and then after a few days it started again and settled into a steady state with consistent activity after feeding. I don't know what caused the initial activity, but one candidate is Clostridium perfringens, which is potentially fatal if eaten raw. Clostridium perfringens is actually used as a raising agent in "salt-rising bread", which is generally considered safe if thoroughly cooked, but what if I was fermenting something intended to be eaten raw, like sauerkraut sometimes is? I expect harmless lactic acid bacteria will eventually kill the competing microbes, but they won't necessarily be the first to colonize the food.

https://en.wikipedia.org/wiki/Salt-rising_bread

I've had my starter going for many years. What you saw was extremely unlikely to be Clostridium perfringens. The very article you linked says "salt-rising bread starter requires a shorter incubation period of 6–16 hours and a higher incubation temperature, ranging from 38–45 °C". I've made salt-rising bread before a number of times, and I use my immersion circulator to maintain the temperatures that encourage its growth.

I think salt rising bread is delicious, though my wife is a bit put off by the smell. And from the fact that she wrote up a bunch of necropsy reports on animals where one of the factors that led to their demise was Clostridium perfringens. But, as Howard McGee (author of the amazing On Food And Cooking) writes, there is a "lack of any known cases of the bread causing illness". His article on the topic is pure awesome.

https://www.popsci.com/article/science/clostridium-it-can-ki...

My wife was making pickled eggs yesterday. I asked her "How much salt are you using?" "Oh... I forgot the salt. How much should I use?" I told her to look at the recipe. She said she wasn't using a recipe and was just going to wing it. I told her I didn't want to die. :-)

This is the real danger. Although we weren't fermenting the eggs (vinegar recipe), no matter what you are doing, you need to be very careful about the amount of salt/acid you are using. Additionally you need to be very careful about sanitisation (For our pickled eggs, I showed my wife how to sanitise the jars using iodophor). Once you have that sorted out, there really isn't anything that can go wrong.

Basically follow the recipe to the letter. Read it ahead of time a few times so that you know what you are doing. Double check that you did every step and that you measured the amounts correctly. Avoid any recipe that has a "Oh it's natural, you don't have to measure anything" approach and you will be fine.

As for pests, I suppose some things may be fermented uncovered, but I've never done that. For fermented pickles, I just loosely cover the jar. The biggest pests you are likely to encounter is fruit flies -- but they really only go for yeast fermented products (they eat yeast). For things like that (i.e. making beer, etc) you want to use a covered vessel with a fermentation lock.

I've never had problems with lactic fermented things including lactic pickles, sauerkaut and even cheese (though my cheese is in the fridge most of the time and when it is air drying, I've got a cheese cloth over it). We've got every sort of beast you can imagine here (rural Japan), including 2 inch long cockroaches that can fly, venemous foot long centipedes, skinks, hunter spiders, etc (the skinks and spiders eat the cockroaches, thankfully). In my old falling down shack that I used to live in, I even had a rat that would eat all my chocolate and cold medicine, but leave the yummy, yummy grain alone (go figure).

Basically, you are right to be cautious, but you have no need to worry if you are cautious.

do that indoors and just put a rubber glove on top of a jar [0] if you are concerned about contamination or smells

[0] https://www.google.com/search?q=fermentation+rubber+glove&so...

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