[godelski]

Interestingly enough I did a deep dive on mushrooms and vitamin D about a month ago. You can easily find a lot of papers that demonstrate sunlight and vitamin D with mushrooms, so don't take the unofficial training as a knock (we should always be skeptical, but verification exists).

It's all about UV light. Some producers are now using UV to help increase the vitamin D of their mushrooms (along with killing bacteria) but they can also quickly lose it when in the fridge. So just set them out on the windowsill 15-90 minutes before you use them. The more the better. Surprisingly this even works for dried mushrooms, so just build the habit. If you don't, you basically shouldn't expect to be getting meaningful amounts of vitamin D from your mushrooms. The effects are this large.

In addition to this, make sure when you cook, that you start your mushrooms dry. This isn't a vitamin D thing, but most people cook their mushrooms wrong. They have a lot of water in them to begin with. Start dry, then when you add things they will soak up surrounding flavors and have a better texture (people's main concern), being more meaty than spongy/slimy.

[r00fus]

> In addition to this, make sure when you cook, that you start your mushrooms dry. This isn't a vitamin D thing, but most people cook their mushrooms wrong. They have a lot of water in them to begin with. Start dry, then when you add things they will soak up surrounding flavors and have a better texture (people's main concern), being more meaty than spongy/slimy.

This is how they do it in Chinese soups, but honestly I haven't personally seen other cultures use dried mushrooms.

[InitialLastName]

I suspect they mean "dry" as in "not damp from washing" not "dry" as in "dehydrated". Lots of people wash their mushrooms, which can lead to them cooking down soggy.

[godelski]

You're closer, but I specifically mean to take your fresh mushrooms and throw them into the skillet without any oil (or water). Using dehydrated mushrooms in soups is kinda a shortcut to this.

Though the above comment mentioned Chinese soups and we should recognize that they often use wood ear, which is a different class of mushrooms than most westerners are used to. Wood ear are jellies whereas most western cuisine uses mushrooms with caps and stems (cremini, chanterelles, morels). Still, in general I recommend dry sauteing mushrooms before adding them to the rest of your dish.

More detailed cooking explanation:

Mushrooms are mostly water and air (i.e. a sponge), which is why the traditional French cooking methods tell you to not wash your mushrooms but to clean dry. So recognizing that these are mostly water, really we want to draw the water out, heat (break down cell walls), and then rehydrate with something more flavorful. Most people fuck up on the first step, by using too high of a heat or using something that the mushroom absorbs (oil or water). You start low heat, then the mushrooms release their water, you then bring the heat up to evaporate the water (now cooking the mushrooms). After that, your options change and you need to decide if you want to just brown the mushrooms with oil and seasoning or add them to a sauce or soup. The former will maintain a lot of mushroom flavor but also that nice fat and seasoning. The latter is going to absorb your sauce and add texture and add umami flavor. Either way, you generally reduce the heat here. But I cannot stress enough how mushrooms are sponges and you have to cook under this paradigm. It's like the difference between cooking french toast with bread straight from the loaf or using bread that has been left overnight (or a bit stale). Though maybe this is a bad comparison because a lot of people don't use stale bread for french toast either, despite that being a major part of its history.

[UberFly]

I usually look at all the gunk on the mushrooms, and knowing they're grown in a chicken poop mixture, wash them anyway. Probably not better than a good wipe but I can't help myself.

[tstrimple]

Rinsing them is absolutely fine. The "food science" recommendation around cooking mushrooms has changed in the last few years. Many cooks are seeing good results by starting to sautee the mushrooms in water and only cooking with oil once the water has boiled off. This enables the air pockets to collapse and for a lot of the moisture to evaporate so you end up needing significantly less fats. I've switched to this method myself, and I've been very happy with the results.

https://www.americastestkitchen.com/cooksillustrated/article...

https://www.youtube.com/watch?v=OPJmJdStvwI

[Mistletoe]

This is a really cool idea, thanks for sharing it. I can’t wait to try it.

[zhengyi13]

Might well depend on the species as to which conditions are most favorable, but AIUI most of your farmed mushrooms are grown on other-than-poop substrates: grain, straw, wood and wood pellets, coffee grounds, shredded coconut husk.

Probably still a good idea to clean them off, though: none of those other things are particularly tasty :)

[godelski]

> knowing they're grown in a chicken poop

Most mushrooms you eat aren't coprophilous fungi. You're probably thinking of some variants of magic mushrooms (not all magic mushrooms grow on dung).

The mushrooms you're eating grow from the dirt. If you're into mushrooms, you'll probably also have mushrooms that grow on trees. But unless you're looking to trip, you're not getting poop shrooms.

[chris1993]

Commercially grown mushrooms are usually grown on a pasteurised medium so anything attached to the mushroom should be free of pathogens.

[contingencies]

Many Southeast Asian cultures dry mushrooms. I would suppose, purely based upon the scarcity of winter foods, that northern cultures (Korea through Siberia, the Altai, Central Asia, Russia and Nordics) would also.

[tptacek]

Is this a problem a lot of people have, the slimy mushroom thing? I don't do anything special or careful at all with mushrooms; I rinse them off, maybe halfheatedly salad-spin them, chop them up and put them in a hot pan with some fat. I've never had a slimy one.

[quicklime]

I used to carefully clean my mushrooms with a brush to keep them dry so they wouldn’t end up slimy. But someone told me that was a myth and I decided to try just quickly rinsing them instead. Never resulted in slimy mushrooms, and I was shocked at how much crap ended up in the rinse water.

[tptacek]

My current belief is that there's nothing you can do to a mushroom that a hot pan won't fix.

[beambot]

Parboiling is often a critical step for certain mushroom species to remove toxins. But that's probably only relevant if you're foraging outside your local grocer.

[godelski]

Tbh, it mostly comes from people using too much oil. I have a longer description of my preferred cooking method above, though I should add that I still love them when cooked the normal way.

[emrah]

Glass blocks UV radiation I believe, so you'll need to lay them outside to get sunlight directly

[godelski]

Glass blocks UV-B and UV-C, but not UV-A (unless you have a film). Many mushrooms can be enriched with UV-A, but UV-B is best. So yes, I agree, better to place outside in direct sun (or window open). But building the habit is the harder part for people tbh.

[contingencies]

Also transparent polymers will generally break down with prolonged UV exposure.

Alternatively to leaving them exposed outdoors, you can use quartz.

[chownie]

Glass doesn't block UV A so that might not be the case, don't know in particular which type of UV rays the mushrooms need to produce vitamin D however.