Soaking Mushrooms

[Chris Amirault]

Thanks to a recent trip to Your Dekalb Farmers Market, I came into a lot of dried porcini mushrooms. The first dish I made with them was on a Saturday night, and I soaked the mushrooms for a couple of hours before straining the liquid and using the mushrooms. Somehow they seemed less fragrant than I had expected, which I decided must be a result of inferior product.

However, the next time I used them I was following a recipe in Molly Stevens's All About Braising, in which she made a point of saying not to start soaking the mushrooms until no more than 30 minutes prior to use. It seems to have made a huge difference: the mushrooms had the wonderful, familiar heady fragrance that you pay big bucks to get from porcini.

My method was the same: very hot tap water to cover in a pyrex measuring cup; I put a small bowl over the top to push the mushrooms below the water level. The mushrooms were the same.

So what gives? Why the significant difference? I ask since Stevens seemed to nail the timing on the head -- but for the life of me I can't figure out why.

[Shalmanese]

Seems simple enough to me. THe mushroom flavour is being leached into the soaking liquid. If you use both in the same dish, you should capture all of the flavour although it might be more volatile in the liquid which might lead to less flavour.

[Fat Guy]

When you reconstitute dried mushrooms, you're basically creating two things: reconstituted mushrooms, and mushroom-infused liquid. The longer you soak the mushrooms, the more flavorful the liquid becomes and the less flavorful the mushrooms become. Almost all directions I've seen for reconstituting specify 20-30 minutes (pour boiling water over mushrooms, let soak while the water cools), except for mushroom broth directions which can say to soak overnight.

This all raises some additional questions:

- In a braised dish, or any dish where there's liquid, where you add both the mushrooms and the liquid, does soaking time matter very much?

- Indeed, if you're braising a dish for several hours why bother soaking the mushrooms at all? Why not just add them dry to the braise?

- There must be a point in the osmosis process when the flavor stops coming out of the mushrooms. I wonder, if you soak mushrooms in mushroom liquid, will you be able to reverse the osmosis and put more flavor into the mushrooms?

[jayt90]

A slow braise may leave the stems too tough, but many cooks discard them or throw into the stock pot antway.

[Hiroyuki]

The best way to reconstitute dried shiitake mushrooms is to soak them in cold water and put them in the fridge for up to 24 hours. This allows the enzyme on the outside of the mushrooms to act on ribonucleic acid to produce a "umami" component called guanylic acid.

I don't know whether this applies to porcini, though.

[beccaboo]

- Indeed, if you're braising a dish for several hours why bother soaking the mushrooms at all? Why not just add them dry to the braise?

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Whenever I soak mushrooms I end up with gritty liquid, which I strain before adding it to my dish. If you added the dried mushroom directly, you'd have no chance to get rid of the grit!

[Fat Guy]

Maybe that varies by mushroom type. I've not seen that happen much, but the ones I've used were probably something bulk, commercial and grown rather than real wild mushrooms with earth on them. Also, based on some package directions I read ages ago, I always rinse them first -- not that I do any of this very often; I somehow have never incorporated dried mushrooms into my cooking routine so only use them when they're very specifically called for.

[Chris Amirault]

I'm wondering specifically about porcini, whose aroma is crucial to most dishes. I've never had this problem with shiitake.

Thanks for the explanations, but I'm not sure that they get at the crux of the matter for me. I just removed meat from sinew on the short ribs in question, and the porcini aroma was remarkably strong considering it had been in the fridge for a few days after both an initial braise and a warm up for service a day later. I think Steven's question is what I'm curious about:

- In a braised dish, or any dish where there's liquid, where you add both the mushrooms and the liquid, does soaking time matter very much?

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I didn't make it clear before that I used the mushroom liquid in both dishes.

[Wolfert]

In Ma cuisine des champignons by Régis Marcon, the chef soaks dried cepes up to 24 hours without harm. He suggests adding a pinch of salt or sugar to the soaking water.

After cooking from his book, I discovered that when preparing a quick saute of fresh and dried mushrooms, the 30 minute soak is ideal, but for long simmered dishes such as ragouts and daubes, the long soak produces a stronger flavored addition to the sauce.