Washing mushrooms in flour water

[wordsmith]

Does anyone know what the science is behind washing mushrooms in water with flour? I took a culinary course and the instructor said it bleaches the mushrooms (if they’re white ones) and acts as an abrasive to remove dirt. Would something with a similar texture to flour (i.e. baking soda or baking powder) do the same thing, or is there something special about flour that makes this technique work?

 

The instructor wasn’t totally sure. She just said not to leave the mushrooms in the water too long because the acid in baking soda/powder could soften them. I tried looking for more info online but didn’t find much. From what I did read, it sounds like it's a technique that might be common in France.

 

Thanks for your help!

[gfweb]

Sounds weird. Many advocate not washing them at all. I rinse them gently.

 

Baking soda is alkaline, not acid. And plain old flour shouldn't have any baking soda in it anyway.

 

But alkaline will soften pectin, it can make onions and potatoes mushy.... though I don't know if mushrooms have any pectin in them.

[pastrygirl]

I'm skeptical, flour is pretty soft to the touch and doesn't seem like an effective abrasive.  Did you actually do this in the course?

[JoNorvelleWalker]

1 hour ago, gfweb said:

Sounds weird. Many advocate not washing them at all. I rinse them gently.

 

Baking soda is alkaline, not acid. And plain old flour shouldn't have any baking soda in it anyway.

 

But alkaline will soften pectin, it can make onions and potatoes mushy.... though I don't know if mushrooms have any pectin in them.

 

The structure of mushrooms comes from chitin, same as the exoskeleton of insects.  I doubt baking soda would break down chitin, but I can't say I have tried.

[liuzhou]

2 hours ago, gfweb said:

Many advocate not washing them at all.

 

Isn't that a hangover from the days when people insisted that mushrooms absorb the water they are washed in - a theory that has long since been debunked?

 

2 hours ago, gfweb said:

Baking soda is alkaline, not acid.

 

True, but baking powder is mildly acidic.

 

That said, this sounds like a nonsensical old wives' tale. And a complete waste of time, flour and baking ingredients. You can buy special mushroom brushes if you want to waste more money.

 

Just wash them in water like any other vegetable.

 

Edited November 5, 2016 by liuzhou (log)

[Lisa Shock]

It's not a technique that Le Cordon Bleu teaches...

 

That said, water works great and they don't absorb it. If you're really nervous, wash them in leftover wine.

[dcarch]

Must be promoted by the flour lobby/associations.

I don't wash mushrooms. Of all the "vegetables", mushrooms are very very safe.

 

"------- There are no known cases of foodborne illness attributed to consumption of fresh mushrooms grown in North America, ------"

 

dcarch

[kayb]

5 hours ago, Lisa Shock said:

It's not a technique that Le Cordon Bleu teaches...

 

That said, water works great and they don't absorb it. If you're really nervous, wash them in leftover wine.

Who has leftover wine???

[chefmd]

I had to google "left over wine" and did not find any reliable links

[Anna N]

43 minutes ago, kayb said:

Who has leftover wine???

That was going to be my question. What's leftover wine?

[TicTac]

Mushrooms don't absorb water??  What?!?!

 

Mushroom's are nature's sponges.  You never wash a mushroom!  Take a brush and remove any dirt cut the stems, but do NOT wash your mushrooms (unless you like soggy, mushy, watery nonsense; of course).

[Anna N]

1 minute ago, TicTac said:

Mushrooms don't absorb water??  What?!?!

 

Mushroom's are nature's sponges.  You never wash a mushroom!  Take a brush and remove any dirt cut the stems, but do NOT wash your mushrooms (unless you like soggy, mushy, watery nonsense; of course).

Whoa.  I think that has been loudly debunked.  I know Jacques Pepin rinses his mushrooms. Didn't Alton Brown disprove the theory of mushrooms  as sponges?

[gfweb]

@TicTac That would be the oft-repeated myth of which we speak.

[TicTac]

Myth?
 

Not so.

 

Allow me to substantiate my claim.  As some of you might be aware, I love foraging for mushrooms.  The best time to do so is right after it rains (actually a day or two after, to be exact).  The reasoning behind this is twofold; primarily, mushrooms thrive in damp conditions hence the rain sends them into periods of rapid growth spurts, however; if there is a fair bit of rain or the mushroom is exposed; guess what?  It becomes SATURATED in water.  As in, a mushroom in the same rain storm exposed to the rain vs. one not, will be 3-5x heavier due to the absorption of water.  I have also cooked mushrooms both 'protected from the elements' and others not as lucky and the cooking time is exponentially longer for those saturated fungi and the end result is never as good.

 

The same would be re-created if washed - to a certain extent, but especially soaked, in water.

 

Books and people on the internet can tell you all they want, but until you have seen these beauties in their natural environment and see how the react under different conditions, all that is is hot air!

 

 

 

[gfweb]

I guess one would need to show that water is actually taken into the meat of the mushroom as opposed to being trapped in the gills (which is effectively outside the thing). Gill-trapped water would still slow cooking and make the shroom heavier.

 

 

Edited November 5, 2016 by gfweb (log)

[Yiannos]

I think mushrooms out in the rain and saturated soil for hours/days is a much different thing from a few seconds rinse in the sink. I have cooked mushrooms both rinsed and unrinsed (just brushing any dirt off) and they come out identical. I have not soaked them, but I don't think anyone here is suggesting that at all.

[Alex]

@TicTac, we're now talking about a quick rinse (of whole, not sliced, mushrooms) just before they're cooked, not a soaking akin to "a fair bit of rain." Mushrooms already are largely water, as you undoubtedly know.

 

Cook's Illustrated says:

Quote

...we began to question their ability to absorb more liquid. To find out, we rinsed a batch in cold water, weighing them before and after their wash. We found that six ounces of mushrooms gained only about a quarter ounce of water, and most of this was beaded on the surface.

 

The Kitchn references Gourmet magazine:

Quote

One of the little tips in the front of the July [2008] issue mentions that it's a myth that mushrooms can't be washed. In fact, Gourmet performed an experiment, soaking a bunch and testing how much water they absorbed. It was about one sixteenth of a teaspoon per mushroom — only a bit more than is absorbed by an asparagus, they say.

 

And that's if they soak in water. Ours merely shower.

 

And yes, Alton Brown also debunked that myth. And Mark Bittman says to go ahead and rinse. And hey, if Martha Stewart gives mushroom-washing her imprimatur, that's good enough for me.

[Porthos]

10 hours ago, Lisa Shock said:

 If you're really nervous, wash them in leftover wine.

Makes for happy mushrooms ...

[TicTac]

2 hours ago, gfweb said:

I guess one would need to show that water is actually taken into the meat of the mushroom as opposed to being trapped in the gills (which is effectively outside the thing). Gill-trapped water would still slow cooking and make the shroom heavier.

 

 

 

I can assure you that the water was fully saturated in the meat of the mushroom.  If the opportunity presents itself I will document for you all the differences.  They are most easily noticeable. 

 

Perhaps given the variety of mushrooms I eat are grown in the wild and not mass produced they behave differently.  Who knows.  What I do know is that it is counter intuitive to introduce something you wish to get rid of (and have a little as possible to begin with) in the cooking process.  No reason why a simple small painters brush wouldn't suffice in any cleaning endeavors.  Of the many chefs I have known none wash their mushrooms.

[gfweb]

I just did the experiment.  One mushroom sat in a cup of water for a minute....it was removed and given a light shake to lose surface water.

 

Weight pre bath ...41g and after bath...41 g.

 

 

[gfweb]

Re the necessity of washing mushrooms.  The stuff they are grown in commercially sounds foul, and in fact is, but it is sterilized prior to inoculation with mushrooms.

 

If there is any infection risk it would be from the human hands that touch each one at harvest and the hands that pack them.

 

Assuming, of course, that there isn't willful contamination with a little spit etc. because of a labor dispute or just a bad attitude.  Living where I do in the heart of mushroom country, one hears stories....

 

FWIW I won't eat them raw.

[Anna N]

9 minutes ago, gfweb said:

I just did the experiment.  One mushroom sat in a cup of water for a minute....it was removed and given a light shake to lose surface water.

 

Weight pre bath ...41g and after bath...41 g.

 

 

 I was just debating whether I would do that very experiment.  Decided that sometimes myth-busting isn't conducive to congeniality.   I must be having one of my better days.  I still find it hard to imagine the mushrooms are not equipped by nature with the ability to shrug off rain.  

[gfweb]

I can easily imagine a thin mushroom might dry out easily and then re-absorb water through the same pores through which it exited. But I used a nice plump fresh cremini

[TicTac]

To each his/her own.  No water will come in contact with my beauties!  I am not a fan of button/cremini mushrooms, nor portobello's for that matter - when I do buy in stores it's Oyster/Shitake and if available Chanterelles and Morels.  I do have a client who is a mushroom farmer, I will inquire more about this next I see him. 

 

I can assure you all however, the absorption ability of wild mushrooms is tremendous.

 

 

 

[Alex]

7 minutes ago, TicTac said:

To each his/her own.  No water will come in contact with my beauties!  I am not a fan of button/cremini mushrooms, nor portobello's for that matter - when I do buy in stores it's Oyster/Shitake and if available Chanterelles and Morels.  I do have a client who is a mushroom farmer, I will inquire more about this next I see him. 

 

I can assure you all however, the absorption ability of wild mushrooms is tremendous.

 

 

 

 

No one is doubting you about the ability of wild mushrooms to absorb water (wine, stock, etc.), or is saying you have to start washing yours. What we're saying is that with just a quick rinse, fresh mushrooms absorb a negligible amount of water. This has been scientifically proven; your mushroom farmer's opinion about this is irrelevant.