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Searcher (Novice)
Posted on Monday, November 11, 2002 - 04:50 am:Edit Post Quote Text Delete Post Print Post Move Post (Moderator/Admin Only)

SHROOM DRYING

How come my shrooms never seemed to dry according to my understanding of the published literature? If the weight ratio of wet to dry is 10:1 - shouldn’t I expect 10 ounces of fresh mushrooms to reach one dry ounce in my drying chamber?

Repeatedly, however, my final dry weights seemed to be coming down somewhere between 11% to 12% of the indicated wet weight. Well . . . so I thought! After much trial and error, I found that my wet weights were inaccurate. Why? Simply because of a few minutes delay in making my wet measurements. The biggest weight loss starts immediately. Here’s a typical graph of the drying cycle:
Drying 1
Drying 2
Note the sharp drop in weight during the first few minutes following a harvest. In fact, this graph of an accurately measured 4.82 gram mushroom shows a 420 mg weight loss during the first 20 minutes following its harvest. This averages out to 21 mg per minute, which is one reason why there must be no delay in making the first measurement - if that's the one I want to use to forecast a target dry weight. Note how the line goes flat in less than 12 hours of gentle air drying in front of a small fan. Here, the dry weight will remain fairly constant at 10.8% of the original weight in a room with average ambient humidity around 40%. This is when additional drying requires a specially sealed chamber with a drying agent (I’m using calcium chloride).

Now, the drying curve takes on a brand new shape:
Drying 3

But again, most of the drying occurs early in the cycle, and the line finally goes flat. Here, it bottoms out after a couple of days, yielding a dry weight of 9.75% of the wet weight.
One final note: The drying times can be greatly shortened by slicing the mushrooms into thinner strips. For the tables shown above, the slices were left at about ¼ inch. Of course, the drying times will be lengthened if the mushrooms are not sliced (if you want them to still be recognizable as mushrooms in their dried state).

Here’s the key point: whether un-sliced, or sliced very thinly, the drying curves (the shape of the lines on the chart) will remain almost identical, in proportion to those shown above
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mf (Fishbone)
Posted on Monday, November 11, 2002 - 05:57 am:Edit Post Quote Text Delete Post Print Post Move Post (Moderator/Admin Only)

Wow, nice work! That's some good science and useful information. Next time I'll be sure to leave the guys out of the dessicant chamber for a time after picking to speed things up.
By the way, isn't Excel great for this stuff?
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Searcher (Novice)
Posted on Monday, November 11, 2002 - 06:31 am:Edit Post Quote Text Delete Post Print Post Move Post (Moderator/Admin Only)

Thanks for the encouragement. Yes, the work was done in Excel, but I transferred all the cells to Paint Shop Pro to make a quick jpg picture - just because I'm lazy, and haven't taken the time to learn how to post them in an editable format. Hippie's got some great instructions on how to do that, and I do need to pull them out and take a few minutes to learn that next.
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Webby Doodle Doo (Webmycelium)
Posted on Monday, November 11, 2002 - 08:12 am:Edit Post Quote Text Delete Post Print Post Move Post (Moderator/Admin Only)

Yeah its best to fan dry for at least a day before putting them in the dessicant chamber
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big slick (Baddaboom)
Posted on Monday, November 11, 2002 - 02:14 pm:Edit Post Quote Text Delete Post Print Post Move Post (Moderator/Admin Only)

The figure dry weight is gonna be 10% of wet weight is just an approximate figure

I've grown six strains. Some when dried weighed consistently more than 10% of wet weight some strains weighed consistently less than 10% dried

for example my pf's 40 grams wet turned into 3.8 grams dried
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Hippie3 (Admin)
Posted on Monday, November 11, 2002 - 02:37 pm:Edit Post Quote Text Delete Post Print Post Move Post (Moderator/Admin Only)

wow, great post, very informative and well documented, definite archive material.
i never really gave it much thought, a bit surprised at how much was lost so quickly.
definitely concur that a pre-dry in a fan's breeze is very effective at removing much of the water content , esp. during winter when ambient humidity is usually relatively low.
i've also noticed that invitro-grown fruit-bodies run a bit high on solid versus wet, about 12% instead of the expected 10%. i attribute this to the compression of fruits invitro.

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