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seachangeau

how do I perform a KOH test?

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can someone plese tell me how to perform a KOH test exactly perferably using some other easily available kitchen friendly base? david aurora mentions this test on certain bleeding agarics. i want to test my garden finds.

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Yes I have been unable to find KOH in pharmacies.

you need 5-10% aqueous solution of KOH, place small sample of the fungi on slide and treat with the KOH. never having done it i assume the hyphae or spores will change colour.

Edit:

KOH (Potassium Hydroxide)

A 3-5 percent aqueous solution is used to test for color changes. Consult your pharmacist for help in obtaining this chemical, or ask the mycologist at a local university (be nice!)--or purchase KOH online at a scientific equipment site like Fisher Scientific(though you may have some difficulty with this post-911).

KOH is used in the identification of many mushrooms, includingboletes, polypores, and gilled mushrooms. For boletes, place a drop of KOH on the cap, stem, sliced flesh, and pore surface. For polypores, apply the KOH to the flesh and the cap surface. For gilled mushrooms, place a drop on the cap surface. Note any color changes that take place. A change to yellow is sometimes found in species of Agaricus and Amanita; magenta or olive reactions can help identify species of Russula and Lactarius; deep red or black reactions can help sort out many gilled mushrooms; black reactions among polypores are crucial separators; and various colors are produced with boletes. Don't forget that a "negative" reaction (no color change) may also be an informative character!

I have heard that liquid Drano may (may) work as a substitute for KOH; I have not experimented.

http://www.mushroomexpert.com/macrochemicals.html

Cheers, Ob.

Edited by obtuse
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You can get KOH from soap maker suppliers or alternatively contact me and I can send some out. Otherwise household Ammonia will also work.

Like obtuse pointed out you will need a 5-10% aqueous solution of KOH(Potassium Hydroxide). You use this to observe any colour reactions/changes when dropped onto various parts of the fruit body.

Here's a link with some information you should find useful>>http://www.mushroomexpert.com/macrochemicals.html

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