Every year, Lori has a birthday. As her greatest fan and loving husband, I am always on the lookout for gifts worthy of that occasion. Thus, I was pretty excited this winter when we found the shelf mushroom fomes fomentarius (see this post).
About 500 years ago, before TV, cars, big box stores and twitter, people were much smarter than us.

When they ran across a mushroom such as fomes fomentarius, they thought things like “I wonder if this fungus would be useful for starting fires“. And as they sat around the fire, eventually someone thought “hey, if we breakup that mushroom, mix it with water and ashes from our fire, I bet we could make really awesome hats.” Thus the mushroom hat was born:

This picture is from the September/October 2007 issue of the newsletter of the North American Mycological Association. They have a great article about making such hats.
At this point, I am sure you are wondering what the ashes are for. I was wondering that too and then I remembered a book I read a few years ago called “Caveman Chemistry“.

This book is a great read. In it, there is an entire chapter devoted to making potash from ashes. Potash is an old-timey word for potassium carbonate K2CO3. Back in the day, it was an incredibly important chemical. Potash is mildly caustic. This is why ash paste used to be put on wounds to prevent infection. On an industrial scale, potash was used to make lye (KOH) which is a very caustic substance that is useful for making soap and paper.
Stealing from Wikipedia:
Potash production provided late-18th and early-19th century settlers in North America a way to obtain badly needed cash and credit as they cleared their wooded land for crops. To make full use of their land, excess wood, including stumps, needed to be disposed. The easiest way to accomplish this was to burn any wood not needed for fuel or construction. Ashes from hardwood trees could then be used to make lye, which could either be used to make soap or boiled down to produce valuable potash. Hardwood could generate ashes at the rate of 60 to 100 bushels per acre (500 to 900 m3/km2). In 1790, ashes could be sold for $3.25 to $6.25 per acre ($800 to $1500/km2) in rural New York State – nearly the same rate as hiring a laborer to clear the same area.Potash-making became a major industry in British North America. Great Britain was always the most important market. The American potash industry followed the woodsman’s ax across the country. After about 1820, New York replaced New England as the most important source; by 1840 the center was in Ohio. Potash production was always a by-product industry, following from the need to clear land for agriculture.
Back to the hat - the ashes were needed to break down the fibers of the mushroom in the same way that lye is used to make paper. But where could we get ashes??? Hey wait - we heat our house with wood in the winter. We probably go through 150 pounds of would per day. We generate LOTS of ashes. According to Caveman Chemistry, the ash from burning 1000 pounds of Beech contains 0.9 pounds of potash. Never mind that we were burning mostly white oak. A tree’s a tree. It seemed like we were in business.
Extracting potash from ashes is dead easy. Potash is extremely soluble in water; you just mix the ashes with water and a clear liquid comes out that is mostly potassium carbonate and water. Evaporate the water and you should get nice crystals of potassium carbonate.
Here is my rig; it consists of two five gallon plastic buckets. The top one has small holes poked in the bottom. Every day, I dump the ashes in the top bucket, add water and catch the resulting liquid in the bottom bucket.

(I wonder if we can get some product placement money for this photo).
I used a teflon baking pan as an evaporator. Here it is, on it’s side, with sunlight. I was trying to show the crystals:

While it may seem kind of fun to make potash, I was really only into it for hat making. For those of you who are fans of chemistry, you will remember that sodium and potassium have very similar properties. Sodium carbonate is just baking soda - not too exciting (potash is potassium carbonate). It seemed like I was making super-baking soda.
Then one day, the holes in the top bucket got plugged, so I was opening them with a nail and the potash water was dripping on my hands. As my hands got wet, I noticed my fingers were feeling slippery. Have you ever noticed how your hands feel slippery when you get bleach on them? That is because bleach dissolves your tissue. The slipperiness is from the fats in your skin as your skin dissolves…cool. So this potash water was pretty strong. Even better, I ended up with chemical burns on the skin on the back of my hands. A few days after that, the evaporator pan started to dissolve, so I switched to plastic.
With potash production moving along at full speed, it was time to get serious and find some more of these shelf fungi. In the past, when I was not looking for them, it seemed like they were everywhere. Now that I was looking for them, I could not find any. To make matters worse, I was not making anywhere near 0.9 pounds of potash per 1000 pounds of wood.
Which brings me to the end of this chapter. I will not be presenting Lori with a fabulous mushroom hat for this birthday. But I have not given up on the dream. Here’s the plan. I am going to ask Lori to help me find more of these shelf mushrooms. I am sure that by fall we will find enough for a hat. When we find enough, I will buy lye from the hardware store and we can make the hats without potash. If that works, then I will try with potash. Stay tuned…