Two years ago, my supply of stable dobai 土灰 dried up. I bought up the remaining stock from the supplier, but that didn’t last long. When I switched to another source of dobai, the results were far different than what I had imagined. My two main bread and butter glazes haven’t been the same since.
Which brings me to my current predicament of having to basically start from zero and re-formulate these glazes with different ash. Fortunately, I have basic analysis info from the old ash, and also for the new types I will be testing with, so I can use glaze calculation software to calculate substitutions, which I am hoping will give me a head start.
For your daily dose of trivia, the word dobai is rendered in kanji as tsuchi 土, and hai 灰, or ‘dirt ash’ (which makes no sense to me). All other ash has a proper name, like pine ash, oak ash, fern ash, etc… I finally found a possible explanation for this odd name the other day when I was searching for ash sources on the net. Turns out the ‘do’ of dobai is actually shortened from the original name ‘kamado’, which is a large pot used for roasting, cooking, burning stuff, etc. It is easier to say dobai, than kamadobai, after all, I guess…
Here are my 3 main candidates for testing:
I picked up one kg of each, and will narrow it down to just one. They are all about 10 dollars/kg, expensive right? I make my own pine ash because I have a good source of already burned pine, but I’m not set up to process large amounts of ash, and when it is all said and done, spending 10 dollars or more per kg is cheaper than the time and sweat put into making my own ash. Rice straw ash is more expensive at almost 20 dollars per kg and it is still worth it when you take into consideration the gathering, burning, quenching, floating, stamp milling, 2nd floating, (ball milling in some cases), and drying process this ash requires.