I’ve never made tempeh, but I’ve heard it can easily overheat. I read something somewhere about making it in water as a coolant somehow. I also know that it is one of the few (only one?) soy prods with no phytotoxins; the fungus destroys them. I think there’s a book called The Book Of Tempeh. There may be a way around the dehulling; I plan to try to make it out of pre-roasted soynuts (I have access to loads) – I suspect the roasting renders the hulls harmless to the fungus growth.

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  Hi,
  Good Idea for a group! I just got a bunch of different starters
  from Gemcultures.com.
  Tried the Tempeh, Quite the task without a grain mill to de-hull
  the beans, but it was good, better than store bought for sure.
  I made the mistake of stacking two of the bags and they overheated
  and did not mold, but instead smelled of ammonia and were slimy.
    Anyone try making Tempeh?
  I'm curious about the ideal cooking time for the beans and do you
  use vinegar? Do you rinse the beans after soaking or cooking?
  I will try Natto next, higher incubation temp but no need to de-hull.
  Holler back if you have ever tried any of these.
  I intend to make a batch of light rice koji for making amazake too.
  Seems that it needs to incubate 2 1/2 days, I'll need a thermostat
  for my ice chest incubator before I take on that one.
  Just the group we need!
  Take Care,
  Beau Barrett
  Pioneer, Ca
  
  
  
  .