"The is simply mixed with cooked, dehulled soybeans; the continues its growth without the... spores. ...however, [it] generally has a lightly weaker mycelium and the incubation time is a little longer than... sporulated methods. And... there are always some unwanted bacteria in the original tempeh. If you are careless and/or the humidity is high, their numbers will increase with each generation until eventually they prevail, preventing the formation of good tempeh. However, by being clean and careful, we have had no trouble in keeping this starter going for more than 12 generations..."