Rinse and soak dried soybeans for 8 to 12 hours
Remove the skins by rubbing and rinsing the beans
Drain the beans well
Boil the beans for 30 to 45 minutes until just tender
Drain thoroughly and let the beans dry completely
Mix the cooled beans with tempeh starter culture
Add a little vinegar if needed to help prevent unwanted bacteria
Pack the mixture into a perforated bag or container in a thin, even layer
Keep the package at about 30 to 32°C
Incubate for 24 to 48 hours
Check for firm white growth binding the beans together
Refrigerate once fully fermented