As the sketch on the right shows, 
an insulated container is used as an incubator to provide a warm and moist environment for a tray of inoculated soybeans.
We have tested the little red 48 qt cooler, a 100 qt cooler, a food storage bin and an insulated pan carrier.
We had the best results using the (Cambro) Insulated Food Pan Carrier (on the bottom right).
How to make our tempeh incubator------ How to make Betsy's Tempeh