What pressure cooker do I need for mushroom growing?

You need a pressure cooker or canner that reaches and holds 15 psi, which is about 121°C, the temperature that reliably sterilises grain. A stovetop pressure canner with a gauge is ideal because it holds many jars, but a smaller domestic pressure cooker works for a first grow. Avoid low-pressure cookers that only reach a few psi, since they cannot sterilise grain.