How much yield should I expect from a mushroom block?

A common measure is biological efficiency, the fresh mushroom weight as a percentage of the dry substrate weight. Oysters often reach 75 to 150% or more across all flushes, meaning a block with 1 kg of dry substrate can yield roughly 0.75 to 1.5 kg of fresh mushrooms. Species, strain, and conditions all shift the number. First flushes are the most productive.