Mushroom Grain Spawn: Sterile Wheat Overgrown with Mycelium, Sinden 1932

Spawn used to be composted, washed manure packed into bricks, or into bottles that had to be smashed to get it out. James Sinden of Penn State patented spawn on cooked, sterilised grain instead. Every grain ends up coated in mycelium, the spawn shakes out of its jar, and it can be sown in rows like seed. Source: J. W. Sinden, US 1,869,517 (1932), written for the field mushroom (Agaricus). The starter is a pure culture, here from the tissue-culture blueprint.