The first step in this rye grain spawn recipe is combining equal volumes of rye grain and water in a jar, typically 175g rye with 230 ml water for a 720 ml jar. Having done that, tighten the jar lids loosely and cover them with two layers of tinfoil. To sterilize, place your grain jars in an autoclave or pressure cooker for one hour at 15 PSI. Afterward, shake the jars to mix wet and dry kernels before letting them cool down completely. When it comes to inoculation, remember that cleanliness is paramount. Use sterile techniques throughout this procedure — it's crucial when learning how to prepare rye berries for mushrooms. After inoculation, loosen the lids again to allow air exchange – another key part within the 'rye grain tek'. Store these jars in a clean location free from drafts while colonization occurs.