To begin, pour the half cup of rye berries into your large wide-mouthed Mason jar, and top with a cup of water. Put this aside, and allow the berries to soak in the water for around 8 hours, or overnight if you can manage it. You can make as much as you want, but make sure you soak only half a cup of rye berries per jar.
Once this time period has elapsed, drain all the water from the jar, and then replace the lid of the jar with a square of clean cheesecloth – you can secure it by fastening it in place with a rubber band, or some twine. If you are unable to acquire cheesecloth for this purpose, any mesh fabric that is effective for straining purposes will do.
After the cheesecloth has been secured over the top, line all your jars up onto a dish rack, and cover them all with a towel. Let them sit in a cool dry place – rye berries will take around 2 days (or 48 hours) to sprout.
During the sprouting process, you will need to rinse the berries around 3 times a day, or every 6 to 8 hours. To do this, simply hold the jar under running water, allowing the water to run into the jar through the cheesecloth lid. Wait until there is enough water to cover all the berries, then swirl the jar around before draining it by turning it upside down and giving it a couple of shakes to get rid of excess water. After rinsing the berries, put the jars back on the dish rack, and cover them with the towel.
Repeat this process of rinsing until the berries begin to sprout. The sprout will be around the same size as the berries, if not larger, and after they sprout, your berries will double or triple in size. Once they sprout, it is vital to properly dry the sprouts, or they will spoil very quickly.
To dry the sprouts, lay down two layers of paper towels on your counter top, spread the berries out on this in an even layer, and place another layer of paper towels on top. Then, press down gently, and allow the sprouted berries to sit in the paper towels for an hour, so any additional moisture can be soaked up by the paper towels. Once they are dry, the sprouted rye berries are ready for use.