If the garlic is fresh from your garden, make sure to clean and trim all garlic heads. If bought from the supermarket, it is likely clean and ready to go.
Wrap the garlic heads in parchment or freezer paper. Then, to help keep them sealed, you can wrap them again with aluminum foil over the paper.
Place the wrapped garlic heads inside a stainless steel pot (if using the proofer method), or into your slow cooker or rice cooker. If using a black garlic fermenter, follow the instructions that came with your particular fermenter.
If using a proofer, place the stainless steel pot into the proofer and set it to 60ºC/140ºF. If using a rice cooker or slow cooker, cover with the lid and set to "keep warm" setting.
It's a good idea to mark your starting date somewhere on the outside of your cooking appliance. (Yes, you can see we live a Spanglish lifestyle.) ?
After a few weeks, you can begin checking on the garlic. Open a clove to check on the color and texture. You want to keep cooking until the cloves are dark brown to black.If yours are still lighter than that, re-wrap the garlic and cook for several more days/weeks. If you feel that it isn't cooking fast enough, you can slightly increase the temperature, keeping it within the range of 60-75ºC/140-170ºF
Once finished, you can remove the garlic and store wrapped, or you can peel the cloves and store them peeled in a sealed container.
Storage: The finished black garlic heads can be stored wrapped and in a glass jar or plastic bag, or the individual cloves can be peeled and stored in a glass jar. While they can be kept at room temperature, they will keep longer if stored in the fridge or freezer.