Take some whole heads of garlic - as many as you'd like, but since this recipe takes a while I'd recommend doing as many as possible.
Put them in the pan and cover the container all around in a few layers of plastic wrap, to ensure no moisture can escape.
Add a little damp hay or similar material before wrapping, to help prevent the garlic from drying out.
Once the container is completely sealed with plastic wrap, cover once with a layer of foil. Set your dehydrator to 140 degrees F. If you have multiple shelves in the dehydrator, set your black garlic on the bottom shelf. Feel free to use the dehydrator, if space allows, for other purposes while the black garlic is working.
Be prepared for the wait! The author has found the process to take between 26-35 days, depending on how often the dehydrator is used for other projects, the size of the bulbs, and the moisture content. A noticeable color change may not begin to occur until 15-18 or so days into the process, so don't worry if nothing seems to be happening.
You'll know the garlic is ready by its deeply browned color and sweet, captivating aroma when you unwrap the container.
Store the black garlic in an airtight container until using, and be sure to throw the garlic skins into stocks, soups, and sauces to utilize their flavor as well.