Begin by preparing the garlic bulbs. Gently scrub off any dirt from the outer layers of the bulbs using a clean, dry cloth. Ensure not to remove the cloves from the bulbs or wet them, as this could disrupt the aging process.
In your rice cooker, place the whole, unpeeled, and cleaned garlic bulbs. Arrange them in a single layer, root side down. If you're using multiple layers of garlic, remember to rotate the top and bottom bulbs every few days to ensure even heating.
Set your rice cooker to the "warm" setting. This provides the ideal temperature and humidity for the aging process without cooking the garlic. For those with larger rice cookers, you can stack more bulbs, but maintain the rotation routine.
Around a week into the aging process, check on the garlic for its progress. Since the time required can vary depending on your rice cooker's temperature and the quantity of garlic, it's recommended to do a taste test at this point.
To perform the taste test, select a clove, peel it, and take a small bite. The desired outcome is black, with a sweet, tangy, and slightly chewy texture – reminiscent of a slightly softer gummy bear. The flavor should have a richness akin to balsamic glaze.
Depending on your rice cooker's heat level, the aging process could take up to 3 weeks. Keep monitoring and testing until you achieve the desired texture and flavor.
Once the garlic reaches the desired consistency and flavor profile, it's ready to enjoy. Store the bulbs in an airtight container in the refrigerator. Black garlic can be stored this way for up to 6 months. Peel the cloves as needed, or peel them all at once if you'd like to capture an appealing photo.