Stir together the ⅔ cup warm water, rice vinegar, and sugar until the sugar dissolves. If you like you can heat it on the stove over low heat then let it cool completely.
Place the garlic and gochugaru (if using) n a glass jar. Cover with the vinegar-sugar mixture and cover tightly. Depending on your jar, you might need to double the pickling solution. Let pickle in the fridge until desired. Pickled garlic usually takes 2 weeks. The garlic becomes more mellow the longer the pickling period.
