Soft, mushy, or shriveled cloves
Mold, especially green, blue, black, or white fuzzy growth
Sprouting with a strong bitter taste
Dark spots or discoloration on the cloves
A sour, rotten, or off smell
Slimy or wet texture
Garlic that feels hollow or dried out beyond normal aging
Bulbs with cloves that separate too easily and look deteriorated
Any signs of insect damage or decay
Taste that is unusually bitter, sour, or unpleasant