After garlic is harvested it needs to be cured, and curing takes time. If you try to speed up the process of preserving garlic, by for example leaving it in direct sunlight, you can destroy your garlic crop. So we wait.
You can of course eat garlic at any stage of its development – baby garlic and scapes are both wonderful and uncured garlic has a juicy, fresh taste. But curing is essential to its longevity in the pantry. We also believe that the flavors develop and mature, like fine wine. In cured garlic, you can distinguish among the different flavors of garlic varieties. All varieties of garlic when eaten fresh at harvest have a similar, young taste – like that of beaujolais nouveau.
Curing garlic is the process by which the outer leaf sheaths and neck tissues of the bulb are dried. Warm temperatures, low relative humidity, and good airflow are conditions needed for efficient curing…Curing is essential to obtain maximize storage life and have minimal decay.
Garlic flavor is due to the formation of organosulfur compounds when the main odorless precursor alliin is converted by the enzyme alliinase to allicin and other flavor compounds. This occurs at low rates unless the garlic cloves are crushed or damaged. Alliin content decreases during storage of garlic bulbs, but the effect of time, storage temperatures and atmospheres has not yet been well documented. (postharvest.ucdavis.edu)