The Complete Handbook of Garlic

Chapter 1: Understanding Garlic

When you pick up a head of garlic in a grocery store, you are holding a compact storage organ evolved over millions of years for one purpose: to allow a single planted clove to survive the winter and regrow into a new plant in the spring. Understanding this basic biological fact explains most of what you need to know about garlic's behavior in your kitchen, your pantry, and your field. The papery skin, the pungent chemicals, the clove structure — all of it exits to protect the plant's genetic material during a dormant phase and to give it a head start when conditions turn favorable.

Botanically, garlic is Allium sativum, a member of the onion family. It is a close relative of onions, shallots, leeks, and chives, and it shares many of their physical traits, like hollow, strap-like leaves and a shallow, fibrous root system. But unlike a true onion, which typically produces a single large bulb, garlic's bulb is subdivided into a number of distinct segments, or cloves, each in its own tough protective skin. The number of cloves, their arrangement, the tightness of the skin, and the length of time the bulb remains dormant are all traits that vary significantly between varieties and that a professional buyer must learn to assess at a glance.

The key chemical actors in garlic are a family of sulphur-containing compounds. When a garlic clove is intact, it contains a compound called alliin and an enzyme called alliinase,