Garlic is one of the most potent and, from a health perspectiv most powerful members of the onion family (Allium). Most of the health benefits derive from the more than 100 sulfur compounds it contains, especially allicin, which is responsible for garlic's characteristic scent and flavour. Allicin is formed when the garlic bulbs are crushed, chopped, or chewed. Among the promising health benefits of garlic are that it may protect against stomach and colon cancer, slow the build-up of artery-clogging plaque, prevent the formation of blood clots, help lower blood pressure, reduce the chances of infection, improve nasal congestion and sinusitis.

Buying
Look for garlic sold loose, so you can choose a healthy, solid bulb. Garlic bulbs should be plump and compact with taut, unbroken skin. Avoid those with damp or soft spots. A heavy, firm bulb indicates that the garlic will be fresh. If the bulb feels light, or gives under your fingers, the contents may have dried to dust. Check out the clove formation. A bulb of garlic may contain a "standard" eight cloves, or as many as 40: Choose a bulb with large cloves if you're a garlic lover, peeling a large number of small ones to flavour your favorite dishes can be tedious.

Storage
Garlic has the potential to sprout. If it does, the compounds responsible for its pungency will partly seep into the new sprouts, leaving the bulb itself diminished in flavour. Cloves that have sprouted can still be used, although you may need to include more of them in your recipe to compensate for the milder taste. To prevent sprouting, garlic should be kept in a cool, dark spot. A loosely covered container, out of the sun and away from the stove or any other heat source, will make a good storage place. Garlic will keep from a few weeks to a few months, depending on its variety, its age when purchased, and storage conditions. Check your stored garlic from time to time and remove any cloves that have become shriveled, dried, or mouldy.

Some experts advise against storing garlic in the refrigerator, but it should keep perfectly well there for at least a week or two. Do not put uncooked garlic in the freezer, which will destroy its texture and give it an acrid flavour.

Preparation
To remove individual cloves, peel off the outer layers of skin from the bulb, then pull back on the top of a clove and snap it off at the base. As you remove cloves, be careful not to pierce the skin on those remaining; even a slight nick will speed decay.

To peel garlic cloves, place them on a cutting board and lay the flat side of a broad knife on top. Tap the knife with your closed fist: A fairly gentle impact is all that's required to split the paperlike skins without smashing the cloves (though no harm is done if the cloves are smashed unless you want to keep the garlic cloves whole; for example, if you were pickling them and wanted them to be attractive).

To chop garlic, cut the cloves in half lengthwise. Make several cuts the length of the clove with the tip of the knife, then cut crosswise. The finer garlic is chopped, the more powerful it will be.

If you plan on cooking garlic, let it stand for 10 minutes after chopping or crushing it. The majority of garlic's health benefits are the result of the conversion of the sulfur compound alliin to allicin that occurs when the cloves are chopped, crushed, or chewed. If garlic is cooked immediately after chopping, allicin never forms and the health benefits are lost.

Be careful not to burn garlic when sauteing, as it will turn bitter. If the recipe calls for onions and garlic to be cooked together, add the garlic after the onions have been sauteed for a few minutes. Garlic takes less time to cook and the juices exuded from the onions will help to protect the garlic from scorching.

Roasting garlic produces a sweet, nutty flavour and a buttery consistency. It can be used as a low fat spread on bread or as part of a sauce. Place the unpeeled bulbs on a sheet of aluminum foil large enough to enclose the garlic. Seal the package, place on a baking sheet and bake one hour in a 375°F oven until the package is soft to the touch. When its cool enough to handle, unwrap, snip the top off the bulb and squeeze out the soft garlic pulp. Roasted garlic will keep several days in the refrigerator. Keep in mind that the heat will inhibit the formation of allicin.

If you love garlic but find the taste of raw garlic too sharp, drop peeled garlic cloves into a saucepan of boiling water and boil for two minutes. Drain and proceed with the recipe. As with roasting, the health benefits are diminished, but the flavour remains.