Alliums: Onions, Garlic, Shallots & Leeks

Alliums are aromatic vegetables in the onion family. Their sulfur compounds create sharp flavor when raw and sweeter, rounder flavor when cooked. This guide compares common alliums and explains how to buy, prepare, store and use them.

Common alliums

• Bulb onions include yellow, red and white onions. Yellow onions are the most versatile; red onions are often used raw or pickled; white onions have a clean, assertive flavor.
• Shallots form in clusters and offer a mild, refined onion flavor that works well in vinaigrettes and pan sauces.
• Scallions have a small white base and hollow green tops; both parts are edible.
• Leeks have a mild flavor and layered leaves that trap soil, so they should be split and washed carefully.
• Garlic becomes more pungent as it is cut more finely and mellows with gentle cooking.

Buying, preparation and storage

Choose firm, dry bulbs without mold, soft spots or green shoots. Store whole dry onions, shallots and garlic in a cool, dark, well-ventilated place. Refrigerate leeks and scallions. Keep cut alliums covered in the refrigerator. For cleaner cuts and less crushing, use a sharp knife; rinse sliced leeks in several changes of cold water to remove grit.

History

With origins in Central Asia, wild onions were likely consumed for thousands of years before being domesticated and selected for cultivation. Wild onions were also likely a staple in a prehistoric diet and perhaps some of the first foods used principally to flavor another food.  It is commonly agreed that onions, garlic and other alliums were first cultivated over 5000 years ago and simultaneously from Iran and Pakistan, throughout China, India and Egypt. The alliums, particularly onions and garlic, were some of the least perishable crops and could be grown in a variety of soils and climates. Onions and garlic were not only an important food but were strongly favored for their medicinal qualities.

In Egypt, the cultivation of various alliums can be traced back to 3500 B.C. The ancient Egyptians deified the onion. The onion symbolized eternity to the Egyptians who buried onions along with their Pharaohs. The Egyptians saw eternal life in the anatomy of the onion because of its circle-within-a-circle structure. Egyptian priests were depicted holding onions in their hands or covering an altar with a bundle of their leaves or roots. Egyptian priests were forbidden from eating garlic to ensure their celibacy. In mummies, onions were frequently found in the pelvic regions of the body, in the thorax, flattened against the ears, and in front of the collapsed eyes. Flowering onions have been found on the chest, and onions have been found attached to the soles of the feet and along the legs. King Ramses IV, who died in 1160 B.C., was entombed with onions in his eye sockets. Egyptologists theorize that onions may have been used because it was believed that their strong scent would prompt the dead to breathe again.

Onions, garlic and leeks, along with cucumbers, melons were mentioned in the Bible as the  Israelites lamented the meager desert diet enforced by the Exodus.

In India, the onion was used as a diuretic and was considered good for digestion, the heart, the eyes, and the joints. Likewise, Dioscorides, a Greek physician in first century A.D., noted several medicinal uses of onions. The Greeks used onions to fortify athletes for the Olympic Games. Before competition, athletes would consume pounds of onions, drink onion juice, and rub onions on their bodies.

Though the Romans did not imbue onions with the same spiritual significance as the ancient Egyptians, the Romans did eat onions regularly and carried them on journeys throughout the Europe and the rest of the Roman Empire. The Romans believed the onion to cure vision, induce sleep, heal mouth sores, dog bites, toothaches, dysentery, and lumbago. The Roman gourmet Apicius, credited with writing one of the first cookbooks (which dates to the eighth and ninth centuries A.D.), included many references to onions. Onions played a vital role in the diet of the poor of Rome, and were held in some contempt by the wealthy elite. The strong smells of garlic and onions were considered vulgar.  Leeks, having a milder taste and odor, were more acceptable in the upper levels of Roman society.

After the Romans introduced the onion (and other alliums) to other parts of Europe, the onion was soon established as an important part of the European diet. By the Middle Ages, the three main vegetables of European cuisine were beans, cabbage, and onions. In addition to serving as a food for both the poor and the wealthy, onions were prescribed to alleviate headaches, snakebites, and hair loss. They were also used as rent payments and wedding gifts.

In France, onions were associated with sexual potency.  King Henry IV was said to have the sexual potency as strong as his breath, ostensibly from eating a prodigious amount of onions. Although onions were important in dietary and medicinal terms in medieval Europe, the Roman inhibitions and prejudices about how onions smell and the effect they have on an individual’s moral character also prevailed.

Despite their associations with the lower rungs of society, onions, garlic and leeks continued to be popular in British cooking until the 17th century. Eating them raw, however, began to be frowned upon and was seen as a social taboo, particularly for women or those who held social pretensions or aspirations. By the end of the 17th century, there was a significant social prohibition against garlic specifically and to a lessor extent onions and leeks.  Onions, garlic and leeks were by now associated with peasant food.

European settlers brought cultivated onions to North America, where many wild alliums already grew. Indigenous communities used wild onions in food, seasoning, syrups, poultices and dyes. The name Chicago is often linked to an Indigenous word associated with the wild garlic or ramps that grew in the area.

Throughout Anglo-Saxon Europe and much of the United States, the social taboo surrounding the effect of onions and garlic on human breath and sweat lasted for almost three hundred years. Though onions, leeks, and garlic were certainly still eaten, the smell of them was considered socially impolite and a mark of low breeding. Outside of Europe and the United States, Japan is the one country in Asia to hold similar associations with the smell of garlic and onions.

Types of  Onions

Onions are divided into two categories, green onions and dry onions. Dry onions are further divided into sweet (spring/summer) and storage (fall/winter) onions. The storage onion is not as sweet, with a stronger, more pungent aroma and flavor. As the name indicates, storage onions keep for long periods of time when properly stored.

Dry Onions

Yellow Onions

Yellow onions or Spanish onions are the most common type of storage onion. Bermuda, Maui, Walla Walla, Vidalia and Texas Sweet are sweeter varieties of yellow onion.  These sweeter versions have less of the sulfur compounds found in the more common and pungent onion varieties and may be preferred when eaten raw.

Red Onions

Red onions are often milder and sweeter than yellow onions and work well raw in salads, salsas and sandwiches. They can also be pickled, roasted or grilled; their purple-red color may soften or darken with heat.

White Onions

White onions are more consistent in size and shape than ed or yellow onions and tend to have a fairly strong taste.  Their large sizes makes them good for stuffing and baking. This is the preferred onion in Mexican and Latin American cooking.

Shallots

The word shallot comes from Ascalon, an ancient Israeli city where the shallot is thought to have originated. Different from onion, shallots form like garlic, with a head composed of multiple cloves, each covered with a thin, papery skin. Shallots are favored for their mild onion flavor and can be used in the same manner as onions where the bulk of the onion isn’t desired.

Pearl Onions

Are usually just small immature varieties of red or yellow onions commonly used for pickling.

Cippolini Onions

Are small flat onions with a strong yet sweet taste. Because of the unusual shape, cippolini are usually cooked whole.

Green Onions

Scallions

Scallions, green onions, or spring onions have a white base that has not fully developed into a bulb and green leaves that are long, hollow and straight. Both parts are edible.

Ramps

Ramps are a wild onion grows from Canada to the Carolinas and resembles a scallion with wide leaves. Also known as wild leek, ramps have a strong, garlicky-onion flavor. The root ends are trimmed before using. Though the flavor of a ramp is slightly stronger than the leek, scallion or onion, it can be used—raw or cooked—in many dishes as a substitute for any of those three.

Leeks

The leek is related to both the garlic and the onion, though its flavor and fragrance are milder and more subtle. It has a thick, white stalk that’s cylindrical in shape and has a slightly bulbous root end. The broad, flat, dark green leaves wrap tightly around each other like a rolled newspaper. Rootlets and leaf ends are trimmed before using. Slit the leeks from top to bottom and wash thoroughly to remove all the dirt trapped between the leaf layers. Leeks can be cooked whole as a vegetable or chopped and used in salads, soups and a multitude of other dishes.

Garlic

Garlic is the most pungent and flavorful of the Allium family. There are two main categories of garlic: soft neck, with a pliable papery core, and hard neck, with a stiff wooden center core. The hard neck varieties are easier to peel and have a bright, intense flavor. Elephant garlic, not a true garlic, grows into larger heads with larger cloves and has a relatively very mild flavor.

Other Forms of Garlic

Dehydrated garlic is ground into a fine powder to form garlic powder or a coarser grind for granulated garlic. Garlic salt is garlic powder blended with salt and a anti-caking agent. Garlic extract and garlic juice are derived from pressed garlic cloves and while considered a  convenience product, are a poor flavor substitute fresh garlic.

Whole, pre-peeled garlic cloves are generally considered an acceptable substitute for freshly peeled garlic but have a shorter shelf life and must be kept refrigerated.

Pre-minced garlic may be packed in water, oil or acidified brine. It is convenient, but its flavor is usually milder and less fresh than garlic minced just before cooking. Refrigerate opened containers and follow the label’s storage directions.

Other Forms of Onion

As with garlic powder, onion powder is ground, dehydrated onion. Onion salt is onion powder blended with salt and often an anti-caking agent. It is a common component of spice mixtures such as seasoned salt. Onion flakes are minced onions that have been dried. And, as with dried garlic products, the flavor of dried onion is substantially inferior to fresh.

Dried shallots are mostly seen as dried slices and used commonly in South and Southeast Asian cooking.

Buying and Storing Alliums

Storage onions are generally available year-round. When purchasing yellow, red, and white storage onions should be firm and heavy for their size.  The onions should be absent any signs of mold or sprouting green tops, a sign of an old onion.

Leeks are best purchased from early autumn to the end of winter. Leeks should have a long length of white and roots that aren’t dried out. Scallions are available year-round but are at their peak during spring and summer. Scallions should be crisp with bright green tops and a firm white base.

Garlic’s peak season is the middle of summer.  Heads should be firm, heavy for their size with no with papery husks. Garlic heads should be absent of mold or green sprouts.

Storage onions, shallots and whole garlic should be kept unrefrigerated in a cool, dark place with some air circulation. Leeks and scallions should be stored refrigerated covered with high humidity.