“New” Onions
Called shin-tamanegi (新玉ねぎ) in Japanese, new onions are an eagerly awaited spring vegetable. They’re regular yellow onions that are harvested early in the year, when the onions are luminously white, crisp, juicy, and sweeter and less pungent than fully matured and cured yellow onions produced in the fall. While new onions’ qualities are similar to those of varieties of sweet onions, such as Vidalia, Walla Walla, and Maui, new onions remain different because they generally have a spicier, more complex flavor than sweet onions.
The most famous new onions in Japan come from Awaji Island and are prized for their high sugar content and mild taste. Awaji was one of the first places that yellow onions were grown in the country starting in the mid-1880s. Initially, yellow onions were used to make the growing array of Western dishes introduced into Japan in the late 19th and early 20th centuries. Over time, they were incorporated into all kinds of recipes because they tick the fundamentally important culinary box of being a vegetable high in umami and are a type of onion with an appealing more spicy, pungent flavor than the delicate-tasting leeks, called shiro-negi or naga-negi, that are traditionally found in Japanese cuisine. Awaji’s farmers supported the adoption of yellow onions into Japan’s quick, fresh ingredient-oriented way of cooking by creating new onions; a yellow onion that can be eaten raw—people will brush off any dirt and remove the wispy outer layer of skin and bite into them pulled straight from the ground—and used fresh in salads, on sandwiches, as garnishes for fish and meat dishes and added to dressings and dipping sauces. New onions are also featured in many quick-pickle, stir-fry, and steamed dishes, when some light cooking accentuates their flavor and increases their ability to absorb seasonings. As a result, today, yellow onions are the second-most consumed vegetable in Japan.
If you’re traveling in the Setouchi region in spring, look for new onion dishes at restaurants from March through May. Popular standards include onion ohitashi, onion steaks, and onion rice. If buying new onions, seek out ones that are ivory white and have barely have a wisp of skin on them. Be on the look-out for soft, brownish bruises, which are a sign that the new onion has started to deteriorate. Because they’re shipped immediately after harvesting and do not undergo the curing process of air drying which is applied to fully-mature yellow onions, new onions are more perishable. They should be kept in the refrigerator or other cool, dark, well-ventilated space, and used within a few days.
After May, yellow onions are left in the ground on Awaji Island until they are harvested as mature yellow onions in August and September. These second season yellow onions are considered all-purpose “cooking” onions, used year-round in simmered and long-cooked dishes, like stews and curries, and in rich dishes that are strongly flavored. Setouchi cooks will sometimes use both new onions and mature yellow onions in these dishes, with mature yellow onions added at the start of the cooking process to provide flavor and body and lightly sautéed new onions added at the end to provide sweetness, heat, and texture.