Yuzu: The Complete Guide to Japan's Winter Citrus, from Kosho to Kanzuri to Marmalade
Yuzu is the size of a tangerine, the color of a lemon, bumpy as a walnut, full of seeds, and yields about a tablespoon of juice per fruit if you squeeze hard. By any practical measure it is a terrible citrus. It is also one of the most fragrant things that grows on a tree: a scent of grapefruit, mandarin, lime and something resinous and green, so strong that a single fruit perfumes a room, and so prized in Japan that the peel is grated over soup by the pinch, the juice is sold by the small bottle, and the whole fruit is floated in the bath on the shortest day of the year. It has spent the last decade taking over Western restaurant menus, cocktail lists and, via our hot sauce guide, the Noma bottle on our shelf. This is the fruit, the orchards, the four forms it takes, and how to use each one.
What yuzu is
Citrus junos is a hybrid of a sour mandarin and an ancient, hardy citrus called Ichang papeda, and it originated along the Yangtze in China before traveling through Korea to Japan more than a thousand years ago. It is unusually cold-hardy for a citrus, which is why it grows in mountainous parts of Japan where lemons would die, and it is a slow tree; a seedling takes a decade or more to fruit, which is one reason the fruit costs what it does. The fruit ripens from green in early autumn to yellow by November and December, and the peel, not the juice, carries most of the aroma, in oils that are released the moment the skin is scratched.
Kochi and the orchards
Roughly half of Japan's yuzu comes from Kochi Prefecture on the island of Shikoku, from steep river valleys where the trees grow on terraces, and mountain villages like Umaji and Kitagawa have built their entire economies on the fruit. The harvest is in late autumn, by hand, from thorny trees, and most of the crop is processed within days into juice, peel and preserved products because the fresh fruit does not keep or travel well. Fresh yuzu reaches the United States only briefly and expensively, from a handful of California growers, in November and December; the rest of the year the fruit exists here as the products below. Yakami Orchard, whose bottles and jars we carry, works with Japanese growers to press and preserve the fruit near where it is picked.
The winter solstice bath
On the day of the winter solstice, Japanese bathhouses and households float whole yuzu in the hot bath, a custom called yuzuyu that dates to the Edo period. The oils in the skin scent the steam, the practice is believed to ward off colds, and the smell of a yuzu bath on the darkest day of the year is one of the country's small national pleasures. It tells you how the Japanese think about the fruit: as aroma first, food second.
The four forms
Juice. Yakami Orchard's yuzu juice is pressed from the whole fruit and bottled without additives, and it is the most versatile yuzu product for a Western kitchen. It is more aromatic than lemon or lime and slightly less sharp, and it is used by the teaspoon: in a vinaigrette in place of half the lemon, whisked with soy for a quick ponzu, in a zero-proof highball with soda and a little honey, in a margarita or a gimlet, over raw fish or oysters, in a custard or a sorbet. Once opened it belongs in the refrigerator and keeps a few months; the aroma is the first thing to fade, so buy the small bottle.
Yuzu kosho. A paste of yuzu peel, fresh chile and salt, fermented for weeks until the flavors marry, from Kyushu in Japan's southwest. The green version, made with green chile and unripe yuzu, is the classic; Yakami Orchard's green yuzu kosho is sharp, hot, salty and intensely citrus, and it is used by the pea-sized dab: stirred into a bowl of ramen or udon, smeared on grilled fish or chicken before it goes on the heat, mixed into mayonnaise for a dip, dotted onto a raw scallop or a slice of cured ham, whisked into a vinaigrette with the juice. It is one of the most useful condiments in the world and one jar lasts a season.
Kanzuri. From Niigata, in Japan's snow country, a fermented chile paste built on yuzu, salt and koji, the rice culture behind sake and miso. The chiles are salted and then laid out on the snow in winter, which leaches their bitterness and softens them, then blended with yuzu and koji and aged for three years or more. The Kanzuri chili sauce is the result, deeper, rounder and more savory than kosho, with a gentle heat and a fermented depth. Stir it into a pot of beans or a braise, spread it on grilled meat, mix it into a marinade, or put a spoon beside a plate of pasta with sausage for a Japanese-Italian evening that works better than it should.
Marmalade. Yuzu peel is bitter and aromatic in exactly the way Seville orange is, which makes it a natural marmalade fruit. Yakami Orchards' yuzu marmalade is the jar for toast with good butter, for a spoon beside a soft cheese or a slice of aged Gouda on the cheese board, for glazing a roast duck or a ham in the last minutes, and for stirring into hot water with a little grated ginger for the Korean-style yuzu tea, yuja-cha, that is the best cold remedy in East Asia. Our jam and marmalade guide explains why the peel is the point.
Yuzu with the rest of the pantry
Yuzu is citrus, so it goes where lemon goes, and it is aromatic, so it goes where you want a scent to lift a rich dish. A few drops of juice on a tin of oily fish. A dab of kosho on a fried egg. Marmalade with a strong cheese. Kanzuri in a pot of anything slow. A teaspoon of juice in a glass of sparkling tea. The Noma corn yuzu hot sauce on our shelf is a Danish kitchen's version of the same instinct, corn sweetness and chile heat with yuzu on top, and it is the bridge between this guide and the hot sauce shelf.
Buying and keeping
Look for Japanese origin, since most yuzu is grown and pressed there, and for short ingredient lists; kosho should be yuzu, chile and salt, juice should be juice. Refrigerate everything once opened. Kosho and kanzuri keep for months and lose only a little brightness; juice fades faster; marmalade keeps like any preserve. If you ever see fresh yuzu, in a good Japanese market in December, buy two, zest one over everything you cook that week and float the other in a hot bath. The four forms are on our Asian pantry shelf at 263 Josephine Street in Cherry Creek, Denver, and ship nationwide from theambrosianpantry.com. A tablespoon of juice per fruit is a terrible yield and a completely fair price.
