Yuzu is a citrus fruit, roughly the size of a tangerine. It’s often picked green but it eventually turns to yellow-orange. Look it up in a Japanese dictionary and it will say “Japanese citron.”
The green fruit does produce some exceedingly sour and delicious juice, but the more mature fruit is not very juicy at all; it is valued for its fragrant floral-scented zest. If you smelled it blind, you’d think it’s a combination of lemon, mandarin orange, and grapefruit.
It used to be pretty impossible to find fresh yuzu outside Japan, but lately I see, to my great delight, more and more nurseries that will sell you a dwarf yuzu tree. I know one man in Oakland who tends to what is the most beautiful yuzu tree I’ve ever seen; it must have at least 300 yuzu on it!
Bottled yuzu juice — which is almost as good, and certainly more convenient — is becoming widely available in Asian markets, especially Japanese markets. A 10-ounce bottle will cost you around $12, but it will last a long time (at least two or three months, even using it regularly).
Yuzu powder — dehydrated and pulverized yuzu zest — is also becoming increasingly easy to find. Doing a Web search for “yuzu juice” will yield a list of online purveyors.
In Japan, its zest is used mainly to accent cooked vegetables, hotpots, custards, and fish, and it’s sometimes added to miso or vinegar to infuse them with its floral wonders. Juice from green yuzu is often mixed with soy sauce to form a dipping sauce known as ponzu. And Japanese women love to put cut-up yuzu in their baths. How I wish I had enough fresh yuzu to use for this purpose!
I like to use a small amount of yuzu juice — its intense power means that one must be careful of quantity — in braising liquids for fish and vegetables, and sometimes combine a little with raw tuna and eat it spooned over good bread. It’s also delightful mixed into a spoonful of miso, and then spread on fish and broiled. Or try some in a salad dressing along with some good olive oil, yogurt, and maple syrup. You can pretty much use it anyplace you’d use fresh lemon.
Hunt it down (I get mine at Nijiya in SF) and let us know what you do with it!