Last year at the Torrance, California, robata bar Torihei, I came across a miraculous hot sauce called Yuzu-it, a briny spicy-sour condiment with subtle herbal notes that I found myself dousing on everything from chicken hearts to squid to grilled avocado. It's made from green chiles, vinegar, sea salt, and most importantly, the juice of the Japanese citrus fruit yuzu, a knobby hybrid of the sour mandarin orange and the lemonlike Ichang papeda. This highly fragrant sour fruit, as you might have noticed, has been a trendy fine dining ingredient over the last decade or so. Yet rarely do you ever see it or its byproducts available in retail establishments.
I spent the rest of that trip searching southern California Japanese groceries for the hot sauce (it's manufactured in Baldwin Park, CA) to no avail, and I'd pretty much given up on it until a few weeks ago when it was on display at Mitsuwa (I could populate a blog devoted solely to the wonders of the Arlington Heights Japanese superstore). At the time Mitsuwa was in the midst of a relative yuzu boom. You could buy the actual fruit in the produce section, several varieties of yuzu-laced ponzu, and tiny jars of yuzo kosho, a kind of fermented salsa made with yuzu zest, salt, and chiles. As of yesterday these were mostly gone, but Mitsuwa still has a few jars of Yuzu-it, which is kind of like liquified yuzu kosho. They're $4.99 a bottle, and you better grab them fast. There are only a couple dozen or so left, and I don't know if they're coming back when they're gone.
Obligatory cooking note: personally, I wouldn't adulterate Yuzu-it, but its distributor, the Mutual Trading Company, Inc., has a few recipes, including Yuzu-it miso and Yuzu-it mayo. Knock yourself out.