Get to know the mandelo
Credit: Photo by Kat Kinsman

Late fall and early winter are the glory times for fruit. Y'all can argue with me as much as you'd care to—I'm not immune to the pleasures of sloppy summer peaches and bursting-ripe berries—but weird citrus hits the bins when it’s cold out. A person can surely score a bog-standard orange, grapefruit, lemon, or lime any time of year, but starting in November, and roughly through mid-February (depending on geography and vagaries of climate), a citrus lover is absolutely spoiled for choice at the market, what with all the satsumas, honey tangerines, mandarins, Meyer lemons, Key limes, calamondins, clementines, finger limes, pomelos, and other orbs of juicy joy available for a cruelly short period of time.

I don't bother with choosing—I like to buy at least one of each kind, even if I don't know what it is. That's how I ended up with a mandelo in my kitchen. Only I didn't know that's what it was at the time. The mystery of the big green fruit had been needling at me since last year when I spied it at my favorite Asian grocery store in Sunset Park, Brooklyn, and posted a picture on Twitter and Instagram asking for help identifying it. There were no tell-tale stickers, the bin didn't have a label in English, and the receipt said "pomelo"—but there was a massive mound of pale-green pomelos (sometimes spelled pummelo) an aisle over. I sliced the dark green sphere open to reveal an orange-yellow interior that tasted like a slightly-off-sweet hybrid of a clementine orange and a grapefruit, further mangling my brain. Social media fruit sleuths suggested with great confidence that it was a calamansi, calamondin, melogold, Persian lime, oroblanco, ugli fruit, sudachi, or kabosu. Fruit Twitter is the best Twitter, as I have found repeatedly, but I could not with any confidence decree the fruit to be any one of these. I bought one or two a week until they were gone from the shelves.

And lo, this season they have returned—only this time with stickers. "Cocktail grapefruit" it said. "The heck?" I said. That's the shelf name for a mandelo, which was developed by the University of California's Citrus Experiment Station (now expanded and called the Citrus Research Center and Agricultural Experiment Station) in the 1950s. This juicy, just-barely-tangy marvel is a hybrid of a Frua mandarin (itself a hybrid of a Dancy mandarin and a King tangor—think TANGerine and ORange) and a Siamese Sweet pomelo. According to the CRC-AES's Citrus Variety Collection database, the cocktail grapefruit was "never officially released by the University of California, Riverside, but somehow made it into the public sector." Or as some fruit scholars put it, the variety "escaped" out into the marketplace and was never officially named either as a mandelo or a cocktail grapefruit, but the terminology for the hybrid stuck. The color of the flesh varies depending on where and how long ago and by whom the fruit is grown, but it may mature from green into a warm gold.

A statement on the website editorializes that the variety is "too damn seedy for commercial usage, " which perhaps explains why this fruit befuddled so many of us, but goes on to note that it "makes a good dooryard juice variety … you could love it or hate it." A note you're reading right here says to mix it with gin (it has "cocktail" in the name after all) and ice and enjoy this fleeting fruit for as long as you can find it.