Two summers ago the beer section of the supermarket I normally patronize (Publix, in case you wonder) added something called "grapefruit shandy," made by Leinenkugel's.
As far as I can remember the only Shandy I'd ever heard of was Tristram, but I learned that it's a term for beer combined with lemonade--apparently the default meaning--or some other sweet beverage. I like beer a lot and I like grapefruit juice a lot, so I thought this sounded interesting enough to justify my buying a six-pack. I did like it, and I also tried Leinenkugel's Summer Shandy, which is the lemonade version, and which I liked, but not nearly as much. Toward the end of summer both disappeared from the shelves at Publix.
Last summer I waited in vain for the grapefruit shandy to appear, but only the lemonade version did. I bought a six-pack or two of the latter, but remain unenthusiastic about it. And this summer the same thing happened. Publix does have a Leinenkugel's grapefruit-flavored "spritzen": "beer with a splash of seltzer and natural flavors." I tried it, and...no. It's ok if you like flavored water, though it does have a 4.2 alcohol content and only 93 calories, so I guess it's better than lite beer.
One day last week as I stood inspecting the beer shelves--twice, in case I had missed the grapefruit--it suddenly dawned on me that if grapefruit shandy was literally beer and grapefruit juice, I could, should, and would make my own. So I decided to experiment, and bought a six-pack of my favored relatively light and crisp beer, Fairhope Brewing Company's Cheap Sunglasses, and a carton of grapefruit juice.
I started with a shot (1 1/2 oz.) of grapefruit juice and a can of beer, and it was absolutely perfect. It was as if Edison's first idea for a light bulb had been a total success. I need experiment no further.
I realize these are bottles, not cans. FBC recently switched to cans.
Unless you live in this area you probably can't get Cheap Sunglasses, but I'm sure there are many others that would work just as well. It's described as a kolsch (or rather "kölsch"). I'm not enough of a beer connoisseur to be able to keep the terminology straight in my head for very long, but "pale, highly attenuated, hoppy, bright" (according to Wikipedia) does sound perfect as a companion to the flavor of grapefruit.