When your burger arrives, steaming hot, perfectly greasy, pre-cheese congealing and all that good stuff, you have a decision to make. Next to the fries are a lettuce leaf and a slice each of tomato and red onion. Which are going on your burger, and which will be left behind? I sincerely hope if you crown your burger with any of them, it’s the onion.
There are some foods that are simply better with the addition of raw onion, foods that almost seem naked without them. Chili, for instance, or tacos from the taco truck, sprinkled with those pungent crystalline shards. Make friends with sulfenic acid, the chemical compound that makes you tear up when chopping and is responsible for the onion’s trademark “stank,” and get to know what these odiferous bulbs can do to a boring lunch.
Bitter, astringent foods like onions boast a special quality you may have recognized in wine: the ability to cut through fat. My secret weapon when it comes time to battle with seriously heavy sandwiches like the Reuben is to supplement the tart but frequently soggy sauerkraut with a nice, crisp slice of red onion. Not a few rings I poked out, but the whole thing. I swear it makes the pastrami taste better, almost with a hot sauce-like effect. Same for a tuna melt, or a bagel with cream cheese and lox — the fatty richness of the smoked fish combined with thick dairy begs for acid. Some find enough of it in tomatoes. Not me, I get it from a big ‘ol slice of you-guessed-it. Plus, if you’re going to smell like smoked fish for a spell, why not go all the way and add a top note of allium cepa?
The great thing about raw red onions is that they’re the least likely to linger on your breath and…well, ruin your day and the days of those in close proximity. They’re sweeter and milder, with a lower concentration of sulfenic acid. That’s why they’re great to add to a sandwich or salad. Use yellow and white onions for cooking, or get used to that nose-wrinkling “what did you eat for lunch, exactly” face.