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Seeing red over red onions

It happened yet again. I bought a red onion for use in salads, only to find that it is sharper and more acrid than even a regular yellow cooking onion. I have tried soaking the sliced salad onions in ice water, even storing them in the fridge that way, changing the water daily. Doesn't help much. Yet the sweet crunch of rings of red onion is something that I look forward to when getting a tuna salad sandwich at Panera. They must go through a lot of onions, and it's always good.

I once explained my problem to a greengrocer, who said that regardless of color, a sweet onion isn't sweet unless labeled that way, and that usually sweet onions are squatter, with flatter poles, than other onions. I've followed his advice but have never had a good red salad onion and rarely are the sweet white or yellow varieties (even Vidalia) as mild as the ones I eat in restaurants. What's the secret?

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  1. When you find out, let me know. I constantly hear mention of the use of red onions because they are sweeter but haven't found that to be true. I use them when I want the added color but use Vidalias or other sweet varieties when looking for something milder and sweeter than the standard yellow cooking onion.

    1. <I have tried soaking the sliced salad onions in ice water>

      I soak (white) onion slices in warm salt water for 10 minutes or so, to make them taste milder. They lose some crunch, but it's a trade-off I can live with.

      1. There are many varieties of red onions, and each will vary in their tartness or sweetness.

        Do you know which variety you've been buying?

        For example, Flamenco red onions are quite sharp in flavor; while Burgermaster red onions are very sweet and are usually the varieties most restaurants use for salads or for the burgers.

        3 Replies
        1. re: ipsedixit

          I wish I knew what variety is sold. Usually this information is not known or displayed. I don't seem to get much help from produce managers. They are more likely to tell me that they are red onions, duh. I bet most would not know the vast variety of red onions available

          1. re: ipsedixit

            I have no idea what variety - the supermarket bins don't specify. I'll have to check if the stickers on the onions name the variety. I never buy old/dry-looking ones and if there are squat red onions in the bin, I'll pick one of those. If the bins are labeled as "sweet" or "salad" onions it's reasonable to expect that they will not be Flamenco or another sharp variety.

            Since much supermarket produce this time of year comes from the Southern Hemisphere I do not set much store by the Fall/Winter, Spring/Summer distinction parameters.

            I HAVE heard of salting onions to remove the sharpness but I don't think the restaurants are doing this, because their onions are very crunchy. Unless they salt, rinse, then re-soak in cold water. I could try that - since I use very little salt I would not want a salty-tasting onion.

            1. re: greygarious

              I wonder what would happen if you used sugar instead of salt?

              I don't mind sharp onion that much ... if I'm eating it in a reasonable quantity with something else, I'm generally OK with it. In fact, I sometimes find sweet onions too mild.

              I did once buy some exotic purple onions called something like Red Rocket, and they were quite long and narrow. They just about knocked my socks off, and not in a good way ...

          2. gg, do you ever watch Chopped on the Food Network? i just had a Scott Conant moment when i read the title of your post :)

            i've found that the squatter onions are sweeter, but it's also a matter of age, moisture content and storage. younger ones tend to have a bit less of a "bite" to them, and the way the onions are stored during shipping and at the market can impact the sweetness as well. the higher the moisture content, the sweeter it's likely to be. so look for onions that feel "juicy," with nice shiny, tight skins. if an onion looks and feels like it's been sitting around for a while and the skin is very papery or dried out, skip it. you can also use the smell test - if it's very pungent, it's going to be strongly onion-y, not sweet.

            you can also ask the grocer what variety of red onions they are - Italian red onions are sometimes sweeter than other varieties.

            4 Replies
            1. re: goodhealthgourmet

              When Vidalias are in season, I always pick the flatter ones, shaped like a flying saucer is how I describe them.

              Soaking sliced shallots in lemon juice makes a huge difference, IMO, and helps all onions, I believe.

              1. re: c oliver

                I also call them flying saucer onions and they are sweeter
                Onion markets are chaotic and mis-labeled these days
                I often find regular old yellow bulk (in the mesh bag) onions that are fairly sweet
                The whiter the papery skin the more chance your bulk cheap onions will be sweet
                I have bought alleged Vidalia onions that were sharp

                The center slice (at the equator) of all onions is the sweetest part
                It gets spicier as you go to the tips (the poles)
                So many times I save the tips for cooking but use center slices for salad and hamburgers

                1. re: zzDan

                  I had not heard about the sweeet/sharp difference depending on the area of the onion, and will keep that in mind!

                  1. re: zzDan

                    I believe that Vidalias have to have a sticker on them saying that they are.

              2. There are basically only to types of onions. Spring/Summer onions and Fall/Winter onions. Fall/Winter onions are often called storage onions and have less water and more sulphur than the Spring/Summer onions. The Spring/Summer onions are sweeter and have a higher concentration of water in their tissues than the Fall/Winter varieties.
                You might try to look for specific types at your super market. Maui onions are sweet onions, as are OSO, Vidalia and Imperial. OSO come from Texas, Imperials from California.
                Generally speaking, sweet onion season runs from January to about June, Fall/Winter onions fill the rest of the calendar year.
                That doesn't mean you won't find sweet onions a bit later in the year or that you are stuck with sweet onions later in the year. Storage onions (Fall/Winter) are available year round. Sweet onions, because of their higher water content, don't store as well so you're not likely to find them late in the year unless they're imported.
                Hope that helps.
                Oh, yeah; one more thing. No matter how long you soak onions in water you're not going to reduce their bite very much. Water can help remove some of the sulphur but you'd have to cut them very thin to expose enough of the sulphur molecules to the water so siphon them off.

                1. Sorry to hear you have so many troubles. When I want to lose the bite I just dump them in ice water, give 'em a good squeeze, drain, and dump in more ice water, changing the water a couple more times over the course of a half hour or so. But now I wonder if I've only been eating the shadow on the cave wall of the Platonic ideal of which you speak.

                  1. Red onions can be hit or miss if you're expecting them to be sweet. I've tried all kinds of techniques to figure them out. I've tried buying the flat red ones that resemble hockey pucks, I've tried buying the red ones that look like vidalias, I've tried buying the red perfect ball-like variety, and all these efforts proved worthless. So I then fell out of love with the red onion, and made a new sexy latin friend, the Spanish onion. These onions, resembling gigantic oversized globes, are CONSISTENTLY sweet. I have yet to be disappointed by any one of them. As of now, I've converted to Spanish onions.

                    Often times I think that the less than ultimate growing conditions is what contributes to these less than perfect onions we encounter at our markets. Just a hunch.

                    1 Reply
                    1. re: Cheese Boy

                      Red onions are more expensive so one thinks the farmers get more money for them. Maybe they are more concerned with producing and selling them then making sure they are grown properly to be always sweet. Which they used to be

                      I've had good luck with large white onions

                    2. To take some bite out, try lemon juice or lime juice to soak the sliced onion in.

                      1. I saw someone on FN, Michael Chiarello I think, soak onions in milk, you might give that a try.

                        1. Perhaps it's simply a question of what varieties are sold where, but in Tessa Kiros's cookbook "Falling Cloudberries" she says to soak the sliced onion - any onion - in salted cold water for at least thirty minutes before serving it raw. I did that with the red onion the salad called for, and I've made a habit of doing it with any raw onion since, and it always works - red, white or brown onions, it doesn't matter. The onion is crisp and sweet, or as sweet as its variety allows, but that sharp edge to the flavor is nicely blunted. My mom-in-law, who likes onions but suffers the effects, has been especially appreciative of this discovery.

                          1. I find them to be hit or miss and seem to have fewer duds in the summer. So it could have something to do with how long they've been hanging around and what temperature changes they've been through.

                            I slice them thinly (will even drag out the cheap mandolin) into a little bowl, squeeze lime or lemon juice all over them and let them sit. It doesn't take longer than 10 mins or so to tame them. I even do this in the summer now . . . oddly, the juice they've been sitting in often doesn't have the nasty taste and sometimes it becomes part of the dressing.

                            1. I've read in a magazine this month, (cooks ill.) that they use 1tbl of baking soda per cup of water. Soak 15min and rinse thoroughly. Haven't tried it yet but seems plausible.

                              1. I've given up on red onions. They're the weepiest, most acrid of all the onions, and the hardest to peel (I refuse to pay an extra $1.20 per lb. to buy pre-peeled ones). I choose to use the sweet onions, with their No More Tears formula and EZ-Peel skin.