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Jul 20, 2011 07:17 AM

Does grating an onion change it's flavor?

I tried to make a zucchini pie last night - really a crustless quiche with 4 cups shredded zucchini, 2 cups mozz, 3 eggs, etc..... I figured since i have the grater out, why don't I grate the onion so it melts into the pie.

Well, the pie tastes a bit bitter to me. The only seasoning I added was some marjoram, dash of cayenne, and S&P.

I expected the onion to add some sweetness. I'm tempted to buy 4 more zucchini & see if it tastes better with a finely diced onion instead. Or you all could clue me in. Thanks!

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  1. It will intensify the flavour since grating will damage more of the cells in it. Much like with garlic the more damaged cells, the more intense the flavour.

    Now, I expected you to say it was too watery but not too bitter. In any case I guess there wasn't enough heat to caramelize the sugars so you got a much greater taste of sulfur than that of sugar.


    1. I would think that the onion flavor would meld into the rest of the flavors, as you posited.... I know that one very successful recipe in my binder calls for grated Spanish onion -- Bobby Flay's creamy cole slaw. Not too sharp, here, definitely not bitter (this is raw onion, too, of course).

      1. Here's a current thread on the same subject:

        To avoid the sometimes bitter sulfurous bite of grated raw onion, you could saute minced onion instead, or even the grated, since you'll be cooking it further anyway. The presence of a stronger bite also depends on the variety of onion; yellow onions tend to be stronger flavored, especially when fresh. Try a sweet onion variety as an alternative.

        3 Replies
        1. re: bushwickgirl

          thanks for that link, fascinating!

          And now I must concede that I recalled another ingredient I used - something I do NOT care for - garlic powder - is it possible the bitterness is from that?

          My SO uses it with steamed veggies & evoo - I've had to ask him to stop b/c I don't like the flavor. Looks like I need to try a new zucchini pie with grated onion & garlic!!!

          1. re: Snorkelvik

            Well, I've also run into this bitter onion problem and the bitterness does not cook away. I've encountered it making onion gravies for Indian curries, so the onion gets sauteed a good long time on low heat, with lots of oil (it is not burnt onion). It happens to me when I run raw onion through a blender, but not when I saute chopped onion first and then blend. Also, it does not happen all the time. Perhaps I need to pay attention to the type of onion, when this happens next and when it doesn't. I do sometimes use grated onion and this hasn't happened to me with grated - but perhaps because I grate rarely. Don't like dealing with the slipperiness and a sharp grater.

            1. re: sweetTooth

              Yellow and red onions can be extremely sharp when grated or chopped in a blender or processor. Gentle, long cooking helps. Varies from one onion to the next, within those colors, though even sweet varieties will be sharper if treated in this way, which destroy the cell walls.

        2. Yes, garlic powder can be bitter.

          Did you peel the zucchini (courgettes for the international folks) ? I had a batch of them last week that I actually pitched because the skins were so overbearingly bitter that they were inedible.

          Tried peeling them, but it extended a ways into the flesh, so I just tossed them (they're in season right now, so cheap enough to not get too fussed about a pound of zucchini)