I plan to make a BIG pot of onion gravy soon. Is there a rule of thumb about the volume and weight relation of sliced onions?

So, my big pot holds about 12l - I’d go for 10l here to have room to stir - if thinly sliced on a mandolin, how many kilograms of onions would that be?

Or, the other way round, if one slices a kilogram of onions, how much volume would that fill?

  • just_another_person@lemmy.world
    2·
    14 days ago

    Onions don’t shrink as much, say mushrooms. This is because of their cellulose structure that holds up fairly wellonheat…for a time.

    If you cook 1 cup of onions on a high heat skillet versus a low heat skillet both for 5 minutes, the low heat volume and weight will be more. That’s because it takes high heat over time to break down the cellulose walls.

    If you’re making a gravy, you have some control and variance over how this works. If you hit them with high heat first, THEN add broth to boil them down, you’ll have less volume.

    I assume you’ll be using a flour Roux, you don’t want high heat at all because it will burn the flour mixture and give it a horrible taste.

    So let’s assume you’re doing low and slow, and you’re thinly slicing the onions and mixing everything in, you’ll expect to retain 1/2-3/4 of the volume of the onions depending on the LENGTH OF TIME it is exposed to heat.

    The longer you cook, the lesser the volume taken by the onions.

    Hope that makes sense.

    • Treczoks@lemmy.worldOP
      1·
      14 days ago

      I know how to cook that gravy, that’s not the issue. But usually, I take a “normal” pot, chuck in a few onions, and have gravy for a few servings and for the fridge. Pot space was not the issue.

      This time, I want to go big. I know that the onions shrink, so what I need to know is with how much onion I should start to get to the stated 10l limit to have enough headroom to stir the stuff.