Using liquid thrown from onions?

I'm following a method from America's Test Kitchen for caramelizing onions large batch in a crockpot. The first step is to microwave the onions and discard the liquid thrown. I'm going to make onion soup, so should I reserve this liquid? I's about 2 cups. I'm wondering if it will flavor the broth or it is not worthwhile. Now that I write this, I realize I'm just using carton beef stock, so this will only dilute the broth. But if I make from scratch in future shall I use it in place of some water?



cookbookchick April 30, 2014
If it's very water without much flavor, it might not be worth the energy expended (gas or electricity) to reduce it.
Kary O. April 30, 2014
I would totally keep it. If you don't want it to dilute the flavour you can reduce it first. Bringing it to a boil, and reducing it will concentrate any of flavour. Or, you can add it to the soup and reduce the soup (lid off) if it the flavour tastes diluted.
Meaghan F. April 30, 2014
I believe that liquid is essentially water that would have just evaporated if the onions were caramelized slowly in a pan, so you can probably ditch it. That said, try a small spoonful of the liquid while you're cooking - if it has flavor, use it; if not, discard.
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