Weigh in on A Vegetable Stock Debate
So far Google hasnt come up with any useful information on this... Id like to know How long should I simmer vegetables in order to extract the most nutrients into the broth? Is it possible to *over simmer where the broth itself will start to lose nutrients? I already read the article here on Veg Stock without a recipe, and it doesnt address this specifically. Some forums online even suggest that it is a myth that the broth has any nutritional value at all...! Thoughts?
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It's a study about the vitamins leached into water by cooking spinach- which I'd assume would be similar to collards or other greens as well. Not precisely a mixed veggie broth- but better than nothing at all. I think the main reason is because it would be so hard to do an empirical study on- there aren't exactly any control recipes out there, since everyone and their grandmother makes it slightly different every time. I do recall a study done sometime in or around 2000 involving chicken soup, and noting that people who ate it did experience less inflammation- but it wasn't a cold cure, of course. There's also the hype about bone broth- and again- no empirical proof that it does what they claim either. If you want to maximize nutritional value of veggies, of course boiling them to death in water would be the last cooking method to choose. Ideally, you would want to consume the veggies AND the cooking liquid to do that. Also, cooking temperature and time play a part if you are wishing to conserve vitamins - though not necessarily the minerals or collagen of bones. The shorter cooking time preserves that in the veggies, and lower heat conserves it better in the broth. For bone broth though, you need both time and temperature to break down the marrow, connective tissue and bone, and free up the collagen. That isn't absorbed by the body anyway- just so you know. However, digestion of it would reduce it to amino acids, which the body could use however it needed to. Honestly, I don't think there is a good answer to your question. Instead of hard scientific evidence, I think we have to just rely on the experience of grannies everywhere, and the evidence over time that veggie broth is good for us. It may not be a cure all, or even a nutritional bullet- but at least it tastes good, and it won't hurt you. Though that depends on your ingredients being organic- because there is evidence that pesticides can be concentrated in the soup liquid too. But how much and how bad it is for you remains another question entirely.
My usual practice, which I've done for a long time, is to simmer the vegetables (usually frozen) about an hour, covered, then take them off the heat and let cool for about 45 minutes or so before straining the liquid to get my stock. My focus has been on taste, not so much on nutritional content -- I assume that a vegetable stock is going to have some nutritional value.
It would seem to me that by simmering the vegetables in a covered container, I have a (mostly) closed system that will not allow much of the nutrients to escape. But I have no empirical data to support or refute that assumption.
I see the main point of homemade veg stock as flavor. Secondarily, you get a broth with no salt or much less than in commercial products.
Last, a quick scan finds a Harvard university newsletter estimating 2g protein and 4g carb from 1 cup veg broth.
I grew up being told by my Hippie Mom that we were getting good vitamins and minerals from homemade stock- the reason being the same reason we never boiled vegetables- the nutrients are leeched out into the cooking liquid. Is this outdated thinking? I too simmer lid on, but have always simmered for hours on end. Oddly, more online research makes it appear that there is no unanimous agreement as to the benefits of vegetable broth or the methods for making it.