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?

Jennifer W


Lori T. June 16, 2020
I think it would probably be really difficult to do empirical studies on the precise nutritional content of homemade vegetable stock. The veggies themselves would vary slightly in content, and it could make a difference if you opted to use leftover cooking water, kitchen cooking scraps, sad refrigerator veggies, or purpose made broth from all fresh ingredients. It is possible to cook some nutrients out of the broth, particularly vitamin C- but I don't suppose you would need to be concerned unless soup were your primary source of it. I've never particularly worried about the exact nutrition levels supplied by my vegetable or meat broth, to be honest. It was always simply a means of reclaiming something that still had good use, to add flavor and whatever nutrition it could bring to the party. My own house made broth is an accumulation of scraps and cooking water, in which I simmer additions until they appear to have basically given up the ghost. I use what I have need for at that time, and freeze the rest until it is needed or wanted again. As it is constantly replenished and altered slightly- figuring out specific nutrition content would be both useless and difficult to do. I've never expected it to provide large amounts of water soluble vitamins in one go, so I wouldn't be disappointed if it didn't. I expect it is someplace between those two poles, and that's fine for my purposes. So far as the nutritional value, I would point out that "potage" kept peasants alive for centuries, as did "pot liquor" for poor Southern folks. It must have been bringing something beyond filling for a belly.
Jennifer W. June 16, 2020
I agree and those were my exact thoughts regarding pot liquor! Again, my curiosity wasnt particularly about wanting a precise nutritional breakdown of this- Simply is there any scientific backing to the thought that it is a vitamin and mineral rich food in the first place, and how one would make it to maximize this nutritional value.
Lori T. June 16, 2020
Your question actually made me curious to see what might be available as well. I figured somewhere a scientist had to have tried to figure it out as well. However, I was only able to find one study that even remotely filled the bill. I found it at https://pubmed.ncbi.nlm.nih.gov/10794612/
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.
Jennifer W. June 17, 2020
Thank you everyone for your input on this! I think what Im taking away from this is that Im going to continue making my broth because Im sure it has more vitamins and minerals than the store bought stuff at least and I know everything thats going in it:) But from now on Im going to be less reckless about how I make it- simmer it for less time and at as low a temp as possible.
gandalf June 15, 2020
Interesting question.

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.
Nancy June 15, 2020
Back to being an omnivore but spent a good chunk of my adult life as a vegetarian, and from both reading and cooking I'm with Gandalf....a closed system will retain what few nutrients you extract from the scraps or whole veg.
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.
Jennifer W. June 16, 2020
".. what few nutrients you extract.. I see the main point of homemade veg stock as flavor" you say... Hmmm really?
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.
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