I work in the science behind nutrition and one of the first things you learn is that a huge amount of nutrients with your food goes down the drain when you throw out the cooking water. In the water you use to cook broccoli, chickpeas, tomato, basically any vegetable, you will find a significant fraction of the vitamis as well as some carbohydrates and fats.
I once read something about a "perpetual stew", a stew that people in the Middle Ages were keeping all year long on the fire. Whenever you needed to cook something in water, you threw it in the stew: not only it added the flavor of the stew to your meal, it also changed the taste of the stew.
I like this concept, and I was thinking that each time I cook something in boiling water, I could save that water to prevent wasting all the nutrients it contains (and likely pesticids, too, but that's another story). Keeping something on the gas at all times is a crazy ideas in this day and age, and unrealizable in my apartment. But I was thinking of buying a big jar and keeping it in the fridge at all times, fillied with the broth from whatever I cook (mostly vegetables and starchy foods, the idea of putting meat in a perpetual stew grosses me out a little bit). I would fill up the jar with the water while it's still hot, and immediately close it.
Do you think it's a good idea? Would it improve the taste of my food in addition to increase its nutritional value? And would keeping it in the fridge be enough to prevent contamination and bacterial/fungi growth?