Next time you need to boil vegetables again, instead of using a pan of fresh water, re-use your stock, and your vegetables will taste even better (add more water and/or salt if necessary).
Each time you repeat the operation, the richer and more flavoursome your stock will become. This doesn't only work with vegetables; you can use it to cook meat as well – which will improve your stock even further with a stronger flavour.
A few guidelines:
- If you are poaching seafood, the flavours are distinctive, so it is better to keep a separate stock on the go, rather than mix “surf” (vegetables + fish or shellfish), and “turf” (vegetables + meat).
- Even in the fridge, the stock won't keep very long, so if you do not use it within the next week to 10 days, either freeze it or boil it up again on its own.
- When you are making soup, use your stock rather than plain water (or top up with water) – you will be amazed at the difference in flavour.
- If you boil potatoes in the stock, peel them first, as the skins will do nothing for the flavour, other than add an unpleasant “earthy” taste.
- If you are making stock for the first time, you don't need to start it from scratch. Add ½ an onion (peeled) to the salted water and, if possible, a bouquet garni, or at least a handful of leek greens and a spring of thyme to give it a head start. Even better, you can start by making a more sophisticated version, a real vegetable stock.
- Don't be too quick to condemn commercially available stock cubes – they are practical and can be a good way to start a perpetual stock, especially if they are organic, but do check the label carefully to see what is in them.
To sum up: Do not throw away cooking water used to boil vegetables or poach fish or meat - this is no longer just water; it is now a delicious stock that can be perpetually reused and added to: the ultimate in kitchen recycling.
Stock (or bouillon) has long been a cornerstone of French cuisine. It is worth remembering that to the French, “bouillon” is a familiar term for a basic popular eatery. Back in the 17th and 18th centuries, in the streets of Paris and other large towns, there were little shops or stalls known as “marmites perpétuelles” (perpetual pots) where huge cauldrons containing a bouillon of vegetables and meats (mostly poultry), simmered away day and night over low fires, and from which one could buy a bowlful at any hour of the day. Each time a bowlful was served, more water was added to the pot and more vegetables and meat were added to replace what was taken out. After all those hours of slow cooking, the resulting mixed broth had a robust and quite unique flavour.
