Ok, so it simmers for 3 hours but you can be doing anything else as it needs nothing from you except that you leave it to simmer in a very low heat. So try it and see how fantastic it feels to have your own home made vegetable stock, ready in the freezer, in all sizes and portions (use the silicone multi mold trays). You'll become addicted and use one whenever cooking, from a soup to a sauce to a braised meat or a risotto. Just defrost and it's ready to go, with no preservatives! I prefer the vegetable stock to chicken or meat because it has a more neutral taste and you can use it for everything. —Maria Teresa Jorge
Peel and wash carrots and cut in 3. Peel onions (red onions have a stronger flavour so if you want a more neutral taste use the blond variety). Wash the celery branches and cut off any leaves. Cut in half crosswise. Remove dark green part of leek, outer leaves and the bottom. Cut in the middle lengthwise and wash thoroughly to remove any sand and dirt. Wash the parsley and discard any yellow leaves. Wash thyme to remove dirt or dust.
Put a 7.5 quart pot with 5 quart of water over medium heat and bring to a boil.
Add all the vegetables, the herbs, peppercorns and cloves. Bring to a boil, then reduce heat to minimum and let simmer uncovered for 3 hours, until it has reduced to more or less 1/3.
Strain the stock into a beacker and allow to cool.
Clear one shelf of your freezer to be able to freeze the molds of stock.
Choose any size of silicone molds you want, the best is to make several sizes for several different purposes. Set the silicone molds on a hard base you can put in the freezer, fill the molds almost to the rim.
Freeze the stock for a minimum of one day. Remove the frozen stock from the molds and put in plastic bags, divided per size and freeze for up to 3 months.
When using the stock remember that it is quite concentrated in flavour. Allow to defrost or at room temperature or in microwave or simply put in a pan with a tablespoon of water and let defrost over very low heat.
Note: the stock has no salt so remember to season it before using.