Don't Sweat the Aubergine

cook, and if you’re not planning to show off to your friends by producing a translucent consommé, probably not. This stuff won’t do you any harm. If you’re a chef, you may want to cook your stock uncovered, with the merest blip showing on the surface of the liquid from time to time; and even after that you may need to clarify the liquid with egg whites. (You whip the egg whites, add them to reheated stock, and discard them once the impurities have adhered to them.)
    I cover the pot, even though the build-up of steam under the lid causes quite vigorous bubbling. I do so for the sake of simplicity, knowing that I can leave the stock without worrying too much about evaporation, and also that I am ensuring the maximum possible conversion of collagen to gelatine (see the next point).
    3 • Cooking time . I don’t think that any other preparation is the subject of such variations of advice about cooking times. ‘Eight hours with the water steaming but not bubbling will reward you with a jewel-bright, flavour-packed consommé,’ Richard Whittington writes in
Home Food
. Other writers do not go quite so far, but usually agree that long cooking is good. But Michel Roux advises a one-and-a-half-hour simmer, asserting that ‘long cooking can be detrimental’. Most radical is Shaun Hill, who in
How To Cook Better
advises a simmering time of 40 minutes.
    Simmering the meat and bones extracts flavour and converts collagen – a protein from the bones, skin and connective tissue – into gelatine. A satisfying stock will set to a jelly in the fridge, and will have a wonderfully rich and unctuous quality. To achieve this result, you need to simmer the bones in particular for a while – I usually allow 3 to 4 hours. Collagen begins to convert to gelatine at 70°C, so you can cook the stock uncovered at a temperature below boiling point, if you like; but a slightly higher temperature, which you get in a covered pan, will convert the collagen from the bones more efficiently.
    4 • Don’t overcook the vegetables . The drab quality of some stocks comes, in my view, from overcooked vegetables rather than from overcooked meat. The flavour from carrots and green things seems to grow stale after a certain point – this is worth remembering when you make soups, too. Onions do not cause this problem, and won’t do any harm if added to the pot at the beginning. But keeping them in the pot for longer than the time necessary to extract their flavour won’t bring any benefit, either.
    5 • Rapid chilling . The Food Standards Agency advises that you cool stocks within 2 hours and consume them within 2 days, or that you conserve them in the freezer (ice trays are useful containers). I must admit that I am not scrupulous in following this advice, allowing my stock to cool in the pot before straining and refrigerating it, and keeping it for up to a week. I reckon that, as long as my stock still smells fine, and even though the jelly may have collapsed a little, it probably won’t do me much harm. So far, so good. But I should tell you to do as I write, not as I do.
    Don’t put a hot container in the fridge. It will raise the temperature, and cause condensation.
    Don’t reheat stock more than once, the FSA adds. There may be some bacteria that will resist the rise in temperature; and, as the stock cools again, they will multiply.
    6 • Deglazing . This is a term you’ll come across a lot in descriptions of the making of gravies and sauces. As meat browns, it undergoes what are known as Maillard reactions – chemical changes that produce a great deal of flavour. The flavoursome residues of those reactions stick to the bottom of pans in which you have roasted or fried meat. You can incorporate that flavour in sauces by reheating the pan and adding liquid – water, wine or other alcohol, cream ; the liquid will release the residue, which will dissolve as you stir. In the case of your roasted chicken wings, remove them to the stockpot, and put the roasting dish on to a medium heat; add water, and scrape and stir with a wooden spoon until you’ve lifted all the residues. Pour the liquid into the stockpot. If there are still bits of chicken left in the roasting dish, repeat the process.
    A note about nutritional value. Stock ‘has no food value apart from some minerals’, Good Housekeeping (
The New Cookery Encyclopedia
) asserts. But, as we’ve already seen, it has the protein gelatine, and probably some remaining collagen