Monday, September 24, 2007

Stock

My latest New Statesman column concerns changing your mind about ways to cook. You decide on a method, but after practising it for a while you start -- partly out of boredom and partly out of curiosity -- to question whether it really is the only or best way of working.

In Don't Sweat the Aubergine, I followed Michel Roux's advice in recommending that you cook chicken stock for two hours. Longer cooking, I claimed, would cause the flavours to grow dull. But recently I have come to suspect that the dullness of flavour comes from overcooked vegetables, and not from the meat. Longer cooking extracts more collagen from the bones, converting it into gelatin and enriching the stock. Now I simmer stock, very gently, for three and a half to four hours, adding chopped vegetables just half an hour before the end.

At the weekend, I made a kind of double stock. I poached pig's trotters, for another dish. Covering them required quite a lot of liquid, which I reduced before using it to cover the bones of a roasted chicken. I simmered this stock for three and a half hours. It was Saturday evening, and I was too lazy to add vegetables.

The stock, chilled, became a firm jelly.

I am not sure how long you should keep stock. In a recent Observer column, Nigel Slater advised that you throw it out once it starts to weep -- in other words, once bits of the jelly liquefy. The Food Standards Agency tells you to consume stock within two days. But I must admit that I have used stock that has been in the fridge for a week, with no ill effects.

4 comments:

Ferdzy said...

If I'm going to keep stock in the fridge for a week, I try to take it out once in the middle and bring it to the boil for a few minutes - it helps to make sure that it keeps that long.

Nicholas Clee said...

Ferdzy -- Researching my book, I was advised strongly against the reheating of stock. An environmental health officer told me: "Some bacteria (such as Clostridium species) are heat resistant and can survive high temperatures, only to germinate on cooling in the stock. These are toxin formers, and subsequent reheating will not denature the toxin."

Paul said...

Nicholas, would you recommend a pressure-cooker for making stock? I am considering buying one - apparently they are very popular in France and Spain, not so much in the UK - and stock would be one of the reasons for getting it.

Cheers

Paul

Nicholas Clee said...

Paul, Heston Blumenthal recommends using a pressure cooker. I tried it, and was not happy with the result.

A definite disadvantage is that your stock will turn cloudy. It's only an aesthetic flaw; but some cooks will want to clarify the liquid.

Another problem is that the pressure cooker will overcook your vegetables. I have come to the conclusion that it is best to add onions, carrots, celery and so on to a stock just half an hour before the end of cooking, so that the flavours they contribute do not grow dull.

I am in no position to be dogmatic about this, because I am sure that Heston Blumenthal cooks a better stock than I do. I prefer, though, to simmer mine slowly and gently.