The top cooking tips that are past their sell-by date

THEY are the golden rules of cooking, from continuously stirring risotto to soaking onions to avoid tears.

But kitchen tips passed down the generations are now being debunked by scientists who have examined the chemistry behind them.

It turns out that your risotto will be perfectly creamy if you just stir it for a couple of minutes at the end, while peeling and soaking an onion will do nothing to protect your eyes.

Not only that but a piping hot tray is not essential for Yorkshire puddings and a small pan of boiling pasta is just as good as a large one.

New Scientist magazine investigated kitchen shibboleths and consulted food scientists too.

The article sheds light on the debate over whether to store tomatoes in the fridge, citing an opinion from Trevor Suslow and Marita Cantwell at the University of California, Davis, that the ideal temperature for firm, ripe tomatoes is 7 to 10C (44.6-50F).

Unfortunately a refrigerator or a kitchen do not fall within that range, but the best compromise may be to keep them in the warmer parts of the fridge, on the shelf or near the door.

And leftovers, despite most people’s beliefs, can usually go straight in the fridge. The risk of raising the temperature in the fridge, potentially putting the rest of the food at risk of bacterial growth, is dwarfed by the food poisoning danger of leaving leftovers out in a warm room, where germs can double every hour.

On risotto, Dr Matt Hartings, who teaches chemistry of cooking at the American University in Washington, said: ‘If you control your ingredients just right from the outset, a no- stir method should give you the creaminess that you’re looking for.’

Italian chefs say cooks should add pasta to a big boiling pot of water to stop it sticking together and bring it back to the boil more quickly. However science dictates that it might be quicker in a small pot, and stirring the pasta for the first minute will stop it sticking.

On Yorkshire puddings, US chef and author Kenji LopezAlt has the bravery to challenge the received wisdom on a Brit- ish classic. He said a piping hot pan makes little difference for small puddings in a muffin tin.

Instead, make sure the batter starts at room temperature to avoid cup-shaped puds.

The magazine says peeling and soaking an onion for ten minutes for chopping won’t affect the volatile chemical that makes chefs cry because it is on the inside.