I remember watching a Nigella programme where she soaked chickpeas, I think with some bicarbonate of soda. I wanted to check if this is correct and what was the purpose of the bicarb?
Most pulses, such as dried beans and chickpeas, need to be soaked before cooking. If you are using dried chickpeas then you should soak them overnight in plently of cold water, or use the quick method where the pulses are covered with water, brought to the boil, taken off the heat and left to soak for an hour. Bicarbonate of soda (baking soda) can be added to the soaking water (after boiling, if using the quick method) as it helps to soften the skins of the pulses, making it easier for the dried pulses to absorb some of the soaking water and helping them to rehydrate and soften. This can be useful for older pulses which tend to need more soaking and longer cooking. You could try using 1 teaspoon of bicarboante of soda per 1 lire (1 quart) of water.
The pulses should be thoroughly rinsed after soaking and placed in a saucepan of fresh water. Bring them to the boil and keep at a boil for 10 minutes before reducing the heat to a simmer. This boiling time is needed to kill off toxins which can be present in some pulses. We would not recommend using bicarbonate of soda in the cooking water as it can cause the pulses to become too soft or mushy and can sometimes leave a soapy taste.
If you are cooking pulses then it is better to add salt and acidic ingredients, such as tomatoes, once the pulses have softened sufficiently. Salt and acids tend to toughen pulses so if they are added too early then the pulses will remain firm no matter how long they are cooked for.