Dried beans need soaking for several hours before cooking, preferably overnight. Add a teaspoonful of bicarbonate of soda to speed things up. An even quicker method is to bring them to the boil in a pan then turn the heat off and soak them for about an hour covered. Always discard the soaking water, rinse and cook in fresh water without any salt (which toughens the skins). Allow about 55g/2oz dried weight per person. Once soaked and cooked they'll at least double in weight.