Jane Powerson cooking
The amount of energy we use for cooking food is relatively small. For instance, a couple who use gas in the kitchen emit less than a fifth of a tonne of carbon dioxide per year when preparing their meals - roughly the same amount that would be produced if they were to fly one-way from Dublin to London.
Cooking with electricity, instead of gas, releases about twice the amount of carbon dioxide into the atmosphere (unless yours is one of the few households with "green" electricity - such as Airtricity). An induction hob, however, consumes only half the amount of electricity as a conventional one, so the emissions are halved also. Nonetheless, induction hobs are expensive, and function only with cookware that responds to magnetism. Aluminium, copper and some stainless steel pots and pans are not suitable, so the cost (environmental and financial) of new cookware may need to be factored in.
For reheating food, a microwave is more energy-efficient than a gas or electric oven. The few minutes that it takes to "nuke" yesterday's dinner create far less carbon dioxide than 20 or 30 minutes in an oven.
Perhaps the least efficient way of cooking - although one of the most comforting - is with an Aga. Pumping fuel into a cast iron behemoth that does not even run the central heating is not particularly kind to the environment. The company, however, is working on new models, including some with condensing boilers.
A few simple tips, as practised by our mammies and grannies when trying to keep their household bills down, could also help to curb our greenhouse gas emissions today. When cooking on the hob, choose the smallest pan possible for the job, and a burner that matches the pan size (a larger burner wastes heat); put the lid on if you're boiling or simmering. A pressure cooker cuts cooking time by about half, and is especially useful for foods that take a long time, such as pulses and stocks. If you have a freezer, it is more efficient to fill it than have it half empty, so cook double or treble quantities whenever possible. Don't bother preheating the oven for casseroles and the like - but do if you are baking. And leave the oven door closed when it's on: every time you peek, you lose up to 20 per cent of the heat.
u planetmatters@irish-times.ie