|Low energy cooking
We are obsessive foodies, deep into
gastronomic satisfaction. The point of cooking is to produce delicious
satisfying food - its one of lifes greatest pleasures. Theres
no point in saving energy if the result tastes horrible. A microwave oven
will never produce a good roast, whatever it says on the box. Unless pasta
is fresh cooked in plentiful boiling water it will always be less than
perfect. However, there are also many ways that a cook can produce food
that tastes as good, and often better, with less time and energy.
In this section:
Fresh local ingredients
The free cook
Low temperature "boiling"
We buy all our oil, grains, pasta and fairtrade coffee from an organic
wholesaler and store them under the stairs (we put together a large bulk
order with friends). Almost all our vegetables come from a local organic
box scheme or the allotment. Occasional meat comes from local suppliers
and is either free range, organic, or from rare breeds (which is effectively
organic and far cheaper). In summer we fish for the invasive American
Signal Crayfish, which have taken over the local rivers. With nets draped
over bicycle wheels, in an hour we can pull up 4 kilos. And, of course,
we compost all kitchen waste, including paper bags.
ENERGY COOKING: THE FREE COOK
We cook casseroles and stews in an old bedside cabinet we have converted
to a "haybox" cooker. We filled it with offcuts of Celotex insulation
trimmed to tightly fit a Le Creuset casserole (it has to be cast iron).
We bring the casserole to the boil on the stove (allow 20 minutes on the
stove for meat dishes), slide it into the "cooker", fit in two extra blocks
of insulation around the pot to completely surround it, and close the
door. The residual heat cooks rice in 30 minutes and meat casseroles in
Water is a great store of heat. making it well suited for central heating.
However, like all materials that store heat well, it requires a lot of
energy to heat up; it takes as much energy to bring one saucepan of water
to the boil as it would take to heat up the amount of air in a small bedroom
from freezing to a cosy 21°C.
Then, once the water has been brought
to the point of boiling, it takes a huge additional injection of heat
to make it boil. This is called the latent heat of evaporation. Raising
the temperature just one degree from 99° to boiling requires half
as much energy again as it took to heating the water from cold. When you
next bring a pot of water to the boil notice that it seems to heat up
quite fast and then spends ages on the edge of very hot and boiling- thats
because it is accumulating the additional heat needed to boil. This is
why a watched pot seems to never boil. (At the other end of the spectrum,
it also takes a huge amount of energy to freeze water, which is why freezers
and ice makers are such energy guzzlers).
It makes no difference to cooking whether
water is at 99°C or boiling at 100°C. What is more, most food
doesnt even need water that hot. Most vegetables cook at around
90°. Meat cooks happily at any temperature over 85°C and can sometimes
taste better. Almost all germs and health nasties found in food are killed
in temperatures over 80° and the few that arent need temperatures
far higher than youd ever use to cook.
So, given all this, why does cooking
always require boiling water? In a few cases, the action of the boiling
water is an important part of the cooking. The action of the boiling helps
separate the strands of spaghetti and other pasta. In some recipes, the
food is boiled uncovered so that the cooking liquids can be concentrated
and used later. These cases are the exceptions, though. The main advantage
of boiling water to the cook is that it keeps a constant temperature.
If the water is not boiling, it is hard to know whether it is 70°
or 80° or 90°. Boiling water, though, is always exactly 100°.
It's like having a built in thermostat. If you put in more heat it will
simply boil faster. You need to lock it up in a pressure cooker for the
temperature to go higher.
Buy saucepans with lids that fit. A saucepan covered with a well
fitting lid uses a quarter less energy when boiling than a saucepan without
a lid (and the kitchen doesnt fill with steam).
Always keep the lid on the saucepan even when the water is heating
Use a saucepan that is the right size for the amount to be cooked
and use enough water to cover food by no more than half an inch
ENERGY COOKING: SIT-BOILING
Many foods can be boiled a short time, then removed from the heat and
left in the hot water to complete their cooking. This method of cooking
is advantageous from many points of view; its very low on energy
(of course) and it frees up the stove top for other purposes. But the
best argument is that many foods taste far better if theyve been
cooked a longer time at lower heat. Heavy boiling, in particular, can
be quite damaging to vegetables. What is more, in a busy kitchen with
numerous distractions, it is very easy to forget to check boiled vegetables
at a crucial time and turn around to find that they have turned to mush.
Sit-boiling allows the cook far more control over the degree of cooking.
Bring to boil, boil for the specific
time, then remove for the specified time.
|TIMES FOR SIT BOILING
||Additional boiling time
|Medium Soft Boiled egg
||Bring to boil in cold water
||Remove immediately from heat
|Large Soft Boiled egg
||Bring to boil in cold water
||Remove immediately from heat
|Old Potato (quartered)
||Bring to boil in cold salted water
|New Potatoes (small)
||Put into boiling salted water
||Bring to boil in salted water
||Bring rice to boil in double
its own volume of cold salted water
Some things can easily be cooked at the same time in the same pot - hard
boiled eggs for example can always be cooked with peas or pasta. Multi-tiered
steamers allow even more flexibility as you can add and remove different
'layers' above the pan of boiling water.
SOUP FROM BOILING WATER
Dont think waste water - think stock! The end product water from
boiled vegetables, is a rich flavoured stock that can be used as the basis
for soups and sauces. Good stock comes from lentils and pulses, potatoes,
onions, leeks, parsnips. It is best not to use
water from sweet vegetables such as peas, carrots, or from cabbage and
green leaf vegetables which can produce bitter water.
This is especially true of the water
from boiled meat. Many world cuisines have developed classic meals that
boil meat and serve it with a soup made from the boiling water. Two classic
- is a form of Chinese hot pot fondu particularly loved in Singapore
and Malaysia. A group of people sit around a cauldron of boiling water,
dunking in skewers of meat and fish. When they have finished the skewers,
they break eggs into the richly flavoured stock water and drink it as
a soup. There are many similar meat and soup combinations in Chinese
chicken soup - A chicken is boiled with root vegetables and a
few flavourings (mostly dill and pepper). The soup is served in bowls
accompanied by slices of the meat. The vegetables are usually saved
to be later mashed into hot cakes for frying. When finally stripped
of meat, the chicken bones can be boiled again for more stock.
Microwaves are bloody brilliant and every low energy cook should have
one. They are fast, extremely energy efficient, and effective. Forget
about the health scare stories- providing the door closes properly, a
microwave cooker is a lot safer than any normal high heat oven.
From a culinary point of view, though,
they are limited. Because they do not use direct heat, they cannot produce
the delicious textures or caramel flavours of high heat roasting or frying.
Their role is therefore best as a tool to supplement other forms of cooking
and performing a few particular tasks for which they are well suited:
Cooking in the
Cooking something in a saucepan on the stove
and then pouring it into a serving dish waste time, energy, and doubles
the washing up. There are several dishes that microwaves can perform
excellently in the pot.
Sauces - especially white (Bechémel
Frozen peas and beans
Heating thing up - precook vegetables and reheat at the last
minute in the microwave.
Potatoes for baked potatoes
Meat for grilling and barbecues. It is very hard to achieve the
right conditions to grill or barbecue a piece of meat so that it is
thoroughly cooked without being burnt or dried out. Not an energy saver
in this case, but a very useful health tip.