The Solar Cooker

The solar cooker I use is a Sunstove, available from Margaret Bennett . e mail at sunstove@iafrica.com.



This method of cooking is the only one which is totally free. It is extremely easy. Place the food in a black pot, place in the solar cooker which is facing the sun or facing north if you are going to leave it for a long time.
The Sunstove comes with a pot and an instruction booklet, including recipes. It is ideal for one pot cooking, stews, vegetables, rice, pap, mince dishes. It is not suitable for dishes requiring rapid boiling, eg pasta, frying or baking (except meringues)
A black pot is preferable, but not essential. The sunstove cooks even if there is only 30 minutes of sun per hour. Food needs to be put in the sun before 10am as that is the best time for cooking. It is also possible to place the food in the sun before work and leave the sunstove facing north. It will be ready by 2pm but still warm by 4pm. It might just need a bit of reheating later in the day.
Advantage of a solar cooker

1. Free energy
2. It is light and so portable and can be moved to where the sun is, or taken camping etc.
3. It is almost impossible to burn food.

Disadvantages of a solar cooker

1. The cooker only works when there is enough sunlight, therefore not at night and not in the rain. It cannot be used as the only source of cooking. It can only be an additional source of cooking and will always require a back-up. However, when it can be used it saves electricity or wood or other fuel.
2. Food left unattended for long periods can be stolen. (Of course if there are grannies in the community they can sit near all the solar cookers and guard the food and cookers)

General Guidelines

1. The sunstove is designed for a family of 4. It can take more than one pot but if cooking for a larger number of people it will be necessary to use more cookers.
2. For cooking fresh vegetables it is not necessary to add water. Food will cook in its own juice.
3. Food must be placed in the sun before 10am in the morning for best results.
4. (From Sunstove 2000 Booklet)(2)

a) You will need twice the normal cooking time or a bit longer
b) Stews and casseroles use less water.”
g) food will cook quicker in 2 smaller pots than one big one. Don’t leave a lot of airspace above your food.”

1. The pots will get extremely hot and the use of a pot holder or oven gloves is necessary for removing the pot from the solar cooker.

Temperatures reached by the Sun stove

Dec 29 2009                                    

Partly cloudy, Max 26°C                         
Time           Temp °C                                                                           

9.00	40
9.30	50
10.10	90
10.55	120
11.20	120
12.00	120

These were my two extremes. When there was 50% cloud cover the stove reached a maximum of 95°C, 25% cloud cover it reached a maximum of 110°C. Cooking with more than 50% cloud was not very successful and another source had to be used to complete the cooking.

Make your own hot box

You will need: A square box or container at least 5 cm larger than your pot on all sides, 2-3 metres fabric, newspaper, small pieces of polystyrene as used in packing.
Method: Take the following measurements: diameter of pot = a, height of pot = b, Height of box = c , side of box = d.
Cut out 2 squares of newspaper, one with sides of a, one with sides of d. Fold them both diagonally in quarters and cut out one quarter of each.
On a large sheet of newspaper cut out the following pattern.   Add 1,5 cm all around for seams.   Using the newspaper pattern, cut 4 identical pieces from the fabric.

Sew all 4 pieces together, right sides together , leaving one diagonal open. Turn right side out. Half fill the cushion with the polystyrene and then close up the opening. Arrange the cushion in the box with the base (d) downwards. Form the narrow top part into a nest inside the cushion. It should be just big enough for your largest pot. Make another cushion for the lid out of two square pieces of material the length of the base of the box. Fill with the polystyrene. Alternatively you could use a pillow as the lid.

The Hot Box

In days gone by farmers’ wives knew that if you heated up porridge to boiling point for five minutes before bed, it would continue cooking if the pot was placed in a box and completely surrounded by hay. The next morning there would be a
warm breakfast. They called it a Hay Box. This is the basis of the Hot Box, also sometimes known as the Wonder Box. It relies on the principle of insulation. Food heated through for five or ten minutes and then well insulated, will continue
to cook as the heat is kept in.
At the simplest, place the pot on a dish cloth on the middle of a blanket. Fold the blanket around and over the pot and put it in a corner out of the way. The Wonder Box consisted of a specially shaped cushion inside a box and was  marketed by various charities. Any good insulation can be used in a Hot Box, even balls of crumpled up newspaper.
How to use a Hot Box for cooking.
Use the smallest pot that will take the amount of food you are cooking. The fuller the pot , the more efficient the cooking. Any source of heating can be used:- open fire, biogel stove, gas, paraffin or electricity. Heat the food and
enough water in the pot with the lid on and allow to boil for 5 or 10 minutes. Switch off the heat and place the pot upright in the box so that it is surrounded by the insulation or cushion. Leave for the appropriate amount of time (at least one and a half hours but it will continue to stay hot for up to 10 hours).

Recipes

Rice
Boil 2 cups of water and 1tsp salt and a stock cube. Add one cup of rice and allow to boil for another 5 minutes with the lid on but allowing a small gap for steam to escape. Place in Hot Box for an hour and a half.

Mielie meal
Use the quantities of meal and water you would normally use for the consistency you require. Boil for 5 minutes and then keep in the Hot Box for at least an hour or until required.
Chicken and Lentil soup
Add 4 cups of water to a chicken carcass, 1 tsp salt, 1 chicken stock cube, 1 cup lentils, a chopped onion, chopped or grated carrot or any vegetables of your choice. Boil for ten minutes then place in Hot Box for at least 2 hours. Can start
it before work and come back for supper. Remove the bones, scraping off any chicken still adhering to them. Liquidise if you prefer a smoother soup.

Foods that can be cooked in a Hot Box
The Hot Box is ideal for foods that cook slowly. It is excellent for rice, stews, one pot meals, dried legumes, vegetables,
mealie meal, soups. It works well at keeping most things hot and is ideal for transporting a hot dish for eating with friends. It is not suitable for foods that need brisk boiling like pasta.

Simple ways to save power.

We are all aware of the fact that the pot or pan is not hot enough as soon as we switch the hot plate on. It takes a little while for the plate and pot to heat up. In the same way, it takes a little while for them to cool down so if we switch off the power about 5 minutes before the food is cooked, it will still continue cooking in the hot pot on the hot plate.
· Use the kettle sparingly. A kettle is rated at about 2 kilowatts. Boil only enough water for your needs. If you are making one cup of coffee, boil one cup of water. This reduces the amount of time the appliance is working. Another option is to use a thermos flask or pump pot. Boil a full kettle and then pour any unused boiling water into the pump pot. For the next two hours you can use the water for making coffee or if you need it really boiling for tea, pour it back into the kettle and it will take much less energy to heat it up the last couple of degrees.
· Use the microwave instead of the hot plate as often as possible. Most food cooks faster in a microwave.
· Other options are a pressure cooker (which cooks faster because the high pressure enables the temperature to get much higher) an electric frying pan or steamer, where different foods can cook at the same time by stacking up on top of one another.
· On an electric stove top, use pots and pans with flat bottoms to maximize surface area and use a hot plate the same size as the pot.
· If you have to use the oven, make sure the seals fit properly to reduce heat loss. Test by closing a piece of paper between the door and the oven. If the paper slips out, you could be losing a lot of heat. Replace the seal to avoid wasting energy and money.
· Cook more than one dish in the oven at a time or one pot dishes on a stove top.
· Consider cooking in bulk and freezing, using the microwave to heat the dish.
· Thaw food overnight in the fridge rather than in the microwave.
· Keep the lid on when possible to reduce heat loss
· Dishes requiring browning in an oven eg macaroni and cheese use a lot of electricity just to get the cheese topping browned. Five minutes under a TV grill will give the same result with far less energy consumption.









Macaroni Cheese browned under a TV grill

• It costs almost the same to buy a roast chicken from most supermarkets as a fresh one. You save not only the electricity that you would use to cook it, but also the human energy you would use.
• Use insulation. We are so used to the concept of warming up food quickly in a microwave that we no longer try to keep it hot. Any insulating material wrapped around a pot or dish will help keep it hotter for longer. Examples are – newspaper, corrugated cardboard, blankets, packaging materials. The Wonderbox is an example of how food can not only be kept warm but continue to cook without the use of any electricity at all.