A well constructed haybox can keep food temperatures well above 65 deg C after 3
hours. There are a number of factors that determine the effectiveness of a haybox.
Insulation: The thickness of the insulation is very important to the working of the
haybox cooker. If kapok, polystyrene or cork is used, this must be at least 5 cm
(2 inches) thick all round the pot. If straw, newspaper, cotton or chaff is used
as insulation then it is good to aim for a thickness of around 10 cm (4 inches).
Thickness of pot: A thicker walled pot works better than a thinner one as it retains
more heat. This will then slowly release heat while in the haybox and help cook the
food and keep it hot for longer.
Lid: It’s important to have a tight fitting lid on the pot to reduce evaporation
and heat loss. One can also wrap the pot in a towel before putting it into the haybox
– this will help keep the lid on tight. When heating the ingredients up before putting
it in the haybox make sure the lid is on the pot. This way the lid heats up to the
same temperature as the pot. Putting a cold lid on a heated pot will lower the overall
Amount of food in pot: The pot needs to be at least 3/4 full of food to ensure that
the food temperature remains above 70 deg C after 3 hours. If the pot is only a 1/4
full then after 3 hours the temperature could be as low as 55 deg C and the food
will need to be heated up before eating.
Checking on the food: Fight the temptation to keep checking the food. Every time
the lid is opened heat will escape from the pot thus slowing down the cooking process.
Just trust the cooking process and leave things to cook in the retained heat.