Drying wet clothing and gear – on the move and at home

For water to evaporate it needs energy – that is, heat. It takes this heat from its surroundings: from the sun, from the air or, if you are wearing wet things, from your body. That is why wet clothing feels so cold in the wind. Water also conducts heat much better than air; a wet fabric hardly keeps you warm any more, because the insulating air spaces between the fibres are filled with water.

Air can only take up a limited amount of water vapour, and cold air less than warm air. If the air around a garment is already damp, hardly anything evaporates. Wind constantly swaps this damp layer of air for fresh, drier air. That is why laundry often dries faster on a windy day than on a still one, even if it is no warmer.

The third lever is the amount of water. Whatever you press out beforehand no longer has to evaporate. And the larger the exposed surface, the more water can escape at once – a shirt spread out dries much faster than a crumpled one.

First the water comes out: wring firmly, then roll the item in a dry towel or cloth and press hard or kneel on it. The towel soaks up a lot of moisture that would otherwise have to evaporate slowly. With wool and delicate fabrics, press rather than twist hard.

Then stretch a cord between two points in the wind and, if possible, in the sun. Hang things spread out and spaced apart so air can flow between them. Safety pins hold them in place when it is windy. On a trip, it pays to spread tent, sleeping bag and pad out in sun and wind at every break.

The material makes a big difference. Thin synthetics dry quickly, wool still keeps you somewhat warm when damp, cotton soaks up water and dries very slowly. Down loses much of its insulation when wet and dries only very slowly – so with a down sleeping bag the main thing is to keep it dry rather than having to dry it later.

You can dry a thin, only slightly damp layer on your body: under a windproof jacket while walking, from your own body heat. But this only works if you are warm enough and moving. In the cold it is better to swap wet things for dry ones, if you have any.

Small items such as socks or gloves can go into the sleeping bag with you overnight in a bag so they do not freeze. They rarely become fully dry there, but in the morning they are not frozen stiff. What matters is that the sleeping bag itself stays dry – hence the bag.

Never leave wet things crumpled in the backpack and do not stuff a wet down sleeping bag into its stuff sack. Both trap the moisture and can turn musty. In long spells of rain: dry spare clothing in a waterproof bag cannot be replaced by anything.

If the power is off or there is no dryer, it is best to dry laundry in the warmest room on a rack, with space between the items. When the weather allows, drying outdoors is even better, because then the moisture never gets into the home at all.

Wet laundry releases a lot of water into the room air. So air the room several times a day briefly and thoroughly with the window wide open, rather than leaving it permanently tilted open. Otherwise the moisture condenses on cold walls and window corners and mould can grow.

Do not put clothing on heaters, and never use barbecues, camping stoves or heaters that are not designed for indoor use to dry things. They can start fires and release carbon monoxide, a poisonous gas you cannot smell.

Fire is the biggest risk when drying things. Clothing never goes over stoves, candles, radiant heaters or embers and is never left drying unattended by a fire. Synthetic fibres melt and can stick to the skin; other fabrics catch fire. Inside a tent, no heat sources are used for drying. And a down sleeping bag never goes directly next to a heat source.

Cold is the second risk. Wet clothing can chill the body quickly, especially in wind. Shivering, clumsiness, confusion or great tiredness can be signs of hypothermia. Take them seriously: get out of wind and wet, put on dry clothes, wrap up warmly and get help – the local emergency number (112 in the EU).

How long something takes to dry depends on material, temperature, humidity and wind; no fixed times can be given. So always plan as if it will take longer than you think – and make sure you always have at least one dry layer.