Stoves and cooking
- Types of stoves
- Safety for all stoves
- Lighting pressure stoves
- Cooking in confined or crowded spaces
- Safety for pressure stoves
- Blowout emergency action
- Fuel economy
- Fuel containers
- Spare parts
Recent years have seen enormous changes in expectations and use of lightweight stoves for bushwalking, ski touring and camping. Most bushwalkers no longer expect to have to light a fire to cook meals when in the bush. Land managers are imposing increasing restrictions on fire use, including 'fuel stove only' areas. Today's leaders of outdoor trips should have knowledge of the variety of stoves available, what types are likely to be suitable for given circumstances, and should be able to provide practical assistance in usage where required.
Types of stoves
Stoves generally can be classified by the type of fuel that they use, and by whether the fuel is burned under pressure or not. Liquid fuels are most commonly used – solid fuel stoves are not satisfactory for longer trips. Liquid fuel stoves that operate at normal air pressure use either methylated spirits or liquid petroleum gas such as propane or butane. Liquid fuel stoves that operate under pressure use petroleum in some form, such as white spirit or white gas (often sold under the brand ‘Shellite’), kerosene or petrol. Some stoves have pumps to increase pressure, while others generate the necessary pressure as the fuel warms in a tank. These stoves can be subdivided into those with a ported burner (rather like domestic gas stoves) and those that are unported, which have a flame spreading plate, and make a loud roaring or ‘chooffing’ noise when operating.
There are advantages and disadvantages in all the different types of stoves available, and it is well worth considering these before you buy a stove. You should consider all options and all likely uses before purchase, as stoves are expensive, but with proper care will last a very long time.
Choosing a stove
The issues to consider when choosing a stove include:
- trip duration
- who will be using the stove – adults, teenagers or children
- how experienced those people are
- if the stove will be used in very cold conditions
- if the stove will be used overseas (where certain fuel types may be unavailable).
Table 29.1 compares the advantages and disadvantages of different stove types.
Safety for all stoves
Every year there are many accidents involving stoves: some minor, others very serious. Avoiding accidents means considering the following:
Stoves vary in stability, and all stoves can be unstable when used in difficult conditions. Make every effort to use your stove on a solid, horizontal surface. A small three ply wood or cork mat will help prevent it from sliding around as you stir, remove pots, etc. In the snow, mats are essential to prevent the stove melting the snow it is sitting on.
Keep stoves well away from anything that could burn or melt. Modern insulating clothing (made from artificial fibres), plastic groundsheets and nylon tent floors all burn or melt. Small sticks and dry grass burn easily. Packs can scorch or melt. Practice using your stove in the open before using it in a tent vestibule or crowded hut.
Refuelling stoves can be dangerous, especially for inexperienced group members or in crowded spaces. Let the stove cool before refilling it. Only fill in the open, outside huts and away from tents, food and other flames. Label your fuel bottle, clearly indicating what fuel it contains to avoid mistaking it for a water bottle, or filling a stove with an incorrect fuel type. Recap all fuel bottles before relighting the stove. Filling stove tanks directly from a fuel bottle can be difficult due to the small stove tank filler opening. Sigg brand bottles have fuel caps with two small holes in the thread part of the cap, designed to give some control when refilling the stove. One hole allows the fuel out while the other lets air in. The problem with this, however, is that fuel generally leaks through the threads of the partially opened cap. This can be avoided by replacing the normal bottle cap with cap incorporating a folded pouring spout, which are generally very satisfactory. You can also use a small plastic funnel.
Lighting pressure stoves (e.g. Shellite, kerosene and similar fuels burned under pressure)
There are many types of pressure stoves, and all have different procedures for lighting and use. Always read and follow the manufacturer’s instructions. Before taking a new stove on a trip, always try it at home first to familiarise yourself with its operation. Read the manufacturer’s instructions. Preferably try it out in the open, or on a level concrete floor, e.g. in the middle of an empty garage. Never bend over a stove while lighting it.
Ensure that there is adequate fuel in the tank. It is generally better to start with the tank about three-quarters full. Stoves with pumps are very sensitive to too much fuel; some air in the tank is required, or the stove is likely to flare up alarmingly.
Clearing the jet
Pressure stoves will not work if the jet is blocked. Most newer stoves have a self-pricking device which operates when the valve is turned beyond the fully open position. Alternatively, use an external pricker to ensure that the jet is clear. Carry a pricker if required, packed so as to protect the fine wire.
The lighting procedure depends on the type of stove. There are three main types:
- stoves without pumps
- stoves with pumps, but without lighting regulators (e.g. most MSR models)
- stoves with pumps, and with a lighting regulator (e.g. many Coleman and Optimus models).
Stoves without pumps
The following steps are required:
- Preheat the stove, achieved by burning a fuel in the cup below the burner. There are a number of fuelling options:
- Use an eye dropper to fill the cup below the burner about two-thirds full with fuel (methylated spirit is generally recommended, but Shellite can be used with care).
- Pour a small amount of fuel into the cup below the burner. This is quicker, but has the danger of spilling fuel.
- Use part of a solid-fuel block (e.g. metatab) in the cup below the burner.
- Use fuel from the tank of the stove. This can be done through expansion if the tank is warmed. Turn the valve one-quarter on and if fuel does not flow from the jet, wrap warm hands around the tank. When the cup is about two-thirds full, close the valve. Removing the filler cap and blowing into the tank is not recommended, as the fuel is poisonous and has a very nasty taste. There is also a chance that you may forget to replace the filler cap before igniting the stove.
- Check that the valve is closed, that the filler cap is tightly screwed down, that there is no spilt fuel and that the fuel bottle is tightly stoppered and well away from the stove.
- Ignite the fuel in the priming cup.
- Allow this fuel to almost burn out, then open the valve a small amount. The burner should immediately ignite with a blue flame.
- If the priming fuel has burnt too low and the burner does not ignite, a hissing sound of vapourised fuel flowing through the jet should be heard. Immediately ignite this with a match at the burner.
- If there is no hissing sound, either the jet has not been opened far enough, the jet is blocked, or insufficient heat has been applied to the tank. In the last case, an intermittent yellow flame may occur. Unless this flame shows immediate signs of turning blue, close the jet, allow the stove to cool a little, and begin again.
- If the jet lights with a luminous yellow flame, liquid (rather than vapourised) fuel is burning. Close the valve and then repeat the preheating procedure.
Stoves with pumps, but without lighting regulators (e.g. most MSR models)
These stoves also require preheating by burning a fuel in a cup below the burner. The procedure is as follows:
- Pump the stove with the recommended number of strokes, but note that this can be influenced by factors such as the amount of fuel in the tank, the air temperature, and whether the stove is cold or has been used recently.
- Place preheating fuel in the cup below the burner (as described above).
- Light this fuel and allow it to burn almost away.
- Open the valve.
- Light the escaping vapourised fuel at the burner, if it does not light from the preheating fuel.
- If the burner lights with a luminous yellow flame, liquid, rather than vapourised fuel is burning. Close the valve, and repeat the preheating procedure. Additional pressure may also be required.
Lighting stoves with pumps and lighting regulators (e.g. many Coleman and Optimus models)
These stoves do not require preheating by burning priming fuel, but are generally more sensitive to the number of pump strokes. The procedure is:
- Pump the recommended number of strokes.
- Open the lighting regulator to the ‘light’ position.
- Light the burner.
- When burning steadily with a bright blue flame, move the lighting regulator to the ‘run’ position.
Adjust the valve (if one is fitted) to the required position for operation.
Cooking in tents, huts, snow caves and other confined or crowded spaces
Using a stove in a confined space is dangerous, and should be avoided if at all possible. However, if there is no alternative, absolute concentration and extreme care is required. Accidents happen more easily, and more people can be injured or affected when cooking in confined spaces than when cooking in the open. As a leader, you should ensure that your group members are experienced enough with their stoves for them to be safe cooking inside. If you have any doubts about group members’ experience, you could arrange for all cooking to be done in the open, perhaps with a group shelter set up, or ask that some members cook first, while others wait to reduce crowding.
In the snow, building an open air communal kitchen from snow blocks can boost a sense of the group working together and can help you to unobtrusively assist those who need it. You can also observe what people eat to make sure that the food is adequate. This approach will also extend the time before you all move into tents for the night.
When you do have to cook inside a tent vestibule, a hut, a snow cave or other confined space, as leader you can do much to improve the safety of your group.
- Set up the area for cooking and clear away all other non-essential items, such as clothing, equipment and food.
- Designate specific areas in the hut or cave for cooking.
- Have as few people as possible near the stoves.
- Always light the stove right outside and cook with the stove either right outside, or in the vestibule.
- Most tent fabrics are highly flammable, and great care is needed if cooking in a vestibule.
- Plan ahead to keep all movements to a minimum.
- If there are children in the group, keep them well away from the stove in any confined space.,/li>
Be aware of the possibility of carbon monoxide poisoning when using stoves in poorly ventilated spaces. As leader, when your group is cooking inside tent vestibules, move among the group and check that tents are not completely closed. Carbon monoxide poisoning is insidious and tent occupants are unlikely to be aware if affected. Emphasise to everyone that stoves need constant observation and attention. Never leave a lighted stove (or a candle for that matter) unattended.
Safety for pressure stoves
There are a number of safety points that apply specifically to pressure stoves, with or without pumps.
- Avoid overheating, as this can lead to a blowout, through the safety valve.
- Always use the heat shield if one is designed for the stove.
- Take care with handles and keys, as these often get hot.
- Remove the key from the spindle if possible, after adjusting the flame. Keep billy handles out of the flame.
- Unported burner pressure stoves use a flame spreader, which should be securely in position on top of the burner directly above the jet.
- Never light a stove designed to operate with a flame spreader without it in place, as flaming fuel could shoot high up into the air.
- Ensure that the fuel tank cap is screwed down firmly. Never unscrew the cap while the stove is alight or very hot.
- Do not over pump a pressure stove — use only the specified number of strokes.
- Keep clear of the line of fire of the safety valve.
Blowout emergency action
Some pressure stoves are fitted with a safety valve built into the filler cap. If the valve blows, the escaping fuel is likely to ignite, resulting in a jet of flame which can be up to a metre long. You are then faced with a hot stove ejecting flame from two sources: the burner and the safety valve.
If a blowout occurs, immediately remove any pot from the stove, turn off the valve and then blow out the flame from the safety valve. If you cannot turn off the jet without burning yourself, you should remove the stove quickly to an open area. Do not kick or throw it outside, as it may land on another flammable object, such as a tent or a person! Extinguish the flames, by smothering with a billy, water, snow, earth etc. Provided the flames have been extinguished within a few minutes, the safety valve in the filler cap will be fit for reuse. A prolonged blowout may destroy the temper of the spring in the safety valve, and it may need replacing.
Be aware that different fuels have different thermal properties, as discussed in stove choice. Always have the billy ready for the stove, not the other way round. Learn how to cook efficiently, e.g. by presoaking and rotating billies to cook two pots at once. Do not leave a stove burning with nothing on it or ready to go on it. Minimise heat loss from the stove – always insulate the stove from cold ground or snow and use a windshield if the stove is designed for one. (Do not use a wind shield if the stove is not designed for one – it may lead to overheating of the fuel tank, and possible safety valve operation as discussed above.) Adjust the flame to suit the size of the pan and style of cooking, for example, keeping food just boiling. Always adjust pressure stoves to have a blue flame because a yellow flame makes more soot and can block the jet.
All fuel containers must be clearly marked. Red coloured bottles are commonly available, and adhesive flammable liquid labels can be obtained. There have been many instances of burn injuries caused by mistaking fuel bottles for water bottles. Make sure yours is labelled, specifying the type of fuel (do not just label it ‘fuel’, specify the type). Operating methylated spirit stoves on Shellite or kerosene, or kerosene stoves on Shellite can cause explosions and severe flare ups. Fuel bottles should be made from aluminium or tin plated steel. The washer or gasket in the filler cap should be neoprene, and not natural rubber as this perishes rapidly from contact with petroleum fuels.
Most stoves can be repaired in the field. Carry a spare jet, flame spreader and sealing rings or washers, as well as any other obvious small parts that could be lost, dropped or become perished.
Stoves are an important part of today’s bushwalking and skitouring equipment list. This importance will continue to increase with more ‘fuel stove only’ areas. If selected carefully and looked after properly, a stove can give many years’ reliable service, justifying the considerable initial outlay.