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Fire, cooking and heat

Start fire without matches, build efficient stoves, cook, heat a room and make charcoal.

1 Basics

Fire needs three things: heat, fuel, air

Almost every failed fire is too little preparation: wet fuel, too few thin sticks, or the fire smothered with big wood too early.

HEAT FUEL OXYGEN (AIR) spark, flame, friction, sun gaps between sticks, wind
Remove any side and the fire goes out. That is also how you put one out: water removes heat, sand or a lid removes air, clearing the ground removes fuel.

Tinder, kindling, fuel

StageSizeGood sourcesHow much
TinderHair-thin fibresBirch bark (burns even damp), dry grass, cattail fluff, old man's beard lichen, wood shavings, cotton wool with petroleum jelly, char cloth, fatwood scrapingsTwo big handfuls, fist-sized nest
Small kindlingMatchstick to pencil leadDead twigs that snap cleanly, still on the tree (not on the ground), feather sticksTwo big handfuls
KindlingPencil to thumbDead standing branches, split dry woodAn armful
FuelWrist and upSplit logs, dead standing wood; split wet wood to reach the dry coreThree times what you think
The snap test

A dead twig that snaps with a crack is dry enough. One that bends is wet or alive. Gather everything, sorted by size, before you strike anything.

Fire in the wet

  • Get off the wet ground: a platform of wrist-thick sticks laid side by side.
  • Look for dry wood inside: dead branches under dense conifers, the core of split logs, resin-soaked pine stumps (fatwood, smells of turpentine, lights when wet).
  • Carve feather sticks: shave thin curls down a split stick, leaving them attached. Three or four replace tinder.
  • Birch bark contains oils and burns in rain. Peel only loose outer bark from dead or fallen birches.
  • Build a lean-to over the fire site with bark or a tarp until the fire is established.

2 Ignition

Starting fire without matches

Stock the easy methods now. Friction methods work, but take practice, energy and perfect wood.

MethodReliabilityNeedsNotes
Disposable lighterVery highNothingThousands of lights each. Buy 20. Warm in a pocket in frost. Works as a spark wheel when empty.
Stormproof matchesVery highDry boxKeep in a sealed jar with a striker strip.
Ferro rodHighFine tinderThousands of strikes, works wet. See below.
Battery + steel woolHighFine steel wool (0000), 9 V or 2 × AAInstant ember.
Magnifying lens / reading glassesSun onlyChar cloth or dark tinderAlso a clear plastic bag of water or a polished can base.
Flint and steelMediumHigh-carbon steel, char clothOld file or carbon steel knife spine and a sharp flint or quartz edge.
Bow drillLow–mediumRight wood, cord, practiceThe best friction method. See below.

Ferro rod

  1. Prepare fine tinder

    Fluffed-up dry grass, cotton wool with petroleum jelly, birch bark scraped into powder, or the scrapings of fatwood.

  2. Put the rod in the tinder

    Tip of the rod touching the tinder, striker (knife spine, steel scraper) held still at a steep angle.

  3. Pull the rod back, not the striker forward

    Keep the striker still and pull the rod towards you. The sparks land in the tinder instead of scattering it.

  4. Feed small kindling immediately

    Tinder burns for seconds. Have matchstick-thin twigs in hand.

Battery and steel wool

Pull a pad of fine steel wool (grade 0000 or 000) into a loose fluffy strip. Touch both terminals of a 9 V battery to it, or bridge the two ends of a pair of AA cells held in line. The fine strands glow red and spread. Drop it into a tinder nest and blow gently. Works in wind, even with slightly damp wool. Keep battery and wool in separate bags, because they can ignite by themselves in a pocket.

Char cloth

Char cloth catches the weakest spark or sunbeam. Cut 100% cotton (old jeans, T-shirt) into squares, put them in a metal tin with a nail hole in the lid, and set it in a fire. Smoke and flame jet from the hole. When it stops, take the tin out and let it cool closed before opening, or the cloth burns away. It should be black and flexible, not brown or crumbling. The same works with punky rotten wood, cattail heads and the fungus Fomes fomentarius (hoof fungus). King Alfred's cakes (Daldinia, black balls on dead ash) take a spark straight from the tree once dried.

Bow drill

Bow drill in four steps

fireboard, notch 1/8 of circle leaf or bark catches the dust foot on board bearing block (hand) bow: long, even strokes smoke: speed up ember into tinder nest, fold it over, blow gently
  1. Burn a socket into the board with a few strokes, then saw a V-notch from the edge to the centre of the socket. Put a leaf under it.
  2. Kneel with one foot on the board. Loop the spindle into the string, press down with the bearing block, bow in long, full strokes.
  3. Once it smokes, speed up and press harder for 20–30 more strokes. The notch fills with dark brown, fine dust.
  4. Rest the spindle, tap the board away. The smoking dust is the ember: tip it into a nest of fine tinder and blow until it flames.

Wood

Dry, dead, soft enough to dent with a thumbnail: lime (basswood), willow, poplar, aspen, hazel, sycamore, ivy, cedar, elder stem. Same wood for spindle and board is easiest.

Sizes

Spindle thumb-thick, straight, about 20 cm, pointed top, blunt bottom. Board 2 cm thick. Bow is a stiff stick the length of your arm, cord slightly slack.

Bearing block

Hardwood with a dent, a stone with a hollow, or a bottle base. Lubricate with leaf, grease or ear wax so the top does not burn too.

If it only squeals

Glazed shiny surfaces: roughen with sand or grit. Too hard or damp wood. Notch too small. Not enough downward pressure.

Sun and lens

Any convex lens works: magnifier, reading glasses (long-sightedness), binocular or camera lens, a clear bottle or bag full of water, a clear ice lens polished with warm hands. Focus to the smallest, brightest point on something dark (char cloth, black-marked paper, punky wood, dry dung). A polished can base or a car headlight reflector also concentrates the sun. Only works in direct sun, roughly 10:00–15:00.

3 Build

Fire lays: which shape for which job

The shape decides how fast it burns, how much smoke it makes and how easy it is to cook on.

tinder + kindling burns downwards big logs each layer crosswise
Top-down (upside-down) fire: light it once and leave it. Little smoke, burns for hours, forms a bed of embers for cooking. Best for stoves and long burns.

Teepee

Kindling leaned in a cone over tinder. Fastest to catch and hottest, burns out fast. Use to get going and to boil quickly.

Log cabin

Pairs of sticks stacked crosswise around a small teepee. Stable, good airflow, collapses into an even bed of coals for cooking.

Lean-to

Kindling leaned against a large log on the windward side. Shields the start from wind and rain.

Star fire

Five or six logs meeting in the centre like spokes. Push them in as they burn. Saves wood, easy to keep small overnight.

Long fire

Two green logs side by side, fire between. Pots rest on the logs. A long fire along a shelter entrance warms a sleeping person.

Dakota hole

A pit 30 cm deep with a second hole joined at the bottom for air on the windward side. Little smoke, hard to see, burns hot, works in wind.

Reflector

A wall of stacked logs or rock behind the fire throws heat back at you. Sit between the fire and a second reflector (a rock face, a tarp) and you are heated from both sides. Never use wet river stones next to a fire: trapped water can make them burst.

4 Stoves

Rocket stove: cook on a handful of sticks

An insulated L-shaped tube. Draught pulls air through the fuel, the fire burns hot and clean, and most of the heat goes into the pot. Uses a fraction of the wood of an open fire.

pot on spacers: gap ≈ 1–2 cm chimney 2–3 × taller than feed insulation: ash, sand + clay, perlite, vermiculite feed: sticks slide in shelf: fuel above, air below → cold air in
All tubes the same cross-section. The chimney must be insulated, otherwise it absorbs heat, the draught dies and it smokes.
  1. Tube

    Quickest: a large tin (paint tin, 5 L oil can) with a smaller tin or pipe inside, joined by an elbow or a hole cut in the side near the bottom. Or 16–20 bricks laid in an L without mortar. Or a stovepipe elbow.

  2. Insulate

    Fill around the chimney with wood ash, perlite, vermiculite, crushed pumice or a sand and clay mix. Not plain soil or concrete: they soak up heat.

  3. Shelf

    A piece of sheet metal or a grate in the feed so air enters under the sticks.

  4. Pot supports

    Three bolts, stones or a folded strip of metal so hot gas can escape along the pot base. A skirt of sheet metal around the pot with a 1–2 cm gap boosts efficiency further.

  5. Burn

    Light a bit of paper in the elbow, feed thumb-thick dry sticks, push them in as the tips burn. Add only a few at a time: too much fuel means smoke.

Other small stoves
  • Hobo stove: a large tin with air holes at the bottom and a feed door. Quick, less efficient.
  • Wood-gas (gasifier) stove: a tin inside a tin, holes at the bottom of the outer and top of the inner. Fill with pellets or wood chips, light from the top. Burns smoke-free and leaves charcoal.
  • Alcohol stove from two can bottoms for methylated spirits or bioethanol: silent, indoors-safe for short cooking with ventilation.

5 Cook

Cooking with the least fuel

Fuel becomes precious fast. Every litre of water boiled costs wood that someone had to cut, dry and carry.

Lid on

A lid cuts cooking energy by roughly a third. Use the smallest pot that fits and as little water as possible.

Soak first

Beans, lentils, grains and rice soaked overnight cook in half the time.

Coals, not flames

Cook over glowing coals for even heat. Flames blacken pots and burn food on the outside.

One pot

Stews and soups use one fire. Put the kettle for washing water on the stove as soon as the meal comes off.

Haybox (retained-heat cooker)

Bring the food to a full boil, simmer briefly, then put the pot with its lid into an insulated box and let it finish on its own heat. Saves 50–70% of fuel and nothing burns.

Box: a crate, cool box or cardboard box lined 8–10 cm thick all round with hay, straw, blankets, pillows, wool, polystyrene or crumpled newspaper. The pot should fit snugly, with a cushion pressed on top.

FoodBoil firstThen in the box
Rice5 min1–1.5 h
Potatoes5 min1–2 h
Porridge oats, barley5 min1–2 h / overnight
Lentils10 min2–3 h
Beans (soaked)10 min hard boil3–5 h, reboil if not soft
Stew with meat15 min3–5 h
Danger

Kidney and other dried beans contain a toxin (lectin) that is only destroyed by at least 10 minutes of vigorous boiling. Slow, low-temperature cooking makes it worse. Food that has cooled below 60 °C must be eaten or reboiled within a few hours; do not leave it in the box overnight and eat it cold.

Solar cooker

A box painted black inside, with a glass or clear plastic lid and foil reflectors around it, reaches 90–150 °C in full summer sun. Dark pot with lid. Slow (2–4 h), free, and good for pasteurising water (65 °C for 6 min kills most pathogens; see making water safe). Useless in winter at northern latitudes.

6 Heat

Heating a home with wood

A stove in a closed firebox is four to five times more efficient than an open fireplace, which can even cool the house by sucking warm air up the chimney.

Carbon monoxide kills silently

Never burn charcoal, run a barbecue, camp stove, patio gas heater or generator in a house, tent, garage or car. CO has no smell. Symptoms: headache, dizziness, nausea, tiredness, confusion; several people or pets ill at once in the same room. Get everyone into fresh air immediately.

Fit a battery CO alarm in every room with a flame and where people sleep. Keep a smoke alarm too. Stock spare batteries.

Running a wood stove

  • Burn hot and bright, then turn the air down a little. A smouldering fire with the air shut makes tar (creosote) that lines the chimney and can catch fire.
  • Top-down lay in the stove: fewer lightings, less smoke.
  • Add a few logs often rather than filling it once.
  • Look at the chimney outside: clear air or white steam is good. Grey or brown smoke means wet wood or too little air.
  • Sweep the chimney at least once a year, twice with heavy use. A brush on rods or a weighted brush on a rope from the roof.
  • Chimney fire (roaring noise, flames from the top): shut all air to the stove, call help, get out, wet the roof near the chimney. Do not throw water into a hot stove.
  • Keep a metal bucket for ashes with a lid; ashes stay hot for days. Ash is good fertiliser and a scouring powder.

Firewood

Fresh wood is about half water. Burning it wastes much of its energy boiling off that water and clogs the chimney. Seasoned wood below 20% moisture gives roughly twice the heat of fresh wood.

  1. Cut and split early

    Winter or spring for the winter after next. Split logs dry many times faster than rounds.

  2. Stack off the ground, in wind

    On pallets or rails, bark up, in the sun and wind, gaps between rows.

  3. Cover only the top

    Sides open so wind passes through. A tarp wrapped all round traps moisture.

  4. Wait

    Softwood and birch: about 1 year. Beech, ash: 1–2 years. Oak: 2 years. Dry wood is lighter, has cracks in the ends and knocks with a clear sound.

WoodHeat per stacked m³ (dry, approx.)Notes
Oak, beech, hornbeam~1,900 kWhBest. Long, steady burn, good coals. Slow to dry.
Ash~1,800 kWhExcellent, dries fastest of the hardwoods.
Birch~1,600 kWhGood, lights easily, burns fast. Bark is a great fire starter.
Pine, larch~1,400 kWhHot, fast, sparks. Fine in a closed stove if dry.
Spruce, fir~1,200 kWhKindling, sparks a lot on open fires.
Alder, willow, poplar~1,000–1,300 kWhLow heat, burns fast. Better than nothing.
How much

One stacked cubic metre of dry hardwood holds about the same energy as 190 L of heating oil. A poorly insulated house can burn 15–25 m³ in a central European winter; heating one well-insulated room takes 3–6 m³. Insulate before you cut: see one warm room and insulation. Estimate your need with the calculators.

Cutting it safely

  • A bow saw and a splitting maul work forever with a file and no fuel. A chainsaw is far faster but needs fuel, chain oil, spare chains and protective trousers.
  • Split on a chopping block at knee height, feet apart, never with someone within two axe lengths.
  • Dead standing trees (especially ash, birch, spruce) can snap unpredictably. Felling is a skilled job: learn from someone before you try.

7 Charcoal

Making charcoal: the barrel retort

Charcoal burns hotter than wood, smokeless and light to carry. You need it for forging and smelting, water filters, and it is a good cooking fuel.

Tin-in-a-fire retort

tin packed tight with dry wood small holes, facing down fire built all around the tin wood gas jets out of the holes and burns jets stopped: done cool closed, ~70% smaller
  1. Pack a metal tin or small barrel tightly with dry wood pieces. Close the lid. A few small holes (5–8 mm) in the lid or base, facing down.
  2. Build a fire all around it and keep it hot.
  3. After a while, gas hisses from the holes and burns as small jets. This heats the tin further. Keep going until the jets stop (1–3 h for a paint tin).
  4. Pull the tin out, seal the holes with mud and let it cool completely, overnight, before opening. Air on hot charcoal makes ash.

Yield

About a quarter of the dry wood's weight becomes charcoal. Any wood works; hardwood gives denser charcoal.

Bigger batches

A 200 L drum inside a larger drum or a pit with the gas piped back into the fire. The earth-covered clamp (traditional charcoal mound) works without metal but takes days and constant watching.

Uses

Forge and blacksmithing, cooking outdoors, water filter layer, biochar for soil (crush, soak in urine or compost, dig in), activated charcoal for poisoning (needs high-temperature steam treatment).

Danger

Charcoal gives off large amounts of carbon monoxide and no warning smoke. Only ever burn it outdoors. Store fresh charcoal a few days in the open before bagging, as it can reignite on its own.

8 Safety

Fire safety when nobody comes

With no fire brigade, one house fire can destroy everything you have stored. Prevention is the only option.

Every fire, every day

Burns

Cool with running or clean cool water for 20 minutes, cover loosely with cling film or a clean cloth. See Medical.

Clothes on fire

Stop, drop to the ground, cover the face, roll. Smother with a blanket or coat.

Pan fire

Lid or damp cloth over it, heat off. Never water on burning fat or oil.