A household burning wood generates a steady stream of paper and card, and turning it into fuel is an old and genuinely useful idea. It extends a wood pile, it uses something that would otherwise be waste, and it costs nothing but time.
It is also frequently oversold. Paper briquettes are a poor fuel compared with seasoned wood, they take months to dry, and no household is going to heat itself on junk mail. Treated as a supplement they are worth the effort; treated as a plan they are not.
What this is worth
Where they genuinely earn their place:
- Eking out a wood pile in a hard winter, mixed in with real wood.
- Slow overnight background burn in a stove that is not being shut down, on top of a hot bed of wood embers.
- Using something that is otherwise waste, particularly in a household with no recycling collection. See household waste with no collection.
- A useful job for a wet afternoon, and children enjoy it.
Where they do not:
- As the main fuel.
- As kindling, for which loose crumpled paper is far better.
- In an open fire, where they mostly smoke.
What to use and what not to
The method
- Tear or shred small. A garden shredder, a paper shredder, or hands and patience. Smaller pieces break down faster and press denser.
- Soak. A dustbin, a builders' bucket or an old bath, filled with water. One to two days, longer for card, until it breaks down into pulp when squeezed.
- Break it up. Stir vigorously, or use a paddle mixer on a drill if you have one. You want porridge rather than wet paper.
- Squeeze out the water, hard, by hand first.
- Press. In a mould, with as much force as you can apply. This is the step that decides whether you get a briquette or a lump.
- Turn out and dry, thoroughly, for weeks.
Warm water speeds the soaking considerably, and hot water from a stove top costs nothing if you are burning anyway.
Work outdoors or in a shed. It is wet, it drips, and pulp on a kitchen floor is unpleasant.
Presses
- A bought briquette press is a hinged steel mould with long handles, inexpensive, and it does the job well.
- Home-made: a length of drainpipe with holes drilled in it, a plunger cut to fit, and body weight or a lever. Simple and effective.
- Two buckets, one with holes drilled through the base, the other pressed down into it. The crudest version and it works.
- A bottle jack against a frame applies far more force than hands and produces much better briquettes.
- A tin can with both ends removed, packed and pushed out, for small ones.
Pressure is everything. A denser briquette burns slower, hotter and cleaner, and dries better because there is less water in it to start with. The difference between hand-squeezed and properly pressed is large.
Drainage holes in the mould let the water escape as you press, which is what makes real compression possible.
Improving them
Paper alone makes a mediocre briquette. These help considerably.
- Sawdust and fine wood shavings. The single best addition. Up to about half by volume raises the energy content noticeably and makes them burn like fuel rather than like paper. Untreated sawdust only.
- Dry leaves and small twigs, chopped.
- Straw or chopped hay.
- Wood ash, a small amount, which is said to help them hold together.
- Dried grass clippings, thoroughly dry.
- A hole through the middle, made with a dowel, dramatically improves both drying and burning by letting air through the centre.
Do not add anything oily, plastic or treated.
Drying, which is the whole difficulty
- Off the ground, on a rack or pallet, with air all round.
- Under cover but open at the sides, exactly like seasoning firewood. See split, stack and season firewood.
- Turn them regularly, every few days at first.
- Space them. Stacked touching, they will not dry.
- Sun and wind, not warmth alone. Wind does more than heat.
- A greenhouse or polytunnel is excellent for this, in summer, when it is not doing anything else.
- Bring them inside for the last week if you can, somewhere warm and airy.
How to tell they are ready:
- Light for their size. A wet briquette is noticeably heavy.
- Hard right through. Break one open and check the middle.
- A moisture meter pushed into a split face, reading under 20%, the same target as firewood.
Make them in spring and burn them the following winter. That is the realistic cycle.
Burning them
- On a hot established fire, not to start one. They are poor at catching.
- Mixed with wood, not alone. A stove running on briquettes alone burns cool and sooty.
- With plenty of air. They need it, and starving them produces smoke and tar.
- Expect a lot of ash, several times what wood produces, so the ashpan needs emptying more often.
- Never in a stove that is shut right down. See run a wood burning stove properly, whose whole argument applies with more force here.
- Sweep the flue at least annually, and more if briquettes are a regular part of the mix.
Other waste fuels
Worth knowing, with the same cautions.
- Sawdust and shavings, compressed the same way, are much better fuel than paper and are the reason to keep any woodworking waste. Untreated only.
- Dried nut shells and fruit stones burn hot and are excellent, if you have them in quantity.
- Dried corn cobs, where grown.
- Cardboard tubes and egg boxes packed with shavings and a candle stub make good firelighters. See char cloth and firelighters.
- Dried animal dung is a traditional fuel across much of the world, needs thorough drying, and is smoky. Realistic only for a household keeping livestock.
- Not household plastic, in any form, ever.