Wood charcoal is expensive and puts pressure on forests. Charcoal briquettes made from farm and sawmill waste are one way to reduce both problems. They are simple to make at small scale, which is why they are popular with community groups and small businesses.

Step 1: Choose your feedstock

Many waste streams work: sawdust, coconut husks, maize cobs, rice husks, bagasse, coffee husks and groundnut shells. Use dry, clean material. Avoid plastics, treated timber and anything chemical. You can also use charcoal dust and small pieces left over at charcoal sellers, which saves a carbonisation step.

Step 2: Carbonise the waste

Carbonising means heating the waste with very little oxygen so that it turns into charcoal instead of burning to ash. Small-scale producers often use a sealed drum or a purpose-built kiln. Work outdoors, keep people and animals away, and let the charcoal cool completely before opening the kiln. Check local rules on smoke and burning, because carbonising produces fumes.

Step 3: Crush the charcoal

Break the charcoal into a fine powder. A finer, more even powder gives denser briquettes that hold together better. Remove stones and large pieces by sieving.

Step 4: Mix with a binder and water

Powdered charcoal will not hold shape by itself. It needs a binder, usually cooked starch or a similar sticky material, plus water to make a workable mix. Our guide to choosing a binder compares the common choices. Start with small test batches and note the ratios, because the right amount of binder and water depends on your charcoal.

Step 5: Press the briquettes

A press compacts the mix into uniform shapes. A consistent press makes briquettes that burn evenly, stack well and look professional, which matters if you plan to sell them. See the Charcoal Briquette Press Machine and our overview of how it works.

Step 6: Dry thoroughly

Dry the briquettes in the sun or a ventilated shed on racks or mats, turning them from time to time. Drying can take several days depending on weather. Briquettes that are still damp will smoke, burn poorly and may crumble or grow mould in storage.

Test before you sell

Before selling, check that briquettes:

• Hold together when handled and dropped from waist height
• Light easily and burn steadily without a lot of smoke
• Stay hard when stored in a dry place for a few days

Next, read how to price, package and sell briquettes.

• biomass
• charcoal briquettes
• clean cooking