How to Light a Wood Burner: Briquettes Break the Rules

Advice on how to light a wood burner is written almost entirely around split logs. Two big pieces at the bottom, kindling above, firelighter on top, door ajar. It is good advice and it works, and if you follow it with a load of compressed briquettes you will spend twenty minutes watching a firelighter go out against what is effectively a block of wooden brick.

Briquettes and heat logs are not logs with the corners knocked off. They are sawdust and shavings compressed under enormous pressure until the lignin in the wood binds them together, which makes them dense, smooth and low on surface area, and a fire needs surface area far more than it needs fuel. This page is about the method that actually works with them, and about the single limit your stove maker sets that matters more with briquettes than with anything else you can put in the firebox.

Why a briquette will not catch like a log

A split log is covered in exactly the stuff a fire needs. Torn fibres along the split face, sharp arrises where the axe went through, loose bark, a rough surface everywhere. All of it catches at low temperature and all of it feeds the flame while the mass of the log is still cold.

A briquette has none of that. It is smooth on every face, uniform in density, usually higher in density than any natural wood, and it has been dried to a low moisture content in the manufacturing process. That last part is why people expect it to light easily and are surprised when it does not. Dryness is necessary and it is not sufficient. Nothing burns until its surface is hot enough to give off gas, and a smooth dense face takes a long time to get there.

The practical consequence, and the one thing to take from this page if you take nothing else: you need more kindling for a briquette fire than for a log fire, not less, and you need it in contact with the briquette rather than under it.

The method that works

This is the sequence we use, and it is bottom-up rather than top-down for a reason explained in the next section.

1. Check the ash bed and the air. Leave a shallow bed of ash on the base if you are burning wood; it insulates the base and helps the next fire. Open the primary air fully and the airwash roughly half.

2. Build a kindling nest, not a kindling layer. A generous double handful, crossed rather than stacked flat so air can move through it. If you are splitting your own, how to make kindling covers getting it thin enough. Thin matters more than dry here, and both matter.

3. Two firelighters, not one, and put them inside the nest. A single firelighter under a briquette load is the most common failure. Natural wood-wool lighters work well because they burn longer than the white blocks.

4. Light it, and leave the door on the latch. Not open, not shut. A gap of a few millimetres lets air in and keeps condensation off the glass while everything warms up. Stovax’s own instructions put it exactly this way: “Leave the door slightly open as the fire establishes and the glass warms, avoiding the possible build up of condensation.”

5. Wait for a real flame front before the briquettes go anywhere near it. This is the step everyone rushes. You want the kindling properly alight and the firebox visibly warm, which usually takes five to ten minutes, not two.

6. Add one briquette, on its edge, leaning against the kindling. Not flat on top. Edge-on gives you two faces exposed to flame instead of one, and leaning it means air can pass behind it. If you have split briquettes, or a smaller stove, one is genuinely enough at this stage.

7. Only when that one is burning across a face do you add the second. With briquettes you are building heat, not volume. A second block added too early absorbs heat from the first and both sulk.

8. Close the door, then start closing down the primary air. Not before. Closing the air down while the flue is still cold is the fastest way to a smouldering fire and a dirty glass, and it is the behaviour the Defra Burn Better campaign, which HETAS supports, exists to discourage.

A useful hybrid if you like the top-down method: build the top-down fire with split logs as normal, and switch to briquettes only for the second load, once the stove is hot. Briquettes are excellent at holding a fire and mediocre at starting one. That is also the logic behind keeping a wood burner in overnight.

Top-down versus bottom-up, and what your stove maker actually says

The top-down method is genuinely better for smoke, for split logs, in a stove that is up to temperature and on a flue with decent draught. Nobody sensible disputes that.

What is worth knowing is that the manufacturers do not universally recommend it. Stovax’s published instructions for lighting a multi-fuel stove are unambiguously bottom-up: “Fully open the Primary air control and half open the Airwash control. Place a firelighter or paper together with dry kindling wood on the grate and light the firelighter or paper … Add slightly larger pieces of wood to build the fire. Add your fuel.”

With briquettes, the bottom-up version wins for a straightforward physical reason. Top-down relies on burning embers dropping onto the fuel below and catching it. Embers fall onto a briquette and sit on a smooth face doing very little. Flame passing across an edge is what gets a briquette going, and flame goes up.

The load limit nobody reads

This is the rule that briquettes break most often, and it is in the manual of practically every stove sold in Britain. Stovax states it plainly on the same page: “Do not smother the fire” and “Do not load fuel above any log guard that is fitted, or any secondary air outlets in the back of the firebox.”

Read that second sentence again, because it is a physical line in your firebox, not a number of blocks. The secondary air outlets are the row of small holes at the back or top of the firebox that feed the airwash and burn off the gases coming out of your fuel. Block them and you lose the clean part of the combustion, the glass blacks up, and the stove starts making the smoke your neighbours notice.

Briquettes are the fuel most likely to breach that line, for two reasons. They stack neatly, so it is easy to build a wall rather than a fire. And several types visibly swell as they burn, particularly the sawdust-and-lignin blocks, so a load that sat comfortably below the log guard at the point of lighting can be pressing against it twenty minutes later.

So: load to about two thirds of the log guard height, not to the top of it. Leave the difference for expansion. If you routinely need more heat than that gives you, the stove is too small for the room, and no loading pattern fixes that.

Our reviews of the common UK blocks cover how each behaves in practice, including which swell most: Lekto sawdust briquettes, Ecoblaze RUF fire blocks and Lekto night briquettes, with the full field in the best wood briquettes in the UK.

Four mistakes that stop a briquette fire

Using briquettes as kindling. They are the opposite of kindling. Nothing about a dense smooth block is designed to catch.

Loading flat and stacked. Two briquettes face to face have almost no air between them. Stand them on edge, angled, with gaps.

Closing the air down too early. A briquette that has not properly caught will smoulder for a long time and produce a lot of tar. If the glass is going black in the first half hour, you closed down too soon.

Starting from cold with briquettes only. On the first fire of the season, with a cold flue and no draught yet established, use split kiln-dried logs to get the chimney warm and switch to briquettes afterwards. Kiln dried logs versus briquettes sets out where each is the better buy.

Buying the right thing in the first place

Manufactured solid fuels sold for domestic burning in England are covered by the Air Quality (Domestic Solid Fuels Standards) (England) Regulations 2020, which is why briquettes on sale here carry a certification mark and a certificate holder’s name and number. That mark tells you the fuel is compliant. It does not tell you how it lights, how long it holds or how much it swells, and there is no standard measure of any of those.

What is worth checking before you buy a pallet:

• Shape. Round Nestro-style cylinders with a hole through the middle light considerably more easily than solid rectangular RUF blocks, because the hole is surface area and a chimney in miniature.
• Whether they are splittable. Some blocks will break in half with a firm knock, which effectively gives you a smaller starter piece and doubles your options.
• Density and swell together. The densest blocks give the longest burn and the most expansion. That is a good trade for an overnight load and a poor one for a quick evening fire.
• A moisture meter is still worth owning, even with manufactured fuel, because it is the only way to check the split logs you burn alongside them. See how to use a moisture meter on firewood.

If you are still choosing between fuels rather than lighting them, the best wood to burn and the UK firewood buying guide are the places to start, and Ready to Burn firewood rules covers what the certification actually guarantees.

Frequently asked questions

How do you light a wood burner with briquettes? Build a generous crossed nest of kindling with two firelighters inside it, light it with the primary air fully open and the door on the latch, and wait five to ten minutes for a real flame front and a warm firebox before adding anything else. Then add a single briquette on its edge leaning against the burning kindling, and only add a second once the first is burning across a face.

Why will my briquettes not light? Almost always because there was not enough kindling, or because the briquettes went in too early. A briquette is smooth, dense and low on surface area, so it needs sustained flame against an edge rather than embers underneath it. Dryness is not the problem: manufactured briquettes are already dry.

Should I light a wood burner from the top or the bottom? Top-down is cleaner with split logs in a stove that draws well. For briquettes, bottom-up works better, because falling embers do very little to a smooth face while rising flame catches an edge. Stovax’s own multi-fuel lighting instructions are bottom-up, so this is not a fringe view.

How many briquettes should I put in a wood burner? Enough to reach about two thirds of the log guard height, and no more. Stove makers set the limit as a physical line rather than a count: do not load fuel above the log guard or above the secondary air outlets at the back of the firebox. Briquettes swell as they burn, so a load that fits at lighting can be blocking those outlets half an hour later.

Do wood briquettes expand when burning? Many do, particularly compressed sawdust blocks bound by their own lignin. This is normal and it is why you leave headroom in the firebox rather than filling it. The densest, longest-burning blocks tend to expand most.

Can I use briquettes to start the fire instead of kindling? No. They are the least suitable thing in the shed for starting a fire. Use thin split kindling and firelighters, and bring the briquettes in once there is a proper flame.

Why is my glass going black when I burn briquettes? You are closing the air down before the fire is properly established, or the load is blocking the secondary air outlets that feed the airwash, or both. Get a hot fire first, keep the load below the log guard, and only then reduce the primary air.

Do briquettes need to be Ready to Burn certified? Manufactured solid fuels sold for domestic use in England fall under the Air Quality (Domestic Solid Fuels Standards) (England) Regulations 2020, so compliant briquettes carry a certification mark with the certificate holder’s name and number. Look for it, but do not read it as a guide to how well the fuel lights or how long it lasts, because it measures neither.