How to check pellets at home in 5 minutes: 6 tests without a laboratory

What you will need

One bag of pellets (ideally a trial bag rather than one from the middle of a pallet you have already bought), a glass of water, kitchen or floor scales, a metal plate or dustpan and a light-coloured surface: a sheet of paper or a table. All the tests together take 5 minutes, plus 10 minutes of waiting for the water test.

Test 1. The bottom of the bag: how much dust

Cut the bag open and empty it onto a light surface or into the hopper, then look at what is left at the bottom and what has collected at the base of the pile. The ENplus standard allows up to 1% fines and dust, i.e. no more than 150 g from a 15 kg bag, roughly a handful. A finger-thick layer of sawdust is already 3-5%: the pellets are brittle or the bags have been handled many times. Dust like this clogs the auger and causes flare-ups in the pot, which then grow into cakes.

Result: a handful is good; two or three handfuls are tolerable for a boiler with a large pot; a layer means do not buy the batch for the season.

Test 2. Breaking and dropping

Take a pellet and try to break it with your fingers. A good one breaks with effort, with a clean "glassy" fracture, rather than crumbling into sawdust. Drop a few pellets from table height onto a concrete floor: they should bounce and stay whole or split into 2-3 pieces, not fall apart. This is the household equivalent of the mechanical durability test (the standard requires 97.5-98% or more).

Result: hard to break and intact after dropping is good; crumbles between your fingers means weak pressing or a batch that has got damp, and in the auger it will turn to dust.

Test 3. Water

Put a few pellets in a glass of water. Proper pellets sink straight away (their density is above one), swell within 5-10 minutes and break down into uniform sawdust, while the water stays clear or slightly cloudy. Pellets that float have low density and weak pressing. A film or oily rings on the water mean binding additives, which should not be present in wood pellets. Sawdust that separates into light and dark layers means the raw material contains bark or furniture production waste. A pellet that does not break down after more than 15 minutes means treated wood or glue.

Result: sank and broke down into clean sawdust is good; floating pellets or a film on the water means do not buy.

Test 4. Colour, surface, smell

Spread a handful on light-coloured paper. Softwood pellets are light beige with a slight sheen, smooth, with ends that look cleanly cut; hardwood pellets are a little darker, up to light brown. Warning signs: black or dark brown specks (bark, soil: ash and clinker), a greyish tint and a dull rough surface (overheated or poorly pressed raw material), a mixture of pellets of different lengths from 5 to 50 mm (an unstable press). The smell should be of fresh wood or have a slight "baked" note; a sharp, chemical or husk smell means impurities.

Result: uniformly light, smooth and smelling of wood is good; mottled with black specks or with a foreign smell means do not buy for a household burner.

Test 5. Bag weight

Weigh the bag on household scales. The norm is the stated weight plus or minus 2-3%: for a 15 kg bag that is 14.6-15.4 kg. A systematic shortfall of 0.5-1 kg per bag is 3-7% of the cost of a pallet, i.e. several hundred hryvnias on every tonne. It is best to check in front of the driver: with us, control weighing is part of the delivery terms, and if a bag is underweight we make up the weight or refund the difference.

Result: within tolerance is good; less means demand a recalculation straight away, as it is harder to prove after payment.

Test 6. Burning on a plate

Put a few pellets on a metal plate or dustpan and light them with a gas burner or a lighter (a pellet catches in 20-40 seconds). Good pellets burn with an even yellow-white flame without crackling, there is almost no smoke, and after burning a pinch of light grey loose ash is left that you can blow away. Bad signs: black sooty smoke, crackling and sparks (moisture or resin from bark), and above all a fused black or brown lump instead of ash. That is a miniature cake: in a burner, this fuel will produce one within a few hours.

Result: light loose ash is good; a fused lump means do not buy the batch, especially for a flame burner.

When the results contradict each other

It happens: the pellets are strong and light-coloured, yet the ash fuses, which means the raw material contains sand or husk and the colour did not give it away. Or the pellets crumble a little but burn cleanly: weak pressing with clean raw material, which is acceptable for a retort burner but not for a flame burner. The rule is simple: the decisive tests are water and burning, the rest are clues. And no home test replaces the ash content figure in the batch certificate: if the seller cannot show you a certificate, that in itself is a result.

What to do with the result

If the trial bag has passed all six tests, buy a pallet from the same batch (ask for the batch number or production date, as pellets from another batch may differ). If it has not passed, do not try to "come to terms with the boiler" through settings: that will cost more than the price difference between batches. How to choose the grade and raw material for your boiler is covered in the article "How to choose pellets"; how to avoid a seller whose every bag is different is covered in the article "How not to get caught by scammers".