What Bioethanol Fuel Should I Use — and Does It Matter?

It matters more than most people expect. The fuel you put into a bioethanol fireplace directly affects the quality of the flame, the smell in the room, how cleanly the burner runs, and how often you need to clean it. Most buyers don’t think about fuel until they’ve already purchased a fireplace — and then they reach for whatever’s cheapest or most convenient. That’s understandable, but it’s also where problems start.

The right fuel is invisible. The wrong fuel announces itself — with soot, smell, an unsteady flame, or a sticky residue that builds up inside the burner over time.

What Is Bioethanol Fuel, Exactly?

Bioethanol is a plant-derived alcohol, produced by fermenting the sugars in crops such as wheat, maize, or sugarcane. The resulting ethanol is distilled to a high purity and then denatured — meaning small quantities of additives (typically methanol or a bittering agent) are introduced to make it unfit for human consumption. This is a legal requirement in the UK, not a quality issue.

What you’re buying in a bottle labelled “bioethanol fuel” is essentially a high-purity alcohol formulated to burn cleanly in a ventless fireplace. When it combusts, it produces heat, a small amount of carbon dioxide, and water vapour. No smoke, no soot, no ash — provided the fuel is the right grade.

Purity: The Number That Matters Most

The single most important thing to check on any bioethanol fuel is its alcohol purity, expressed as a percentage. For indoor bioethanol fireplaces, you want a purity of between 95% and 97%.

This range exists for a reason — it’s the band where combustion is cleanest and most complete.

Below 95% and combustion becomes incomplete. Heavier alcohols pass through unburned, depositing soot on the burner and glass and releasing a sharp, chemical smell while the fire is lit. The residue lingers even after you switch to better fuel, so the burner needs a thorough clean to recover fully.

Above 97% and the fuel burns too aggressively. The flame can become unstable, and the rapid combustion can produce an unpleasant oxidation smell. There’s a common assumption that higher purity must mean better quality — it doesn’t. There’s a hard physical reason the number doesn’t reach 100%: ethanol and water form what chemists call an azeotrope at roughly 95.6%, meaning standard distillation simply can’t separate them further. Pushing beyond 97% requires additional processing and removes the small water fraction that actually helps keep the flame steady and controlled.

The sweet spot — the purity most reputable fuel manufacturers aim for — is around 96% to 96.6%. At this level, the fuel converts cleanly to heat, water vapour, and CO₂, with no residual alcohols left over to cause odour or sooting.

What to Look for When Buying

A few practical checks help you distinguish good fuel from questionable fuel:

Purity on the label. Look for a stated alcohol percentage between 95% and 97%. If the purity isn’t stated at all, treat that as a warning sign — reputable manufacturers are transparent about it.

Formulated for fireplaces. The label should clearly state that the fuel is intended for use in bioethanol fireplaces. This matters because not all bioethanol on the market is the same product. Industrial ethanol and automotive-grade ethanol are denatured with compounds designed for engines and exhaust systems, not for burning in an occupied room. They are not interchangeable.

Appearance. Good bioethanol fuel is clear, colourless, and virtually odourless when cold. If it’s cloudy, tinted, or has a strong chemical smell before you even open the cap, the purity is likely too low or the denaturants are not suited to indoor use.

BS EN 16647 compliance. This is the recognised European and UK standard for decorative bioethanol fireplaces. While it applies primarily to the fireplace itself rather than the fuel, manufacturers who test and certify their products to EN 16647 typically specify which fuel grade to use — and using anything outside that specification can affect both performance and warranty cover.

What to Avoid

Gel fuels. These are thickened alcohol products that burn differently from liquid bioethanol. They produce lower heat, leave a sticky residue in the burner, and are not compatible with most bioethanol fireplaces — particularly automatic models. Using gel fuel in a liquid burner can void the warranty and damage the burner mechanism.

Industrial or automotive ethanol. These contain denaturants formulated for industrial processes or vehicle engines, not for indoor combustion in an unventilated appliance. They can release compounds you don’t want in your living room air.

Unbranded or heavily discounted fuel with no stated purity. If the price seems too good to be true, the purity is almost certainly below the recommended range. The saving on fuel is quickly offset by more frequent cleaning, reduced flame quality, and the potential for burner damage over time.

How Fuel Quality Affects Manual vs Automatic Burners

The type of burner in your fireplace determines how sensitive it is to fuel quality — and automatic burners are considerably less forgiving than manual ones.

Manual Burners

A manual bioethanol burner is a simple stainless steel tray. You pour the fuel in, light it, and adjust the flame with a sliding cover. It’s a forgiving design — if the fuel quality is slightly off, you’ll notice a less clean flame and perhaps a faint smell, but the burner itself will continue to function. The residue left by lower-grade fuel can be cleaned relatively easily, and there are no electronic components to be affected.

That said, “forgiving” doesn’t mean “immune.” Using poor-quality fuel consistently will still build up deposits that affect flame appearance and can shorten the life of the burner over time.

Automatic (Smart) Burners

Smart bioethanol burners — like those in the Neverdark and SF Eco-Luxe ranges — are a different matter. These use vapour combustion technology, electronic ignition, fuel pumps, and in some cases automatic filling systems. The fuel passes through precision components — pumps, valves, and fuel lines — before reaching the combustion chamber.

Low-quality fuel with impurities or the wrong purity level can leave residue in these components, potentially affecting the pump mechanism, clogging fuel lines, or interfering with the ignitor. Because the flame is electronically controlled rather than manually adjusted, any inconsistency in fuel quality translates directly into inconsistent performance. For smart burners, using the correct fuel isn’t just a recommendation — it’s essential for maintaining the system and keeping the warranty valid.

Storing Bioethanol Safely

Bioethanol is flammable, and storing it properly is non-negotiable. Keep it in its original sealed container, in a cool, dry area away from direct sunlight and any heat source — including radiators, boilers, and south-facing windowsills. The container should be upright at all times, and the cap should be firmly closed after every use.

Keep it out of reach of children and pets. While the denaturants make it undrinkable, it’s still a flammable liquid and should be treated as one.

Don’t stockpile more than you’ll use in a reasonable period. Bioethanol doesn’t go off in the way food does, but keeping large quantities of flammable liquid in a domestic setting is unnecessary and best avoided. A few weeks’ supply at a time is a sensible approach.

The Short Version

Use bioethanol fuel with a purity of between 95% and 97%, specifically formulated for indoor fireplaces. Check the label for a stated purity percentage and avoid anything that doesn’t declare one. Never use gel fuel, industrial ethanol, or automotive-grade alcohol. Store it safely, refuel only when the burner is cool, and stick with a consistent brand once you find one that works well.

The fuel is a small, recurring cost — explore our bioethanol fireplace collection to see which models suit your space, and if you’re unsure which fuel works best with a particular burner, get in touch. We’re happy to point you in the right direction.