Aspen – A Gasoline that Does not Smell

Ever heard of gasoline that does not smell? There is indeed such a thing: Aspen alkylate gasoline. Having been available in Europe for decades, Aspen launched their alkylate fuels in US just end of 2020.

In this article, we’ll take a quick look at Aspen gasoline. In summary, Aspen alkylate gasoline is exceptionally refined gasoline with a homogeneous composition practically free of harmful aromatic components. It burns clean, does not foul the engine, has low odor and much lower exhaust emissions than regular meter gas; it also stores well both in tank and on the shelf. Switching to Aspen is usually worth it in low volume use, but the cost may become a concern in very intensive use.

Next, we will go through all of this in more detail. If you’re wondering whether you should switch from meter gas or regular pre-mixed to Aspen (or other alkylate) in your chainsaw and other 2-cycle tools, read on!

What is Aspen fuel?

Aspen fuel is a particularly pure blend of gas called alkylate gasoline. Compared to regular gas from the pump, alkylate gasoline has a much more uniform composition.

In this sense, alkylate fuel is analogous with synthetic motor oil – a more refined and homogeneous product than the base versions.

Aspen fuel and other alkylate gasolines have the particular advantage of containing little to no aromatic components like benzene and polycyclic aromatic hydrocarbons (PAH). These are the smelliest, most easily evaporated and most harmful components in gasoline.

Advantages of alkylate gasoline

  1. Lower fumes and cleaner exhaust
  2. Cleaner burning
  3. Excellent storing: no need to drain from equipment
  4. No stabilizers needed
  5. Preserves rubber, does not attract water (rust)

What is Aspen fuel best for?

1 Outdoor power equipment

Aspen and other alkylate gasolines are particular advantageous in use cases where the engine runs very hot and there is a high interest in lowering the emissions levels.

Air-cooled outdoor power equipment like chainsaws, lawnmowers and weed eaters are a case in point. These small engines run much hotter than water-cooled engines, and also let out their exhaust right next to the user, who may be inhaling exhaust-contaminated air for a large part of the working day.

2 Indoor motorsports

Another use case for alkylate gasoline is indoor motor sports – motocross, cars, go-karts and so on. In these settings the drivers and a possible audience are exposed to exhaust fumes for a prolonged time.

While it will not make the exhaust exactly healthy, alkylate gasoline promotes clean burning and will dramatically reduce the most harmful components in the tailpipe fumes. Some arenas in fact mandate the use of alkylate gas in events.

How does Aspen compare to regular pre-mixed gas?

Aspen and other alkylate gasolines are not only unleaded and ethanol-free, but also much purer than ethanol-free gas or non-alkylate pre-mixed gas.

Regular pre-mixed is usually made from gasoline that is ethanol-free, but is otherwise as meter gas: it has just the same mixed composition and aromatics content, smell and toxicity. It is a bit more stable in the tank though, particularly with the common stabilizer additives.

Alkylate gasoline is very different: it is much more homogeneous in composition and lacks the most harmful and volatile aromatics in particular. The alkylate composition makes these gasolines almost odorless and very stable, so that no stabilizing additives are even needed.

Aspen gas versions

Aspen 2

Aspen 2 is the pre-mixed version of the product: it is a pre-mixed fuel-oil with a mix ratio of 50:1 intended for conventional 2-cycle engines.

Aspen 2 is directly compatible with most small 2-cycle engines which take oil in their gas, such as chainsaws. It is not intended for 4-cycle engines or 2-cycle engines with an auto-lubrication system.

Aspen claims the included 2-cycle oil to be fully synthetic (and biodegradeable), so this component should work well and burn clean too.

Aspen 4

Aspen 4 is Aspen’s gas for 4-cycle engines: it is basically the same alkylate gasoline as Aspen 2, but without the oil.

Aspen 4 is the right choice for all 4-cycle engines and 2-cycle engines with autolubrication. You can also use Aspen 4 as the gas component when mixing your 2-cycle fuel yourself. This would be the case if you want to pick a non-standard gas-oil mix ratio or use some specific 2-cycle oil.

Is Aspen expensive?

Aspen gasoline is slightly more expensive than common pre-mixed gas (TruFuel etc.) and many times more expensive than meter gas.

The table below shows you how much more you will have to pay. Compared to regular pre-mixed, Aspen 2 is around 20% more expensive: ~$30/gal vs. ~$25/gal for TruFuel 50:1 or similar in one gallon quantities. This is not a major difference – only a few dollars in an hour of very intensive chainsawing (w. Husqvarna 572 XP).


Aspen 2$30/gal$19
Meter gas +
Red Armor
* 1 gal quantity
** Husqv. 572 XP

On the other hand, self-mixed meter gas does make for a much, much cheaper fuel, with a total cost per gallon of around $5. In small quantities, Aspen 2 is a whopping 6x more expensive.

Alternatives to Aspen

Besides Aspen, there are not too many other alkylate fuels on the consumer market.

Although the situation is not entirely clear, other pre-mixed gasolines are probably not alkylate. Most pre-mixed brands do not advertise “alkylate” in the product data; moreover, many explicitly mention stabilizers, which are a tell-tale of regular gas. Stihl MotoMix was mentioned to be alkylate somewhere, but the Stihl USA product page makes no such mention.

Neste and a few other small names sell alkylate gasoline globally, but do not seem to have retailers in the US.

Conclusion: Is Aspen worth it?

In my opinion, Aspen gas is probably well worth your money with engines in occasional, seasonal and less intensive use.

In such use, the practical and health benefits easily outweigh the small added cost. Odorless garage and clothes, clean exhaust, less engine maintenance, and leaving the gas in the tool are great practical benefits – all for a few dollars.

In intensive, high-volume professional use, you may have to consider the cost of Aspen more carefully. If you’re running through many gallons a day, you’ll pay ~$100 for the privilege of using alkylate. But you’re also smelling the exhaust for hours and would probably enjoy having it cleaner.

PS. You may also want to read my earlier articles on pre-mixed fuels and the best gas–oil mix ratios; if you’re mixing yourself, my mix calculator is a helpful tool.