Gasoline has a limited shelf life and will eventually go bad if left unused for too long. There are many factors that determine how long gasoline will stay fresh and effective in a 55 gallon drum, including:
The Type of Gasoline
Not all gasoline is created equal when it comes to longevity. The type of gasoline you store makes a big difference:
- Regular 87 octane gasoline – Goes stale fastest, lasting 3-6 months in storage
- Midgrade 89 octane gasoline – Lasts slightly longer at 4-8 months
- Premium 93 octane gasoline – The best choice, lasting 6-12 months in storage
Higher octane gasoline contains more stable compounds that resist breakdown over time. Stick with premium fuels for longest shelf life.
Gasoline Additives
You can extend the life of gasoline by using fuel stabilizer additives that are formulated to prevent oxidation, corrosion, and varnish buildup in stored fuel. Popular options include:
- STA-BIL 360 Marine – Designed for boats, prevents ethanol damage
- STA-BIL 360 Performance – Delays oxidation and stabilizes fuel
- STA-BIL 360 Storage – Locks in fuel quality during storage
- PRI-G Fuel Stabilizer – Anti-oxidant protection for long storage
Be sure to add the proper dose of stabilizer as recommended on the product. This can keep gasoline fresh for up to 2 years in storage.
Container Material
The container used to store the gasoline also impacts shelf life. Some materials do a better job of blocking outside air and elements that accelerate fuel breakdown:
- Stainless Steel – Best protection against corrosion and contamination
- Aluminum – Resists corrosion but more porous than steel
- Fiberglass – Prone to static charge buildup and discharge
- Plastic – Allows more air permeability over time
For longest life, store gasoline in an airtight, corrosion-resistant stainless steel drum with secure seals.
Storage Temperature
Fuel will last longer when stored in a cool, stable environment. Exposure to heat and temperature fluctuations hastens the evaporation of lighter compounds in gasoline. Ideal storage conditions are:
- Temperatures below 70°F
- Away from direct sunlight
- Little temperature variation
- Underground storage best
Avoid storing gasoline drums in hot garages, sheds, or anywhere with big seasonal temperature swings. The cooler the better.
Fill Level
A drum filled to capacity with gasoline will resist evaporation and oxidation longer than partially filled drums. Minimize air space:
- Full drums last 9-12 months
- 80% full lasts 6-9 months
- 50% full lasts 3-6 months
- Less than half full lasts 1-3 months
Top off drums to keep the airspace to a minimum for maximum shelf life.
Condition of Drum
The drum condition also impacts gasoline life expectancy. Look for:
- No dents, punctures or rust
- Intact seals & gaskets
- Properly secured bungs
- Good paint condition
A compromised drum will allow more air and water ingress, accelerating fuel degradation. Inspect drums carefully before filling.
Use of Fuel
Gasoline stored in drums should be used on a first-in first-out basis, not left for exceedingly long periods. The longer stored, the higher likelihood of degradation. Ideal use frequency:
- Under 6 months – Use with confidence
- 6-12 months – Test before use
- 1-2 years – Mix with fresh gas before use
- Over 2 years – Consider disposal
Avoid tapping the oldest drums unless freshly replenished. Oldest fuel may need filtering or blending if stored too long.
Testing Stored Gasoline
The best way to identify degraded gasoline is to have it lab tested. But also look for:
- Color – Should be clear and bright, not dark or hazy
- Clarity – Should not contain sediments or water
- Odor – Should retain strong odor, not weak
- Performance – Should start/run engine without issues
Off-color, smelly, dirty, or poorly performing fuels should be filtered or disposed of. Always test older gas before use.
Signs of Bad Gasoline
Watch for these indicators that stored gasoline has gone bad:
- Gummy residues in engine/fuel system
- Corrosion in tanks/lines
- Poor engine starting
- Rough idle or stallling
- Power loss
- Knocking or pinging
Gasoline with excess varnish, gum, or oxidation byproducts will cause all these issues. Immediately drain and dispose of bad gas showing these problems.
How to Dispose of Bad Gasoline
Gasoline that has degraded significantly should not be used and must be disposed of properly. Options include:
- Contact hazardous waste disposal
- Bring to household hazardous waste facility
- Ask auto shop to drain and dispose of it
- Allow it to evaporate in safe area
Never dump bad gasoline down drains, sewers, or directly onto ground. Check local environmental regulations for proper disposal methods.
Conclusion
With optimal storage conditions using high-quality drums and fuel, gasoline can potentially last 9-12 months in a properly sealed 55 gallon drum before going bad. Lower octane fuels have shorter life expectancy around 3-6 months. Using fuel stabilizers, storing in cool environments, and minimizing airspace extend shelf life. Test all gasoline periodically and watch for signs of degradation before use in engines.
