Letter Re: Winter Fuel Blends and Fuel Storage Life

If [liquid fuel] prices continue to plummet then a good thing to do is stock up on winter fuels when prices bottom out. Didn’t you say winter/cold weather fuels have an advantage over warm weather production? – Jason in North Idaho

JWR Replies: Yes, gasoline formulations do vary seasonally here in the United States. Here is a good reference on the subject, although I think that it overstates the risk of vapor lock running winter blend gas in the summer. The most notable difference is that winter blends are oxygenated in some regions of the country (typically with a light admixture of ethanol) and extra butane is added nationwide, to make starting engines easier in cold weather. The ethanol does not significantly affect the storage life of the gasoline. However, because the butane gradually evaporates from stored fuel, it is best to store “winter” blended fuel. (This generally available at gas stations between October 15th and April 15th of each year. The extra butane will typically make the fuel viable for an extra year. Regardless of the blend that you buy, you should store it in sealed, full containers that will not allow moisture to be absorbed from the atmosphere. Also, be sure stabilize it with PRI-G, STA-BIL, or a similar product. Also, be sure to buy a couple spray cans of ether-based engine starting fluid. That way you can probably still start an engine even when using very old gasoline that no longer has any significant quantity of butane. (Inevitably though, even if you compensate for the loss of butane and avoid water contamination, even well-stored stabilized gasoline will build up tars, gums, and esters as the gasoline decomposes. To assure that you have at least one vehicle that is still operable three+ years into a long term scenario, be sure to buy a diesel or perhaps a liquid propane (LP) conversion vehicle. Both of those fuels store much longer than stabilized gasoline!