Having diesel on hand can be useful if you need fuel for a bug-out vehicle or want to power a generator.

However, the shelf life of diesel may be shorter than you think.

When a widespread emergency occurs, fuel is often one of the first things to go.

Don’t expect to drive to your local gas station to fill up during a major storm or when the economy collapses.

Having a sufficient amount of fuel available in storage can help you stay prepared for unexpected situations, such as sudden blackouts.

Diesel fuel can remain viable for between 6 and 12 months at a temperature of 85 degrees Fahrenheit, according to Kendrick Oil Company.

Once the fuel has surpassed its expected lifespan, it will start to react with oxygen in the tank, causing the diesel to take on a gummy consistency.

Although the fuel may still burn at this point, it will not burn well and will likely leave a layer of carbon and soot on the inside of the engine.

Storing diesel in the proper conditions can prolong its shelf life and prevent it from going bad prematurely.

However, there’s no denying that diesel doesn’t last as long as it used to.

According to Bell Performance, in the 1950s the U.S. Army reported that stored diesel fuel lasted an average of three to five years.

Today, the lifespan of diesel fuel is less than one year.

How Long Diesel Fuel Lasts

The diesel fuel that is sold nationwide today is known as ultra-low sulfur diesel. As this type of fuel is low in sulfur, emissions are lower.

However, low-sulfur also means that the fuel doesn’t last as long. When kept at an optimal temperature of between 70- and 85-degrees Fahrenheit, diesel can last about 6 to 12 months before it begins to degrade. If the temperature is kept below 70 degrees Fahrenheit, diesel can last slightly longer.

Most diesel does not last more than 18 months before experiencing degradation.

To slow down the process of degradation, it is important to keep the fuel cool, clean, and dry in storage.

If you want to keep your fuel longer than one year, you will need to follow some important steps. First, make sure that you only purchase fuel from a reliable supplier and that the fuel purchased is dry and clean. You’ll also want to make sure that the fuel is of good quality and is stable through the use of additives, such as biocides.

Ideally, you want the fuel to have been regularly tested and rigorously maintained.

Factors That Effect Diesel Fuel Quality

To better understand how long diesel lasts, you must know what makes it go bad. While there are several culprits, some of the most common include heat, water or condensation, microbial activity (fungal and bacterial growth), and contact with copper or zinc.

Even if you live in a dry climate, there is still a chance that condensation may occur within the fuel tank, causing water to mix with the fuel. Condensation can cause the fuel to gel up, and can also encourage fungus and bacteria growth.

While you can still use diesel fuel that has expired or gone bad, doing so can cause extensive damage to your machinery. Diesel that has taken on a gel consistency can clog up the filters in your engines causing the machinery to fail. To prevent damage to your machine, look for signs that indicate that your fuel has gone bad. Some of these signs include:

Poor fuel efficiency

Dark color

Sludge or gel in fuel

Frequently clogged fuel filters

Sediment in fuel

Difficulty starting machinery

Black smoke

Rotten odor from microbes

Other factors can also affect fuel quality, such as whether or not there is any biodiesel in the fuel, and in what amount. Biodiesel increases the fuel’s ability to hold water and can encourage microbial issues.

Being proactive by regularly removing water buildup from the tank can help reduce the microbial presence and prolong the shelf life of the diesel fuel.

What you should be storing your fuel in

What color to store fuel in

To store fuel, you can’t just use any old container. First, you should be picking the right color. If you take a look at the chart below, you will see that there is an international standard on what fuels and oils belong to what color. For diesel, we need to use a yellow container.

Properly Storing Diesel Fuel

If you plan on storing diesel fuel, do not store more than you could use in 12 months. Over the year, continue to use the diesel so that it does not go to waste, replacing what you have used with new fuel.

By rotating your stockpile, you can avoid waste and prevent your fuel from expiring before you have a chance to use it. I’ll use it in the lawnmower, car, or run the generator to get rid of the old fuel. I try to make sure I fill up my new reserve with ‘fresh’ gas (when the truck has delivered new stock to the station).

Diesel storage drums are available in a variety of sizes, ranging from 5 gallons up to 55 gallons and larger.

While these fuel drums do an adequate job at keeping the diesel sealed while in storage, they do not have drains at the bottom which would allow for the removal of sediment. To prevent the fuel from prematurely expiring, it is essential to maintain the drums.

Keep the drums in a dry, cool place. If water should happen to get on top of the drums, remove it to prevent the drums from corroding, which could negatively impact the fuel. Ideally, you should store the drums in a space that is temperature-consistent as fluctuations in temperature can cause condensation inside the drums.

When you use up all of the fuel in a drum, be sure to clean it before refilling it.

While drums are one of the most common ways to store fuel, they’re not your only option.

If you want to store a large amount of diesel, you may be interested in a diesel storage tank. Unlike most drums, diesel tanks have a drain at the bottom which allows you to drain sediment, water, and sludge that may accumulate at the bottom. There are several things you can do to make the diesel in these tanks last longer.

First, consider installing the tank underground. Although this option can be more costly and involve extra labor, maintaining an underground diesel tank can be beneficial as it helps to keep the fuel cool and at a fairly consistent temperature.

If you are going to leave the tank above ground, try to cover it with a roof. Those who live in cold climates may need to insulate their tanks to prevent ice and gel from forming. You also want to check your fuel regularly to look for signs of degradation.

Making Diesel Fuel Last Longer

Make your diesel fuel last longer by implementing biocide and fuel stability treatments. Biocides are designed to help kill any active fuel bacteria growth that may occur within the fuel storage tanks. Fuel stability treatments help prevent the breakdown of fuel by initiating chemical reactions.

While diesel biocides can prevent the fuel from going bad, you cannot simply pour biocide into a diesel tank. To ensure that the biocide works properly, you will need to recirculate the fuel for about 30 to 60 minutes depending on the volume of diesel being treated.

Recirculating the fuel helps it to blend well and reach all of the bacteria in the tank. You should also allow the fuel to sit before using it as this encourages any dead microbes to settle at the bottom. Also, be sure to replace the filters for several days following treatment to prevent the dead microbes from clogging up the filters.

In addition to biocides, you will also want to use stabilizers to prevent oxidation and acid-based reactions in the fuel. Stabilizers can prolong the lifespan of diesel by several years by preventing the chemical chain of reactions that occur due to oxidation of the fuel.

Also, consider adding water absorbers to your fuel. Water absorbers help to attract water molecules so that the water and molecules can bond, causing the water to burn off as steam. The use of water absorbers is essential if you live in a humid climate or a climate that experiences drastic temperature fluctuations.

Adding Diesel to Your Emergency Storage

In 2007, the Environmental Protection Agency (EPA) called for a change to ultra-low sulfur diesel (ULSD). While the use of ULSD has several advantages, there are also problems such as water contamination and fuel microbes.

There is also the issue of ULSD not lasting as long as prior fuel options.

To work around these problems and keep your diesel lasting as long as possible, it is important to store and maintain the fuel properly. With proper storage and maintenance, you can have a healthy supply of diesel on hand for when you need it for SHTF scenarios.