Diesel Exhaust Fluid (DEF)

Keep your fleet running clean and compliant with our high-quality DEF

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Diesel Exhaust Fluid

Premium-quality DEF with E.H. Wolf

Our DEF has a recommended shelf life of 12 months under proper storage conditions. It promises uncompromised purity and effectiveness and can still deliver exceptional performance even if stored for an extended period, provided it meets rigorous quality standards through analysis. At EH Wolf, we prioritize your satisfaction and offer adaptable storage solutions tailored to your specific needs.

With EH Wolf & Sons' premium DEF, you can experience the confidence of clean emissions and optimal engine performance. Trust in our commitment to purity, service, and customer satisfaction as we pave the way for a brighter, more sustainable future on the road.

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How does DEF work?

The process starts when DEF is delivered by Wolf or dispensed from a Wolf station—keeping a reliable supply of high-quality fluid so your system runs clean.

DEF Storage

A dedicated tank stores DEF—a solution of 32.5% urea and 67.5% deionized water.

DEF Injection

DEF is injected into the exhaust stream upstream of the Selective Catalytic Reduction (SCR) catalyst.

Ammonia Formation

Upon injection, DEF thermally decomposes to form ammonia (NH3) and isocyanic acid (HNCO).

SCR Catalyst Reaction

Ammonia reacts with nitrogen oxides (NOx) over the SCR catalyst, converting them into nitrogen (N2) and water vapor (H2O).

Emission Output

The result is a significant reduction in NOx emissions—releasing cleaner exhaust into the atmosphere.

E.H. Wolf is the Midwest’s DEF Experts

We prioritize purity because less than one-tenth of a teaspoon of the minerals found in tap water, dust, and the air can cause damage within the SCR system. All of our DEF is transported in dedicated, sealed DEF containers for protection from contamination.

To maintain the warranty on their vehicles, manufacturers of heavy-duty vehicles require diesel exhaust fluid of high purity. All of of the DEF brands we offer are reliable and certified fluids that meet the ISO 22241 standard, ensuring its purity and composition. It is supplied in specially designed, sealed containers to safeguard against contamination, and to protect the vehicle's catalyst from damage.

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Our fleet of tankers that are specifically designed to carry DEF and are made of stainless steel.

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Rest assured that our DEF offerings are premium-quality guaranteed. Look for the stamp to confirm that you're receiving a top-notch product.

Learn about premium quality at Wolf

We offer a wide range of packaging options to help you personalize your DEF storage solution. Whatever your need may be, we have the right packaging solution for you.

A carton of Kleen DEF Diesel Exhaust Fluid with a plastic dispenser tube sticking out of the opening.
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A large white plastic E.H. Wolf IBC tote with a black cap and a valve at the bottom, encased in a metal cage, with the true-blue "Wolf" logo on the side.
A blue barrel with the word 'DEF' written on it and a logo at the bottom.

combination deliveries

55-gallon drums

2.5-gallon containers

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A large white plastic E.H. Wolf IBC tote with a black cap and a valve at the bottom, encased in a metal cage, with the true-blue "Wolf" logo on the side.

bulk deliveries

275-gallon totes

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Need a steady supply of DEF? We’ve got you covered.

Whether you're managing a large fleet that requires hundreds of gallons weekly or running a fuel station offering DEF at the pump, we provide reliable bulk Diesel Exhaust Fluid solutions. With custom delivery schedules, competitive pricing, and strategic planning, E.H. Wolf & Sons ensures you never run low—and never have to wonder what's next.

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We offer a variety of choices for your DEF needs. We are committed to promoting products that care about the environment. Our two most popular brands are BlueDEF™ and Musket DEF. Contact us to learn more about our brands.

The BlueDEF logo. It features the words 'Blue DEF' in blue and black text, with a water droplet icon at the end.

Since diesel exhaust fluid was first introduced in 2009, BlueDEF has been the nation’s market leader. BlueDEF® built its strong brand position through strategic partnerships with NHRA, NASCAR and PBR. BlueDEF® diesel exhaust fluid meets ISO 22241 standards and is certified by the American Petroleum Institute.

The Musket logo. It features a circular emblem containing stylized lines and the word 'MUSKET' in bold letters.

Musket started producing diesel exhaust fluid in 2014 to fulfill the increasing market demand and optimize logistics. As a top-quality DEF supplier, they operate 24/7/365 with flexibility, stability, product integrity, and overall competitiveness. Their QA/QC procedures surpass industry standards throughout the supply chain to produce high-quality DEF that meets ISO 22241 standards.

DEF FAQs

  • Diesel Exhaust Fluid (DEF) is a non-hazardous solution, which is 32.5% urea and 67.5% deionized water. DEF is sprayed into the exhaust stream of diesel vehicles to break down dangerous Nitrogen Oxide (NOx) emissions into harmless nitrogen and water. This system is called Selective Catalytic Reduction (SCR) and can be found on 2010 and later model year trucks and many diesel pickups and SUVs. DEF is not a fuel additive and never comes into contact with diesel. It is stored in a separate tank, typically with a blue filler cap.

  • In January 2010, the EPA set new standards requiring vehicles to significantly reduce emissions. Using DEF in diesel-powered vehicles helps reduce the amount of nitrogen oxides (NOx) emitted into the air by 90%. Most new diesel vehicles have DEF tanks that must be regularly refilled.

  • Diesel Exhaust Fluid consumption is measured as a ratio of diesel fuel use, normally termed the "dosing rate" or "treat rate". Medium- and heavy-duty vehicles have a dosing rate of 2-3%. This means that if your truck has a fuel efficiency of six miles per gallon and a dosing rate of 3% it will use approximately 1 gallon of DEF every 200 miles.

  • If your truck runs out of DEF the engine's power is reduced and a solid red warning will be displayed. The vehicle’s speed will be limited to 5 mph until the DEF tank is refilled.

  • You can purchase DEF right from us! We can also provide all the parts and dispensing equipment you may need for DEF delivery systems and maintenance, including: pumps, hoses, filters, nozzles, and tanks. Please contact us if you have any questions or are ready to place an order.

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  • Yes, DEF freezes at 12°F (–11°C). However, vehicle systems are designed with heated tanks and lines to thaw DEF and maintain proper flow.

  • DEF has a shelf life of about 12–24 months depending on storage conditions. Keep it sealed and stored in a cool, dry place to extend its usability.

  • No. Using anything other than certified DEF can damage your SCR system and void warranties. Always use DEF that meets ISO 22241 standards.

  • There is no dyed DEF—genuine DEF is always clear and colorless. Any DEF that is dyed or discolored is likely contaminated and should not be used. Even the well-known brand BlueDEF, is clear.

  • Store DEF between 12°F and 86°F in a sealed container, away from sunlight and contaminants. We offer tanks and accessories to help maintain purity.

Diesel Exhaust Fluid

Industries We Serve


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Important DEF Reminders

Fill DEF in the designated DEF tank

If DEF is filled into the diesel tank, the engine will stop running after a short period of time and can possibly cause severe damage to the engine fuel and SCR system. Check then double check when filling your tanks.

Keep DEF dispensing equipment clean & free of dust or dirt

Contaminated DEF will affect SCR system performance and can lead to engine de-rating and even engine damage.

Use dedicated DEF equipment when handling DEF

DEF is highly sensitive to airborne and residue contamination. We offer solutions and handling techniques to help ensure product purity.

Regularly check your equipment

Maintaining DEF dispensing equipment is essential for uninterrupted performance. We can service tanks, pumps, and other equipment to keep systems in top condition.

Never use containers that are used to store other fluids

Even if a container is thoroughly cleaned after storing or transporting other liquids, the risk of contamination remains high.

Do not fill diesel fuel into the DEF tank

Contaminated DEF hampers SCR performance and can result in permanent engine damage. Keep DEF pure and uncontaminated for optimal operation.

Do not use expired DEF in your equipment

DEF can be stored for up to one year in ideal conditions. Store in a cool, dry location out of direct sunlight between 12–86°F (-11–30°C).

Do not add water or any other liquid to DEF

SCR systems require DEF at 32.5% urea and 67.5% deionized water. Altering this ratio can damage equipment and won’t save money.

Diesel Exhaust Fluid at Wolf

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Initial site survey at no charge

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The latest DEF dispensing equipment

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Expert installation of DEF equipment

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Scheduled DEF deliveries to your site

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Competitive DEF pricing for all industries

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On-site equipment and tank inspections

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Advanced product handling to ensure purity & reduce potential contamination

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Tank monitoring devices

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Emergency DEF deliveries and service