Nutrition Diet: How long does root beer have caffeine in it?

October 9, 2025 •

4 min read

While most popular root beer brands are completely caffeine-free, a few specific brands do contain the stimulant, leading many to ask, "how long does root beer have caffeine in it?". The answer depends entirely on the brand, and for those containing caffeine, it's typically processed within 4–6 hours, although it can linger much longer depending on the individual.

Quick Summary

Most root beer is caffeine-free, but a few notable brands, like regular Barq's, include caffeine. For caffeinated versions, the stimulant's effects and half-life are similar to other beverages. A person's metabolism and sensitivity determine how long it affects their system.

Key Points

Label Check: Always check the ingredient list for the specific root beer product, as some brands like regular Barq's contain caffeine, while most others do not.
Barq's Exception: The most common caffeinated root beer is regular Barq's, containing about 22 mg of caffeine per 12-ounce can.
Caffeine Half-Life: Caffeine from root beer, if present, has a half-life of roughly 4 to 6 hours, though individual metabolism can affect this.
Watch for Varietals: Be aware that some craft or specialty root beers may have caffeinated versions, such as Sprecher's "Rev'd Up" variety.
Nutritional Context: Beyond caffeine, root beer is often high in sugar and calories, which should be considered within a broader nutrition plan.

Most Root Beer Is Caffeine-Free

Unlike many other popular soft drinks, caffeine is not a native ingredient in root beer. Historically, root beer was a herbal concoction, and modern versions are created from carbonated water, sugar, and flavorings—not a caffeine source. For those monitoring or avoiding caffeine, this is generally good news. Most major root beer brands do not add caffeine, making them safe choices for evenings or for people with caffeine sensitivities. However, the one significant exception is regular Barq's Root Beer. Some craft breweries, like Sprecher, also offer caffeinated options, so it is vital to always check the label.

Which Root Beer Brands Have Caffeine?

To help consumers make informed choices, here is a breakdown of the caffeine content in some common root beer brands. The best practice remains to always verify the nutritional information on the specific product you are purchasing, as formulations can sometimes change or special varieties may be introduced.

Caffeinated Root Beer:

Regular Barq's Root Beer: This is the most well-known caffeinated root beer brand. A 12-ounce can contains approximately 22 milligrams of caffeine.
Sprecher Rev'd Up Root Beer: Sprecher Brewing Company offers a caffeinated version of their classic root beer for those who want an extra kick.

Caffeine-Free Root Beer:

A&W Root Beer: A widely available and completely caffeine-free option.
Mug Root Beer: Another popular brand that does not contain any caffeine.
Dad's Root Beer: Known for its classic flavor and caffeine-free recipe.
IBC Root Beer: A gourmet soda brand that is caffeine-free.
Barq's Diet Root Beer: While the regular version contains caffeine, the diet version is caffeine-free.
Virgil's Zero Sugar Root Beer: A healthier, no-caffeine option.

Caffeine Comparison: Root Beer vs. Other Beverages

It is helpful to put the caffeine content of caffeinated root beer into perspective by comparing it to other common drinks. The amount in Barq's is relatively low compared to a typical cup of coffee, but it is still more than zero, which is important for those sensitive to caffeine.


Beverage	Serving Size	Caffeine Content (mg)
Barq's Root Beer	12 fl oz can	22 mg
Drip Coffee	8 fl oz cup	92 mg (average)
Energy Drink (Red Bull)	12 fl oz can	107 mg
Coca-Cola Classic	12 fl oz can	34 mg
Green Tea	8 fl oz cup	28 mg (average)
A&W Root Beer	12 fl oz can	0 mg

How Long Does Caffeine Stay in Your System?

For the small number of root beers that do contain caffeine, the way your body processes it is the same as with any other caffeinated product. The mean half-life of caffeine, or the time it takes for your body to eliminate half of the substance, is around 5 hours in a healthy individual. However, this can vary significantly based on several factors, including:

Individual Metabolism: Some people process caffeine faster or slower due to genetic differences.
Liver Function: The liver is the primary organ that metabolizes caffeine.
Medications: Certain drugs, particularly oral contraceptives, can slow down the rate at which caffeine is cleared from the body.
Other Factors: Age, smoking, and pregnancy can also affect caffeine metabolism.

This means that even a modest 22 mg of caffeine from a can of Barq's can remain in your system for many hours. For example, six hours after consumption, about half the caffeine will still be present, which could potentially disrupt sleep patterns if consumed too late in the day.

Nutritional Considerations Beyond Caffeine

While this article focuses on caffeine, it is crucial to remember the broader nutritional picture of soda consumption. Most root beers, whether caffeinated or not, contain significant amounts of sugar and calories. For example, a 12-ounce can of A&W Root Beer has 170 calories and 46g of sugar. Frequent consumption of sugary sodas is linked to health issues such as weight gain, type 2 diabetes, and dental problems.

For those seeking healthier options, switching to diet or zero-sugar root beer or choosing water or herbal tea instead can be beneficial. Additionally, people with a known sensitivity to caffeine or those managing specific health conditions like high blood pressure or anxiety should exercise caution and always check labels.

Conclusion

In summary, most root beer is naturally caffeine-free, and this is why many assume all brands are. The notable and most common exception is regular Barq's Root Beer, which contains a relatively small amount of caffeine compared to coffee or energy drinks. For those who consume a caffeinated brand, the caffeine will follow the standard metabolic process with a half-life of roughly 4 to 6 hours, though this varies greatly among individuals. When making beverage choices, especially on a nutrition-conscious diet, it is always wise to read the label and consider the full nutritional profile, not just the caffeine content, especially for those sensitive to the substance. For the best health outcomes, moderation is key, and opting for caffeine-free or zero-sugar versions can be a healthier choice. For further information on caffeine content in various products, the Center for Science in the Public Interest is a reliable resource.

Frequently Asked Questions

No, while most major brands like A&W and Mug are caffeine-free, regular Barq's Root Beer is a notable exception that contains caffeine. Some craft varieties may also be caffeinated, so it is best to check the label.

No, despite the regular version containing caffeine, Barq's Diet Root Beer is caffeine-free.

A standard 12-ounce can of regular Barq's Root Beer contains approximately 22 milligrams of caffeine.

The amount of caffeine in Barq's root beer (22 mg per 12 oz) is significantly lower than a typical cup of brewed coffee, which contains around 92 mg per 8 ounces.

Yes, as long as you choose a caffeine-free brand. Look for brands like A&W, Mug, or the diet version of Barq's. Always read the label to be sure.

For most people, the small amount of caffeine in Barq's poses little risk. However, individuals sensitive to caffeine might experience side effects like jitters or disrupted sleep. The higher concern for root beer is often its high sugar content.

Some brands add caffeine simply to provide an extra stimulating effect, similar to other caffeinated sodas. The caffeine is not a traditional ingredient but is added to compete in the beverage market.

The easiest way is to check the nutritional information and ingredients list on the product packaging. The absence of caffeine will usually be clearly stated.