Caffeine in Popular Sodas: A&W, Barq's, and More

A&W root beer is not listed in the dataset here; a reasonable estimate is 0–22 mg (estimate) of caffeine per can depending on the variety (many root beers are caffeine-free while Barq's contains 22 mg per 355 ml).

• Barq's Root Beer (355 ml) contains 22 mg of caffeine — a low dose compared with colas and energy drinks.
• Coca-Cola (355 ml) has 34 mg46 mg54 mg.
• Energy drinks and cold-brew coffee can be 4–10× higher: Red Bull 250 ml = 80 mg, Monster 473 ml = 160 mg, cold brew 240 ml = 200 mg.
• FDA recommends a max of 400 mg/day for healthy adults; pregnancy guidance ~200 mg/day; American Academy of Pediatrics discourages routine caffeine for adolescents.

Root beer caffeine: Barq's vs A&W

Barq's Root Beer is listed in the dataset at 355 ml = 22 mg (6.2 mg/100 ml). A&W root beer is not in this dataset, so we cannot state an exact number from these data. Many commercial root beers are produced both as caffeine-free and caffeinated varieties; where caffeine isn’t listed you should assume 0 mg unless the label or manufacturer says otherwise. Use USDA FoodData Central or the product label for definitive values.

How caffeinated are common sodas (quick comparison)

This table lists popular sodas and similar soft drinks from the dataset so you can compare at a glance.

Drink (serving)	Caffeine (mg)
Coca-Cola (355 ml)	34 mg
Diet Coke (355 ml)	46 mg
Coke Zero (355 ml)	34 mg
Pepsi (355 ml)	38 mg
Mountain Dew (355 ml)	54 mg
Dr Pepper (355 ml)	42 mg
Barq's Root Beer (355 ml)	22 mg
Sunkist Orange (355 ml)	41 mg
Club-Mate (330 ml)	66 mg
Iced tea, bottled (355 ml)	45 mg
Red Bull (250 ml)	80 mg
Monster (473 ml)	160 mg

How soda caffeine compares with coffee and energy drinks

Sodas are low-to-moderate sources of caffeine compared with coffee and many energy drinks. For context from the same dataset: a standard drip coffee (240 ml) = 96 mg, cold brew (240 ml) = 200 mg, and a Starbucks Grande Pike Place (473 ml) = 310 mg. Energy drinks like Monster (473 ml) at 160 mg or Bang (473 ml) at 300 mg deliver far more caffeine than a can of cola or root beer.

What determines caffeine in a soda

Key variables are formulation and serving size. Cola-style sodas usually contain added caffeine as an ingredient; root beers are often made without added caffeine. Citrus sodas and many orange sodas (e.g., Sunkist) often include added caffeine at levels similar to cola. Manufacturer recipe changes, regional formulations, and serving volume (ml) explain most variation. For verified amounts, consult product labels and USDA FoodData Central entries; regulatory bodies like the FDA monitor labeling standards.

Health, safety, and timing

Regulatory and clinical guidance is a helpful guardrail: the FDA cites about 400 mg/day as a safe upper limit for most healthy adults; many authorities (and some studies cited by EFSA) recommend less during pregnancy—commonly ≈200 mg/day. The American Academy of Pediatrics advises limiting caffeine in adolescents.

Caffeine metabolism is population‑average: half-life ≈ 5.7 hours. In other words, caffeine from a drink declines exponentially; after ~3 h about 69% remains, after 6 h about 48%, after 9 h about 33%, after 12 h about 23%. This matters for night-time intake and sleep.

Drink (typical dose)	Initial mg	After 3 h (~69%)	After 6 h (~48%)	After 9 h (~33%)	After 12 h (~23%)
Barq's Root Beer (355 ml)	22 mg	15 mg	11 mg	7 mg	5 mg
Coca-Cola (355 ml)	34 mg	23 mg	16 mg	11 mg	8 mg
Mountain Dew (355 ml)	54 mg	37 mg	26 mg	18 mg	12 mg
Red Bull (250 ml)	80 mg	55 mg	38 mg	26 mg	18 mg

Practical tips and tracking

To manage intake: read product labels, favor caffeine-free versions if you need zero caffeine, and note serving sizes. If you need to total daily intake (and include coffee, tea, and energy drinks), track every drink — apps like CoffeeLog make logging straightforward and can add values from manufacturer data automatically. If you are pregnant, have cardiovascular issues, anxiety, or are giving advice for children, consult a healthcare professional; information here is educational, not medical advice.

Bottom line

Barq's root beer provides 22 mg per 355 ml; many other root beers (including some A&W varieties) are caffeine-free, which is why an A&W value is estimated here as 0–22 mg (estimate). For absolute certainty check the label or USDA FoodData Central and use a tracker like CoffeeLog to sum caffeine across drinks and time.

Sources and guidance referenced in this article include USDA FoodData Central, the U.S. Food and Drug Administration (FDA), European Food Safety Authority (EFSA) summaries, the Mayo Clinic, and the American Academy of Pediatrics.