Quick take: There is no single caffeine number for "a cup of coffee." Health Canada publishes useful averages, but the actual amount depends on what coffee you use, how much you dose, how you brew it and how large the finished serving is.
Caffeine questions sound simple until you try to answer them honestly. Someone asks how much caffeine is in coffee, and the internet produces one neat number. The problem is that coffee is not one standardized beverage.
An 8-ounce filter coffee, a 12-ounce mug, a double espresso, a concentrated cold brew and a K-Cup can all start with roasted coffee and still deliver very different amounts of caffeine. The useful approach is to start with reference values, then understand which variables can move the cup away from the average.
What does Health Canada use as an average?
Health Canada lists average caffeine amounts for several common beverages. For a 237 mL or 8-ounce serving, it lists 135 mg for brewed coffee, 179 mg for filter-drip coffee, 76 to 106 mg for instant coffee and about 3 mg for roasted-and-ground decaf. Brewed black or green tea is listed at about 30 to 50 mg for the same serving size.
Those numbers are useful because they show the scale of the category. They are not a promise that every 237 mL cup will match the table.
Why can two coffees be so different?
Start with the coffee itself. Robusta generally contains more caffeine than Arabica. Then look at dose: 20 grams of coffee grounds contain more potential caffeine than 12 grams of the same coffee. Brewing method, water ratio, grind and contact time affect how much of that caffeine reaches the beverage.
Finally, serving size matters. A concentrated espresso can have more caffeine per millilitre while a large mug of drip coffee can contain more total caffeine. We explain that distinction in Espresso vs. Drip Coffee.
Does roast level decide caffeine?
Not reliably. Roasting changes bean mass, density and flavour, but the light-roast-equals-more-caffeine shortcut becomes messy once you change how coffee is measured. If you scoop coffee by volume, darker beans are less dense and you may fit a different mass of coffee into the same scoop. If you weigh the coffee, the comparison becomes much cleaner.
For a deeper roast comparison, see Light vs. Medium vs. Dark Roast Coffee.
How much caffeine should an adult have?
Health Canada recommends a maximum daily caffeine intake of 400 mg for adults aged 18 and over. That is a maximum reference, not a target. People differ in how strongly they notice caffeine and in how quickly they metabolize it.
What about Urban Calm coffee?
Urban Calm uses 100% Arabica coffee. Our regular and mushroom coffees are real roasted coffee, so they contain caffeine unless a product is specifically decaffeinated. Unless we have a product-specific laboratory result for a particular SKU and brew condition, we should not publish a made-up exact milligram number.
Explore the caffeine science
- Espresso vs. drip coffee caffeine
- Arabica vs. Robusta caffeine
- Cold brew caffeine
- How decaf coffee is made
- What determines caffeine in your cup
- How much caffeine is in a K-Cup
- Coffee vs. tea caffeine
- How long caffeine stays in your system
The useful takeaway
If you want one rule, use this one: caffeine belongs to the full recipe, not just the roast name on the bag. Coffee species, dose, brewing method and serving size together tell a much better story than a single generic number.
Sources
Health Canada: Caffeine in Foods
Review: factors that influence caffeine content in coffee brews
Shop Urban Calm Specialty Coffee, roasted in Calgary from Colombian Arabica.
