Well, answering the question of how much caffeine is in your cup of coffee isn’t that easy of a question to answer. There’s so many variables, including roast type, type of bean, how much ground coffee goes into making the pot of coffee, brewing methods, etc.
You can get a wide range of possible levels, according to some sources.
As you can see here in the charts posted by Mayo Clinic, the range can be wide for those of us who need to be careful of our caffeine intake.
The USDA Scientific Report of the 2015 Dietary Guidelines Advisory Committee states that they consider 3 to 5 cups per day to be up to 400 mg of caffeine. This still indicates there are variables in their research. I get a variable of 80mg to 134mg per cup of coffee, using their report.
So, how does one narrow down this down to accurately tell what is safe to drink in a day?
If you mostly drink coffee that comes from the same source, you may be able to find more definite caffeine amounts around the internet. Let’s see how we can do this…
One source is caffeine informer’s chart. They look at labels for caffeine content. If it’s not there they look at the brand’s website. If it’s not there, then they call the company to get the information…and then keep calling until they disclose the caffeine amount.
Since I make cold brew and drink that almost exclusively, I use Aaron Braun’s measurements, as reported in the article at scaa.org. I did check to make sure I was using same ratio of coffee grounds to water as he does too. This gives me a measurement of 159mg per 8 ounce cup of full caffeinated coffee and 17mg per 8 ounce cup of decaf coffee.
NOTE: With cold brew you get to choose the ratio of cold brew concentrate to water in your coffee. I fight high blood pressure so I’m careful to stay down to 1 part coffee concentrate to 3 parts water, which is the 159mg caffeine. My husband does not have a blood pressure problem and drinks his at 1 part water to 1 part coffee concentrate. That is 259mg caffeine per 8 ounce cup.
The other coffee I drink is Starbucks when I go out to work in coffee shops. You can ask for decaf or shoot for the tea lattes if you’re a caffeine watcher. (Just look at menus for smoothie drinks if you go that route and calories matter too.) For measuring their caffeine levels, see their website.
I did find a message board stating that each 10mg of Arabica coffee contains about 100mg of caffeine. When the person using the measurements at home did their test, they came out with 120mg per cup in their coffee. Read through the board’s thread on this if you like. I’m referencing more I find from using their comments as a guide for searching.
One such guided attempt took me to this page on the Center for Science in the Public Interest website. I like this table for comparing coffee with teas and other caffeine content drinks.
You can see why I’ve started drinking teas and other drinks on my Starbucks days.
From the abstract for a study done on specialty coffees, we have this:
“We evaluated the caffeine content of caffeinated and decaffeinated specialty coffee samples obtained from coffee shops. Caffeine was isolated from the coffee by liquid-liquid extraction and analyzed by gas chromatography with nitrogen-phosphorus detection. In this study, the coffees sold as decaffeinated were found to have caffeine concentrations less than 17.7 mg/dose. There was a wide range in caffeine content present in caffeinated coffees ranging from 58 to 259 mg/dose. The mean (SD) caffeine content of the brewed specialty coffees was 188 (36) mg for a 16-oz cup. Another notable find is the wide range of caffeine concentrations (259-564 mg/dose) in the same coffee beverage obtained from the same outlet on six consecutive days.”
You can find this here with a link to the full text of study below it.
By using this set of resources, you should be able to guess how much coffee is in your cup and find the safe amount for you to drink.
But remember, these are estimates. Even from the same source, caffeine amount can vary from day to day, due to different roasting times, brew times, variances in measuring, etc.
And if you’re super sensitive to changes in your caffeine levels, be aware there are sixty or so types of plant species where caffeine occurs naturally. You can find some listed here.
Enjoy your coffee and encourage better health by drinking responsibly.
Image Credit: FreeImages.com/Allison Choppick