In the United States federal regulations require that in order to label coffee as “decaffeinated” that coffee must have had its caffeine level reduced by no less than 97.5 percent. So how much caffeine is in decaf coffee? Anywhere from 0.1% to 2.5% depending on the decaffeinating method
Example: Panamanian coffee is about 1.36% caffeine by weight normally. This and many other Arabica coffees are about 98.64% caffeine free even before anything is done to lower the caffeine content. This is because the other components that make up the coffee bean (cellulose, sugars, moisture, chlorogenic acids) are primarily what give coffee its flavor.
When 97% of the caffeine has been removed only (1.36% / 97% =) 0.0408% of the coffee caffeine by weight. About 4/100ths of 1%. At this level it is labeled “decaffeinated”. How roasters label their products is another matter. Suppose two roasters roast Panama coffee that originally came from the same lot, and were decaffeinated together in the same vat. One roaster labels his decaf. “97.5% Caffeine Removed.” The other says his is “99+% Caffeine Free.” Which roaster is not telling the truth?
The answer is: They are both right. One is talking about the removal of caffeine as a percentage and the other is talking about the amount of caffeine compared to the weight of the coffee. They are both essentially saying the same thing, albeit using vague and confusing terminology.
Taking a 10 gram serving of coffee (10,000 mg) and dividing it by 0.0408% gives you just over 4 mg. Decaf should range somewhere in the 2-4 milligrams of caffeine per cup range. Note that a “cup” here is referred to 6-oz of brewed coffee, far less than what is typically consumed.
Currently used solvents for decaffeinating coffee include, H2O (water), CO2 (Carbon Dioxide), Meth. Chloride, Ethyl Acetate. Note: A relatively new method called Swiss Water Decaffeinated uses “flavor-charged” water in the decaffeinating process.
Generally, the Swiss Water Process is used for coffees that are well liked and used in a lot of blends, from countries that produce a lot of coffee. Colombian coffee is by far the most popular, with Peru and Kenya sometimes being available depending on the crop and feedback from wholesale coffee buyers.
Caffeine in Starbucks Decaf Pike Place Coffee
Starbucks lists the following caffeine levels in their Decaf Pike Place Roast:
- Short (8 oz): 15mg
- Tall (12 oz): 20mg
- Grande (16 oz): 25mg
- Venti (20 oz): 30mg
It should be noted that these are estimated values based on average readings – Starbucks coffees are blends of many different coffees and crops vary from year to year.
Comparing a 16-oz decaf Pike Place (25 mg) to a 16-oz regular Pike Place (310 mg), you get about 8% caffeine remaining, or 92% decaf. While this is a significantly decaffeinated drink, 25 mg is still a good amount of caffeine.