You might notice that many Coffee products are lacking a core coffee nutrient in our database - caffeine. This is because a lot of vendors do not indicate the amount of caffeine in their nutrition facts. Thus, the caffeine amount appears as N/A for these products. We respect the integrity of nutrition facts provided by vendors and do not change or interfere with them in any way.
That does not mean that you cannot consistently track caffeine, however. Users can use their own discretion and add the caffeine amount to the coffee you want to use in your food log with Copy & Customize Food tool. A new custom food will be created based on the selected food, which you can subsequently edit to enter the caffeine amount you've estimated for this type of coffee. This tool is available at the bottom of the Food Entry screen in the iOS app and on the Food Label screen in the Android app (named Customize).
You can use this great and informative Mayo Clinic article as reference when adding caffeine amount.