It's really interesting that there doesn't seem to be a solid definitive answer. I'm extremely sensitive to caffeine, but I love the flavor and wish i could enjoy all the wonderful coffee porters/stouts. From experience I feel there is quite a bit of caffeine in these beers. Two Left Hand Milk Stouts one evening and I did not sleep for even a minute. I enjoyed drinking them though! And that's not even a "coffee" beer, it's just one of the flavors. Not to make things complicated, but who else thinks there should be a caffeine content on the label of these types of beers? Some seem to have way more than others. It makes sense, especially for those of us sensitive to caffeine, to be able to make an informed decision when selecting a beer. Just my two cents!