Caffeine in Coffee Beer?

I've never experienced any effect from coffee beers but I rarely go a day with a cup or two of coffee. I think you'd have to be extremely caffeine sensitive to get anything.

I just added around 8 ounces of pretty strong cold brew concentrate to 2.5 gallons of a home brew porter. It would be roughly .3 ounces per 12 ounces so while the coffee flavor will be prominent (hopefully), there won't be caffeine as it is so diluted.

 

I don't know what proportions of coffee to beer most commercial breweries are using for their coffee beers, but I think it's entirely possible there is more caffeine in some of these beers than you may think.

I'm a beer geek first and foremost, but I also consider myself a bit of a coffee geek. I don't have any scientific numbers or measured data, but did some quick back-of-the-envelope type calculations:

As far as I know, all coffee added to beer is cold steeped in some way; I've never heard of anyone adding hot brewed coffee to beer, since cold brew is smoother and easier to work with for brewing purposes. Modern Times recommends a ratio of 12 oz coarse ground coffee to 7 (8 oz) cups of water for cold brew coffee. I've heard of homebrewers using up to 8 oz of whole coffee beans per 5 gallon batch. Given MT's ratio, that would give us ~37.3 fl oz of cold brew concentrate. Added to 5 gallons (640 oz) of beer, that gives us about a 5.8% concentration of coffee. That comes out to almost 1 fl oz (of strong cold brew coffee concentrate) per pint of beer.

Keep in mind, that cold brew is generally more caffeinated than coffee brewed by other methods (due to longer extraction times), all other things being equal. In particular, this is very strong cold brew; one 12 oz can of MT cold brew is enough (poured over ice) for me, a daily coffee drinker) to sip on over the course of an entire 8-hour workday, and I feel overcaffeinated, even if that is the only caffeine I consumed that day. For comparison, in my French press, I would be able to make ~15 8 oz cups of coffee with that same 8 oz of beans that would give us a ratio of ~18% coffee in a 5 gallon batch. That's ~2.8 oz of (strong French press) coffee in a pint of coffee beer. Traditional drip coffee is typically even weaker than that, so I wouldn't be surprised if either of these scenarios are approaching the caffeine levels of a traditional 6 oz cup of drip coffee.

Of course, caffeine content is very dependent on the coffee variety, growing region, conditions that growing season, roast level, and whether it has been decaffeinated or not - all in addition to the variance due to brewing method. I'm not advocating against coffee beers, we're all adults who can make our own decisions, and they are delicious. I'm just saying that there very well may be significant caffeine levels in some coffee beers. The more you know...

 

This is in line with the only coffee beer I have brewed. It comes out to ~2.5% coffee. I added 2 oz of beans to a 2.5-3 gallon batch of blonde ale. That is roughly equal to your 8 oz of cold brew, if you used the ratio from MT that I provided in my last post. I tasted coffee, but I'm not sure I felt the effects of caffeine. Of course, I never drank more than one in a session, and I avoided it at night on principle. Next time, I'll probably add more coffee.

 

I'm curious to see if it has any effect, I'll try one on a weekend morning before I have any coffee (for science, of course).

 

What keeps me up is the sugar (alcohol) in big coffee beers (anything over 8%), not the caffeine.

 

MAYBE a slight headache. I've had hospital stays where I didn't drink coffee for several days. It wasn't much of a problem.

 

Same here. Drank a pint of Speedway yesterday evening and very hard to sleep after.
Never felt the same with other coffee beer like kbs, coffee oki...