How much caffeine do you get from coffee beans?

[Calder]

I added 1 ozs of whole beans to 2.5 gallons of a Porter last week. The beans were in for 6 days before bottling.

1 ozs of coffee doesn't seem like much, but there was a lot of coffee flavor. Six days to steep coffee vs 10 minutes in the coffee maker. A lot more caffeine has to have been extracted, but you can only get so much from a bean.

Just wondering. How much caffeine do you think would be in one of my 12 ozs beers, versus using the same coffee beans (ground) to make regular coffee?

 

[derek704]

What type of coffee did you use? You probably aren't getting much, but I could give you a ballpark max that could be in each bottle. Did you add it after the boil?

Without knowing, here is an example:

Espresso, restaurant-style coffee 1 oz contains 47-75 mg caffeine. IF for some crazy reason you reached those numbers of caffeine without heating the beans, and if you get 26 bottles from your batch, you could have at MOST 3mg per bottle. Compared to a 12oz Coke, which contains about 34mg.

 

[Calder]

What type of coffee did you use? You probably aren't getting much, but I could give you a ballpark max that could be in each bottle. Did you add it after the boil?

Without knowing, here is an example:

Espresso, restaurant-style coffee 1 oz contains 47-75 mg caffeine. IF for some crazy reason you reached those numbers of caffeine without heating the beans, and if you get 26 bottles from your batch, you could have at MOST 3mg per bottle. Compared to a 12oz Coke, which contains about 34mg.

It was just a French Roast Coffee. Whole beans steeped for 6 days.

After reading your post, I did some research (google). It was hard to find real information, but it seems there maybe around 300 mg of caffeine in 1 ozs of beans. I was looking up how much caffeine you could get if you eat the beans. I did find one reference that put the caffeine way north of that number. I think your 47 - 75, is the amount of caffeine extracted by the expresso brewing process.

Caffeine is supposedly pretty soluble, but I have no clue as to how much is extracted during cold steep. If the 300 mg number is correct, and I assume I get 90% extraction, I would have roughly 10 mg per 12 ozs beer (I got 26 bottles).