As if I needed more reasons not to drink caffeine, it has a half-life in full-term newborns of around 95 hours, infants 80 hours! (The range is 65 to 130 hours.) Yowzah! The peak transfer to breastmilk is 1 to 2 hours later. Half-life indicates a decay pattern that starts with a large initial peak, then tapers off slowly. The half-life is the time to purge half of that caffeine, but there's still a long tail on the curve: after two half-lives, 25% of the original caffeine still remains.
So this afternoon when it was so hot and I was walking back to my office past the old-fashioned convenience store, I got the caffeine-free Pepsi (less acid than Coke). I don't know why this baby is awake at 11 PM, but at least I know it's not because I should have skipped caffeine.