<human>: Can you succinctly summarize the text in 1-3 sentences?

Is it possible for one type of coffee to have "better" caffeine than another? I have been drinking coffee daily for decades. Caffeine hasn't been doing much for me in the way of wakefulness or energy for a long long time. 

If I'm actually trying to use coffee to wake up, usually it's effects are: tired, tired, tired... Still tired... Overcaffeinated, nervous and edgy!

I had assumed this was just because I'm getting old and my tolerance has exceeded caffeine's inherent potency.

However, my wife and purchased a different brand of coffee bean than usual the other day and the energy it gives me feels really fantastic, without the usual edgy, nervous garbage. After two cups or so I feel really great. I actually get tingles. I can't remember the last time coffee did this for me.

Why? Isn't caffeine just caffeine? Am I crazy?
<bot>: Bought some new coffee beans that make me feel great instead of nervous and edgy. Why? What could possibly be the difference?