Wants to be hyper-rational and metric-aware about his sleep but didn't know anything about caffeine?
Okay.
Wants to be hyper-rational and metric-aware about his sleep but didn't know anything about caffeine?
Okay.
http://www.mayoclinic.com/print/caffeine/AN01211/METHOD=prin...
Espresso, restaurant-style 1 oz. (30 mL) 40-75 mg
Generic brewed 8 oz. (240 mL) 95-200 mg
The brewed coffee thus has between 11.9 mg and 25 mg of caffeine per oz.
If you added a shot of espresso (let's assume the weakest one at 40 mg of caffeine) to an 8 oz of very strong coffee (at 200 mg of caffeine), you'd still be increasing the concentration to ~26.7 mg/oz.
And that's stretching the limits of these calculations; a 200 mg 8 oz coffee is crazy strong, amounting to two and a half cans of Red Bull.
Can I just halve the time required if tea has half the caffeine (let's say)?
If you're in the US, the Stash decaf range is IMO the best of the common supermarket brands (the normal American teas like Lipton and Tetley are pretty terrible in their decaf versions). If there's a gourmet store around, they may have the English brands such as Typhoo or PG Tips in decaf, which are pretty great. If you're in the UK then any advice on tea from the likes of me should just be ignored out of hand... :)