Sorry to disappoint all you aging hippies but in reality maté has very little caffeine compared with even a half decent black tea.
Pomilio et al (in Phytochem 13(4):235-41. 2002) tested 14 brands and bulk maté and found caffeine levels of 0.78 to 1.35% on a dm basis (steeped for 5 minutes). Equivalent for a typical UK black tea blend is 3%. Maté theobromine was a tad higher than tea at 0.31 to 0.66% but even combined (their physiological effect is similar) maté could only boast 2.01% of "thunder" - more a "morning zephyr" compared with a Kenyan clonal at 5-6% caffeine.
True that, like coffee the caffeine in maté is "raw" and its effect is not softened by the counterbalance of polyphenols and theanine as it is in tea. But as for its thunderous performance I suspect the power of Celestial's advertising rather than the much hyped but totally incorrect myth about the caffeine content of maté.
Incidentally the work of Pomilio is not alone in showing a low caffeine content for maté. Filip et al (1998) showed 1.9% (boiled in water for 20 minutes) and Saldana et al (2002) showed just 0.3-0.6%
Nigel at Teacraft
---------- Forwarded message ---------- From: snipped-for-privacy@virginia.edu (David Sewell) Date: Jan 24 2004, 9:36 pm Subject: When did Morning Thunder lose its buffalo kick?
I've purchased Celestial Seasonings' Morning Thunder tea off and on over the years, since the days when it was nearly the only bagged tea with yerba maté that you could find in the U.S. I had always vaguely remembered that a bag was supposed to have the caffeine content of a cup of drip coffee, around 100 mg. And a Google search of old Usenet postings shows that it had the reputation of being even more potent, or perhaps nefarious; the FDA and/or one or more states were rumored to have banned it sometime in the early '90s. (I do remember it went missing from the shelves for a while.)
Whatever the case in the old days, it's currently simply a blend of roasted maté and black tea. And according to Celestial Seasonings' website, an 8 oz. cup contains 40 mg of caffeine, significantly less than the 65 mg in a cup of their pure organic black tea.
I'm pretty sure that the original formulation had added caffeine to bring it up to coffee strength. Does anyone know when it changed? (The amusing thing is that some of the recent Usenet postings are still referring to it as if it were a dangerous drug... I wonder if any aging hippies furtively stick it in their shopping carts when no one else is looking, feeling mildly guilty...)