Thanks! So, we started out with the intent to clone Club Mate, but then sort of went off in a different direction- to me, it was more interesting to try some different flavors. I’ll agree that it is probably even more interesting to start with base materials (though the chai mix we used was pretty tasty). Also, we drank up our entire shipment of Club Mate, so someone has to order some more if we want to do taste comparisons.

It’s possible that they didn’t need to add caffeine, but the calculations we did using the recommended volume amount of tea showed that it needed to be supplemented. Wikipedia says that it has 20 mg caffeine per 100 ml of liquid (http://en.wikipedia.org/wiki/Club-Mate), where our three grams of input tea (which was already mixed, so the actual mate content was lower) wasn’t enough to hit that amount (using http://www.erowid.org/plants/yerba_mate/yerba_mate_chemistry2.shtml for an estimation of the caffeine delivered by a hot-water extraction method). I suppose the other option is to use boiling water (needs taste test), or just more tea/volume. Also, now that we have the powder, we can use it to make other things such as caffeine jello shots

“I am not sure why you are adding caffeine powder. I’m certain that the original producers of Club Mate didn’t have to add this.”

The club mate bottle I have indicates “Mate soft drink with caffeine” and “Increased concentration of caffeine (20mg / 100ml)”

That’s sort of ambiguous, but my reading of it is that they have indeed added some extra caffeine to the mix, in addition to what one would get from the tea itself. Additionally, they do list caffeine as an ingredient, separate from the mate extract.

That said, I may skip the extra caffeine when I make my open mate batch… but that’s just because I like the taste more than I like the stimulating effects.

This looks like a really cool project. I’m a big fan of Club Mate and I’ve even tried making it myself (without much success). Two things I noticed though are that:
1) the mate tea you are using is already blended with some things that give it flavor. I might recommend using plain mate tea, such as “Guayaki Traditional Loose Yerba Mate” (available at places like Whole Foods). I figure this would get you closer to Club Mate, which is pretty plain.
2) I am not sure why you are adding caffeine powder. I’m certain that the original producers of Club Mate didn’t have to add this. Maybe by brewing it longer or with more mate, the caffeine level of Club Mate can be achieved.

Good luck with future batches !

Anyways… I’ve never had Club Mate, but am intrigued. As a beer brewer and ginger beer creator I’m interested in any sort of fizzy beverage that’s a little odd and perhaps unpalatable to the masses. So, I just bought a case for my new hackerspace (Interlock Rochester http://www.interlockroc.org ) and I’ve got some mate and powdered caffeine on the way. I’m thinking our first batch will use some lemon juice or citric acid to add that little hint of acidic bite… I’ll keep you updated. Please let us/me know when you’ve got more documentation up!

Just as there are open source beer recipes, open source cook books, etc., we want to open up everything about Open Mate and share the improvements with everyone who cares. We’re going to try and get better web presence and documentation going shortly, so stay tuned!

Or, alternatively, explain what the difference between “Open Source Soda” and “A Recipe We Posted On The Internet” is.