Welcome back apegrape!
I thought I remembered Uny telling about how she uses the root beer herbs so I couldn't stop looking until I found it lol! Here you go.
Blessings,
Willow
So, in ever 10 cup batch (using RO water), I add:
1/2 lemon (unsqueezed, scrubbed thoroughly to remove any pesticides on the surface if non-organic)
2 dates
1-3 teaspoons blackstrap molasses (generally a teaspoon and whatever 'spills over')
1 pinch of baking soda (I don't like the taste of more than a pinch)
1 heaping 1/3 - 1/2 cup of Turbinado (any high quality evaporated cane juice)
As far as fizzy? We may open the jars several times in 48 hours just to check for fizz/life (and to let some out if the top of the lid was becoming 'domed'). Yeah, letting it out does ultimately effect how fizzy it is in the end.
HOWEVER...we don't really care for the taste of "plain kefir", so we always do a second fermentation (usually in the fridge)...with the addition of a wee-bit more sugar, a tablespoon or two of grains and a chopped/sliced vanilla bean (or the root beer herbs). To ensure "fizzy production", we take the jars out of the fridge several times during that two days and let them 'warm up' to room temperature a few times (if needed). Then, to ensure maximum fizzness (if we've got the time and room in the 'fridge) we'll put it into individual bottles after straining out the bean or herbs).
We just got 12 of these (!!!!!! woohoo !!!!!!) for our kefir bottling:

http://www.specialtybottle.com/index.asp?PageAction=VIEWPROD&ProdID=116
They're absolutely PERFECT for kefir (only 8 1/2 ounces); very thick/safe glass, and we can easily drink the entire "bottle's worth" at one time (no opening/reopening all the time that let's out the fizzy).
Also, I keep a bottle of 'sugar syrup' in the fridge (made from two cups of Turbinado and one cup of boiling water) - so if I need/want to add a tiny 'squirt of sweetness' (to feed the kefir or just because it got too 'tangy' for my taste) at any time, the sugar is already pre-dissolved and mixes in easily.