My roommate got a Sodastream for Christmas this year and out of morbid curiosity we tried it on my Hefeweizen, which I bottled tonight. It worked well. It wasn't quite the same as a nice bottle conditioned or kegged home brew, but it beats the hell out of tasting the un-carbonated leftovers from your FG measurement. We filled one of the plastic bottles with the beer and gave it three charges of CO2 (same as the recommended dose for soda which, incidentally, seems to leave the soda a bit flat ), then capped it and chilled in the freezer for 30 minutes or so. I don't know if I would consider it as a permanent carbonation tool, but it provides some instant gratification on nearly finished beers. Also, we discovered that the thread on the soda bottles appears to be the same as the thread on 1/2 gallon and 1 gallon growlers. With the SodaStream fully assembled, neither growler size fits under the machine (the bottles are too tall), but with some modification we could make it work. I think we will probably come up with a solution for the next beer I make. As was mentioned in an earlier post, disconnecting the bottle from the machine after carbonation requires some finesse to avoid an explosion, but with a bit of care we spilled less than an ounce of foam.