Just finished up a batch with Safale K-97 and was disappointed by the lack of information on the web before I brewed, so I thought I'd add to an old thread in case anyone goes searching...
I fermented at 60* to 62* for a three week primary. The fermentation only lasted 15 days, however, although the OG of the beer was 1.075, so it should be expected that the fermentation dragged on a bit. The actual attenuation rate was 76%, though the yeast in suspension initially gave a false rate of 71-73%. (Yes, the yeast flocculates poorly enough to impact the final gravity measurement by several points.) The krausen was excellent, as others have reported, and I got a nice, bready smell from the airlock that gave way to a fruitier pear and banana-like smell as the fermentation progressed. After the three week primary--when I would usually bottle--the beer remained extremely cloudy due to the yeast that remained in suspension. I mean, clumps of yeast were still floating at the top a week after the fermentation had finished out. There was still airlock activity also, which should emphasize the fact that you need to rely on gravity readings only! At this point, the hydrometer reading read 1.020. I crash cooled the beer at this point and stored it at 45* for 10 days. About an inch of new trub formed in the process. The beer was re-seeded during bottling. The resulting beer was fairly clean and well-attenuated, though it had a tangy finish and a slight pear ester. The yeast is supposed to be an alt yeast, and I think it would make a great alt or kolsch. That said, the yeast was kind of a pain to work with compared to Safale S-05, which I think it could be easily compared to or even mistaken for.
*Notes: This is based off of only one batch. I used it in a maibock, so while it definitely stretched the style, I recorded careful measurements and got some useful insights into the character of the yeast.
