I recently brewed my first batch of beer which was a brewers best RIS kit. The kit had been sitting around for about a year and a half. I brewed it two weeks ago now. The kit came with nottingham dry yeast, before pitching i rehydrated per the instructions on the packet in 90-100F water 30min prior to brew and pitched it at the same temp as the wort. Now, after two weeks, i took a gravity reading and the beer is at 1.030, starting was 1.074, which doesn't seem like a very good attenuation rate. The air lock hasn't had any movement (glass carboy) in a while, i tried giving the carboy a little shake to stir the yeast back up but am still not getting any airlock activity. As far as aerating the wort before pitching, i transferred the wort to the carboy by pouring from the kettle through a funnel which whipped quite a bit of air into the beer, i didn't bother to shake the carboy beyond this but looking back maybe it wouldn't have been a bad idea. The things i was wondering about where:
Could the low attenuation be caused by the yeast being over a year old?
Will pitching another packet of yeast help things out?
I have read around of people using aquarium pumps to aerate their beer, does anybody have experience with this? Am i right in assuming that there might be the potential for infection with this method, pumping external air throught the wart. Or, is there some kind of filter?