I bought the Williams brewing aeration kit (link) and have been having fermentation issues ever since.
My old method of aeration was to cool and then transfer the 10.5 gal of wort into (3) portions of 3.5 gal each in 5 gal buckets, use a stainless steel whisk and beat the crap out of it. It was effective but time and labor intensive.
I now transfer the cooled wort from the kettle directly to the fermenters, submerge the wand and open the O2 valve slowly until I see O2 bubbles surfacing then stir the wand around for a timed 1 minute.
Since the change I get an active fermentation that starts as normal but slows dramatically after approx 36 hours. I take gravity readings on day 10, and 12 and if no change then rack to a keg on day 14. The last batch, an american amber, started at 1.053 and stopped at 1.020. This has been a typical result for my last 3 batches. I use mostly dry yeast SA04, 05 or Nottingham, rehydrated, 2 pkgs. I ferment in 2 Better Bottles.
This last brew I tried swirling the fermenters when I noticed the krausen dropping in attempt to keep the fermentation going.
The other thing I notice is a significantly smaller yeast cake left after moving the beer to the keg.
All other factors as far as fermentation environment haven't changed so my theory is the wort doesn't have enough O2 saturation to support the needed yeast reproduction to do the job.
How can I be sure I am adding enough O2 to the wort?
My old method of aeration was to cool and then transfer the 10.5 gal of wort into (3) portions of 3.5 gal each in 5 gal buckets, use a stainless steel whisk and beat the crap out of it. It was effective but time and labor intensive.
I now transfer the cooled wort from the kettle directly to the fermenters, submerge the wand and open the O2 valve slowly until I see O2 bubbles surfacing then stir the wand around for a timed 1 minute.
Since the change I get an active fermentation that starts as normal but slows dramatically after approx 36 hours. I take gravity readings on day 10, and 12 and if no change then rack to a keg on day 14. The last batch, an american amber, started at 1.053 and stopped at 1.020. This has been a typical result for my last 3 batches. I use mostly dry yeast SA04, 05 or Nottingham, rehydrated, 2 pkgs. I ferment in 2 Better Bottles.
This last brew I tried swirling the fermenters when I noticed the krausen dropping in attempt to keep the fermentation going.
The other thing I notice is a significantly smaller yeast cake left after moving the beer to the keg.
All other factors as far as fermentation environment haven't changed so my theory is the wort doesn't have enough O2 saturation to support the needed yeast reproduction to do the job.
How can I be sure I am adding enough O2 to the wort?