[ynotbrusum]

I am wondering if anyone has experienced this - I was racking from a low pressure fermenter to a keg using a closed loop set up (Speidel with spunding valve at 2-4 psi at late ferment - 10.5 gallon batch).  Fermenter to Keg out post flow direction and keg gas post to top of fermenter gas post).  The spigot to keg line was clear tubing, so I could monitor the flow.  The first 5 gallons flowed to the keg without incident, but then about midway through the second five gallons, the tubing developed enough CO2 release from solution to become "blocked" for the flow of beer.  I lifted the keg up to allow for the CO2 to clear the line, but the same thing developed a bit later.  So, it became a very slow racking to the keg.  I experienced this once before with a Belgian Tripel that I rushed to finish (for contribution to a club barrel project) and it had not off-gassed.  This time it was a Pilsner that I intentionally carbed a bit at the end of fermentation...any thoughts on this situation?  I know I won't encounter the issue on the Kegmenter set up that I now also use, but I hate to put other fermenters out to pasture for fear of this recurring. Cheers for any insights or process suggestions.

[Robert]

Hmm.  Never encountered that when I used a Speidel.  I did find racking by gravity in a closed loop painfully slow, because only so much can squeeze through that little poppet on the keg post without pressure assist.   So I tended to rack with a little head pressure from a gas bottle on the fermenter, and a gas tube off the keg into a bucket of iodophor.  (Same system I now use with my 10 gallon corny.)  Might that keep things moving in your situation, either preventing gas breakout or at least  carrying the bubbles along?  I know it's not as elegant as the closed loop, and Speidels can only take a few psig,  but that's plenty to get the job done.  If atmospheric pressure on the keg would just encourage breakout,  you could use that spunding valve on the keg for a controlled counterpressure transfer that might do the trick.  Just be careful to stop before beer squirts out the spunding valve. 

[kramerog]

Thee phenomenon being described appears to be something that happens when racking slowly using a siphon.   Beer in a siphon above the top of the beer in the fermenter is under vacuum encouraging bubbles to form.  Most of the time, the flow is fast enough to sweep the bubbles out.  But, when the flow or beer slows down as the elevation difference between the top of the beer in the fermenter and the top of the beer in the keg gets smaller, the likelihood of a large gas bubble getting stuck in the racking line gets bigger.  I find that keeping the bottom of the fermenter a few feet above the top of the keg prevents this.

[ynotbrusum]

I think both of you make valid conclusions. The bottom of the fermenter was about 8-12 inches above the top of the keg and the head pressure assist was something I resorted to but I ran out of patience.  I racked the last half gallon into a 2 liter soda bottle and carbed it overnight while it cold crashed.  It turned out excellent for the small carbed portion, so I expect the kegged portions to be equally tasty.

I have a batch in the Kegmenter (made Saturday) that I will allow to naturally carbonate by spunding the primary when there are a few gravity points remaining (using Tilt device !).  I know that I can push with CO2 from that vessel with no problem just like when I transfer a bright tanked completed beer to serving kegs.