Purge picnic tap line

[Alf34]

Hello

I was wondering if you need to purge your picnic tap line.

My usual process after transfering the beer using a semi closed transfer, is setting the regulator to 12 psi, putting the keg in the fridge, and finally connecting the picnic tap that has been previously sanitized with star san.

I basically run star san through the picnic tap using CO2, quickly disassemble the tap and then dump all the sanitizer left in the line. Then I reassemble the picnic tap. When the keg is in the fridge, I connect it to the keg.

Yesterday I noticed, when connecting the picnic tap, that some beer was leaving the pressurized keg, and then slowly being sucked back into the keg. Is there a risk of oxidation since that line was somehow full of oxygen?

 

[mac_1103]

I basically run star san through the picnic tap using CO2, quickly disassemble the tap and then dump all the sanitizer left in the line. Then I reassemble the picnic tap.

Why not blow the starsan out with CO2? Or just purge the line with beer as soon as you connect it.

 

[hottpeper13]

I keep a 2.5 gal starsan keg and I just fill the line , disconnect it and connect it to my serving keg and just dump the first 1 or 3 pours. You can't leave starsan in the line or it will turn cloudy. I have a tap on my keg washer for line cleaning and after a rinse I leave it empty, then sanitize just before using.

 

[Alf34]

Do you think there is risk of oxidation considering the method I used?

 

[sibelman]

just purge the line with beer

This is super easy.

risk of oxidation

There's always going to be a wee bit of air that can't be eliminated, e.g., inside the quick disconnect junction. But taking simple steps to minimize air (~21% oxygen!) ingress just makes sense.

slowly being sucked back into the keg

Is it possible you need a new picnic tap? It ought to seal well enough to prevent suck-back, no? (I use the tap from Homebrewer Lab ($25 on ebay.com), so can't see any suck-back - but I have no reason to think it's happening.) If the line was full and the tap itself isn't leaking, then the "air" you're seeing is probably all CO2 that's coming out of your carbed beer.

I still sometimes forget to purge my transfer line, but purging it with beer while attaching it to the serving keg has become part of my standard practice. Every little bit helps hurts, especially with hop-forward beers and also with beers that won't be consumed quickly.