Did I Mess Up My Keg Purge?

[chewyheel]

For my latest batch, I made a Vienna lager that I have made a few times before, so I knew what flavor to expect. However, this was the first time I have purged my keg using via the method of filling with with StarSan then pushing it all out, then racking the beer into it via a closed transfer.

It tasted and smelled fine when I sampled it from the fermentor, but a week later when I took a pull from the keg it was drastically different. Gone was the nice malt aroma and in its place was an aroma that I can best describe as 'chemical/plastic' and slightly reminiscent of StarSan. The beer also has a bitter finish, but not in a good crisp way that you'd expect from a lager. It's more of a lingering bitterness with a slight harshness to it.

Somehow from the fermentor to keg, I screwed up but not sure how. I'm thinking either some StarSan got left behind or my keg or tubing wasn't properly sanitized and some bugs got in for the ride. Anyone else experienced something like this before?

 

[day_trippr]

Between suck-back and short term memory loss, lots of folks have managed to mix as much as a quart of Star San mix in a keg of beer, and best as I recall nobody actually could detect it. And I just popped the lid off my 5 gallon Star San reservoir and I'm not smelling anything.

Something else is going on, imo...

Cheers!

 

[LittleRiver]

What kind of beer lines are you using?

 

[mongoose33]

It's not the star-san.

When I purge a keg using the star-san method, toward the end when the OUT line starts sputtering, I remove the OUT quick disconnect. That leaves the keg under some partial pressure. I attach a line with a QD to the OUT post, and blow out any remaining star-san. With a torpedo keg, which has the dip tube at the end, I tilt the keg so any remaining dregs of star-san collect under the dip tube and are blown out. With a center-dip-tube keg, I just rock back and forth a bit while it's upright.

If you haven't tasted star-san, do so. It's just phosphoric acid, in a concentration similar to what you get in Coca Cola. I'll bet you find it tasteless, and odorless. If not, try replacing your 11-month-old batch of star-san.

 

[VirginiaHops1]

I was cold crashing 2 batches a couple months ago and stupidly didn't pull my blowoffs because I was 'only' soft crashing to mid 50s and didn't think there'd be a ton of suckback. Oh yeah it all got sucked back. Probably a quart of star san if not more, into 3 gallon batches. No off flavors though, beer was good. Might've dropped my FG a point or two though. That said I don't use star san to purge my kegs. I give them a quick rinse with star san to sanitize but then I fill and purge with regular tap water.

 

[chewyheel]

What kind of beer lines are you using?

I’m using silicon tubing. Based on what others have said it must be some type of infection I believe. I will give my lines a good cleaning though before using them again as well as my keg.

 

[kh54s10]

I've never detected any odor when using Starsan, diluted or undiluted. But if you spray it in a fine mist then get a whiff.... No smell, but very unpleasant....

 

[LittleRiver]

I’m using silicon tubing. Based on what others have said it must be some type of infection I believe. I will give my lines a good cleaning though before using them again as well as my keg.

Silicon is used in brewing where hot liquids need to be moved, but it is not the right material to use for serving. Silicon has a high oxygen permeability compared to other options.

Try switching your beer serving lines to BevSeal Ultra 235. Use of John Guest fittings with that tubing is highly recommended. They make setup and changes so easy.

Also look into doing closed transfers from fermenter to keg. It's a simple way to keep your beer from becoming oxygenated (staled) while in the keg. Some people do closed transfers with pressurized CO2, but I just use gravity.

 

[mongoose33]

Silicon is used in brewing where hot liquids need to be moved, but it is not the right material to use for serving. Silicon has a high oxygen permeability compared to other options.

Try switching your beer serving lines to BevSeal Ultra 235. Use of John Guest fittings with that tubing is highly recommended. They make setup and changes so easy.

Also look into doing closed transfers from fermenter to keg. It's a simple way to keep your beer from becoming oxygenated (staled) while in the keg. Some people do closed transfers with pressurized CO2, but I just use gravity.

I switched to Bevseal tubing as you note; I had thinwalled tubing in the keezer and if the beer sat for a while, that first amount out of the tap was NG, in the extreme.

So the Bevseal. What I've found is that because it's so stiff, it actually makes it harder for me to add and subtract kegs. Much stiffer than regular vinyl or other tubing.

How are you using it? Maybe there's a trick here of which I am unaware....

 

[LittleRiver]

...Bevseal. What I've found is that because it's so stiff, it actually makes it harder for me to add and subtract kegs....How are you using it?...

I routed my Bevseal beer lines around the inside of the collar, for two reasons. First reason was to get them out of the way, since my keezer is small. I did not want to hassle with stiff coils of tubing when changing kegs. I use short shanks (2") with 90deg John Guest shank adapters, for the same reason (to keep the lines out of the way).

Second reason was to optimize cooling of the lines. I have a fan in the bottom of the freezer, blowing upward. The cold air can freely circulate on all sides of every inch of the lines. I think I get better cooling than if I just coiled them up and stuffed them somewhere (though I have no measurements to verify that).

This is an unconventional approach, but it has worked very well. Kegs are a breeze to get in/out. I get great pours with only 7' of beer line (the calculators say I need 12').

 

[Robert65]

An alternative to Bev Seal Ultra is EVA barrier tubing. It is much more flexible, almost like conventional vinyl (smaller diameter helps,) with the same gas barrier and microbe resistance properties. Also uses the same kind of push fittings. It comes from Australia, but is available through William's and MoreBeer. I've just switched everything over, so I can't report long term results yet, but in my research I saw that a lot of people have had better results in terms of longevity and cleaning and maintaining the lines than with Bev Seal Ultra, and it's very easy to work with. It also provides greater restriction, and therefore much, much shorter beer lines are needed compared to Bev Seal.