Beer line...um...zest?

[ftlstrings]

How often do you all replace your beer lines in your kegerators? I haven't had any problems until now, but I think that I may have something up with my beer line. It's not more than 2 years old but I have noticed a definite taste that is way off-putting in my first pint pour from some of my lines lately. Thought I had infected beer, but think that it may be my lines since the taste, sorta like dirt and old soggy cardboard, goes away after the first pint or so. Didnt notice until I tapped half of my Centennial Blonde batch.

Any thots?

~M~

 

[IffyG]

How often are you pulling a pint? I've got 10' lines and the first 3 ounces or so pick up a plastic like taste if I don't pull a pint for a few days.

 

[WrongCoastBrewery]

The best thing to do is to check the shelf life of the tubing. Anything plastic or rubber has a shelf life and after a while, the tubing will start to break down especially if it isnt cleaned regularly. Between microorganisms growing in the tubing and (depending on the humidity and temperature) natural breaking down, tubing will go bad eventually.

 

[ftlstrings]

well, between me and the neighbors, the beer doesnt sit in the lines for too long. I have 10' lines as well.
The temps stay in the low 40s all the time and the humidity is controlled by damp rid so it shouldnt fluctuate too much..


~M~

 

[funkswing]

What beer lines are you using?

I think that oxidation occurs in beer lines b/c of the surface area to vol ratio when in the lines. Plastic is gas permeable to some degree, the better the Bev line the slower the rate is going to be. But b/c the beer has a lot of exposed surface area, the slow rate of oxygen diffusion thru the bev line is easily overcome by the overnight/day hours the beer sits not moving.

I think that most people taste oxidation in there first 1-3 oz pours when the beer sits in the lines for a while, with the "plasticy" taste either being merely perceived (b/c you know the beer is in a plastic line) or is only a small portion of the "off flavor".

You said it best:

think that it may be my lines since the taste, sorta like dirt and old soggy cardboard, goes away after the first pint or so.

Cardboard = oxidation

 

[ftlstrings]

hrrm... Makes me wanna do some kind of experiment.

 

[ftlstrings]

It seems a bit counter intuitive since lots of people add O2 to their wort pre-yeast pitching, but can aerating wort cause that darn flavor?

~M~

 

[philrose]

O2 is added at one time for yeast health in reproduction, nearly any other time and you won't have the activity of fermentation to negate oxidation off flavors, think cardboard and cream sherry. Those are commonly associated with o2 in a finished beer

 

[ftlstrings]

Cool wort that is, less than 80 degrees

 

[funkswing]

It seems a bit counter intuitive since lots of people add O2 to their wort pre-yeast pitching, but can aerating wort cause that darn flavor?

~M~

Like was said, O2 added pre-fermentation is used by the yeast (they "breath", respire, like us). So the O2 isn't available to oxidize the beer after the yeasties use it up (and create CO2, just like us).

But after fermentation, if you aerate (which is now simply called oxidation, b/c it is viewed as a negative thing for the final beer product), you will be oxidizing the beer, which leads to this "cardboard" or dry flavor in the beer. The flavor is pretty off-putting, like drinking a warm, old can of Bud.

Aeration good (pre-fermentation), oxidation bad (post-fermentation).

 

[ftlstrings]

Check. I dont aerate post ferment, save for a little when siphoning probably (incidental O2 transfer before the beer level in the keg covers the end of my siphon hose). I should prolly spend more time purging my kegs with CO2 pre transfer.