Sour on first pour

[davew]

Hello all,

I'm getting back into brewing after a year hiatus. I started back into brewing by moving from extract to all-grain. Previously I've been kegging extract batches.

After kegging my beers always seemed to pickup an "off" flavor. I was never able to pinpoint exactly what it was but I assumed it was the so-called "extract twang".

My first all-grain batch is the hex-nut brown ale from Midwest. I tasted before it went into the keg and it was great. I tasted again after a week carbing at 12 psi and it was awesome. After two weeks I started to taste a sour or acidic flavor. More specifically, the first pour is extremely sour (or maybe acidic?). Sequential pours seem to get better, but I still can't seem to kill the off flavor.

Instead of using my old taps I picked up a new picnic tap for this keg. I sanitized everything with start-san before kegging except for the gas line and 4 way manifold which has been sitting in the fridge for about a year since I last kegged.

I'm now 4 weeks from when I first kegged the batch and I'm still getting the same results. I'm curious is this is acidic bite, or some kind of infection? Should I santize the gas lines and manifold before hooking up my next batch?

 

[zachattack]

Is it a plasticky off flavor? Some people are sensitive to the vinyl flavors that can leach into the beer from the line. This will happen more with new lines and since it only affects the beer that sits in the line you'd probably only notice it on the first pour of the night.

If this is the problem, you can try swapping the beer lines for some of the barrier tubing like Accuflex. You will need about twice as much per line since most of us have found the resistance to be a lot lower.

But it's weird that you didn't have this problem when you last used the system a year ago. Did you buy new tubing with the picnic tap, or are you using the old stuff? If it's the old stuff maybe it is some funk in the line. Did you clean the lines, or just sanitize them? Try running some oxy/PBW solution in there and letting it soak for a few while, rinse very thoroughly with warm water, then sanitize, then hook it back up. Overcarbonation can also lead to a carbonic acid sourness like you're describing, but it doesn't sound like your beer is overcarbed...

 

[caver95]

How is your gas supply?

 

[FATC1TY]

I'm thinking your lines, or your sanitation with making the beer.

If it's over carbed it and get like that, but unlikely if you did a set and forget at 12psi

 

[davew]

I bought a new picnic tap with tubing and cleaned with one-step and sanitized with star-san by pumping it through the new line with CO2. I cleaned the keg with PBW, then one step, and then star-san. I removed all the drip tubes and let them soak in one-step as well and replaced all the gaskets.

I checked my fridge temp -- I'm using an old refrigerator -- and I was actually in the 35-37 degree F range.. so I'm probably getting some more carbonation due to the lower temps but I'm not sure if that's enough to be a factor.

Gas supply is full - I just exchanged my old tank for another.

As far as my previous batches - I always thought the odd flavor I was tasting was from the extract, but I'm starting to think that flavor is similar to what I'm getting in this batch.

 

[Bowtiebrewery]

So you said that your first pour is sour but it gets better after every pull after that... Now is that the first pour every time or just the first pour from the keg?

It wouldn't make any sense that one should taste better than the other or get better after the first pour if it was a sanitation issue. I hate to say it man, but somewhere in your keg, or lines, you have some sort of sanitation issue. If it truly is just the first pour and then it goes away, its your line or dip tube area...

A cheap way to know if your whole batch is impacted is to get a whine thief, sanitize it, depressurize the keg, take the top off and grab some beer out of it and put it in to a clean glass. If it tastes good then you know that its probably your beer line. To be safe I would go out and buy a new dip tube, post, gasket, fitting, and beer line completely and replace it. At least you know you are starting off 100% safe and clean.