[jshark]

I just finished brewing up a batch of CREAM SWILL from Denny Conn's article in Zymurgy. I kegged it and am waiting for it to fully carbonate but, the flat beer tasted a bit tangy or cidery when first sipped. I've been brewing for several years and this flavor is new to me.

This is the first batch that I've used a plastic fermentor and dry yeast (Safale American US-05). Could the plastic or yeast be the reason? Have I been infected by bacteria? Anyone know what causes this off flavor?

[dmtaylor]

It might be a Lactobacillus infection.  It's happened to me.  I once made a Lacto beer on purpose, then several batches afterwards using the same equipment unintentionally ended up with Lacto infections as well.  Does the sourness taste like yogurt?  Sour cream?  That sort of tanginess?  Do you have any beer-loving buddies and/or local beer judges who would recognize what Lacto tastes like?  They should be able to tell you for sure.  If it is Lacto, then your plastic equipment is most likely permanently infected and will need to be replaced.

If it ain't Lacto... I can't really help you without tasting the beer myself.

[jshark]

It's a little yogurt-like.

Now that it's carbonated the smell has intensified and I'm wondering if it's the extra Columbus Hops I added. The beer is drinkable, but not...right. I may have to take a sample to the experts down the road at the local brew pub.

[anthony]

Is the beer clear? Fizzy yellow beer is even more impacted by yeast still in suspension than other styles.

[denny]

It's a little yogurt-like.

Now that it's carbonated the smell has intensified and I'm wondering if it's the extra Columbus Hops I added. The beer is drinkable, but not...right. I may have to take a sample to the experts down the road at the local brew pub.

I've made a lot of batches of that using 05 and a bucket, so I don't think that's the problem.  Adding Columbus is gonna overwhelm the other ingredients in that beer.  I wouldn't have recommended doing that.  How long since you brewed it?  What was the fermentation temp?

[jshark]

I brewed it 3 weeks ago...5 days in plastic- the rest in glass carboy all at 66 deg.

I also upped the six-row to 2 lbs. I suppose this is what I learn from messing with a recipe. The taste really isn't that bad ,little tangy, now that the carbonation has set but, the hops are WAY off on this.

[denny]

I would have given it 2 weeks in primary (at a minimum) in the low-mid 60s.  I always advise people to brew a recipe as it is before messing with it.  I made several test batches before publishing that recipe.  You can benefit from my mistakes of you make it like the recipe says.

[skyler]

sounds like old extract to me.

[gordonstrong]

sounds like old extract to me.

+1

Or it could be yeasty.