Persistant, subtle infection?

Doesnt really sound like an infection to me.
Sulfer smell is a normal by-product of fermentation which is more prevalent in some strains over others.

What yeast strains are you using?
What do your recipes look like?
Are you pitching enough yeast? Is it healthy?
Can you describe the "off flavor" in more detail?
Are you brewing all-grain? or is any extract added to any batches?

 

I agree with OddNotion.

I will also add that you should just start using StarSan as your sanitizer. I honestly can't think of a reason why anyone would need to use anything other than StarSan.

 

Had a brett infection that I eventually used bleach to cure.

 

Well, I meant that more in a "before you get an infection" sense.

 

I wasn't sure. But even then that was with fanatical sanitation practices on my part. I usually use pbw to clean, star san for sanitizing and anytime I use bugs I use bleach on all of it.

 

A lot of different sanitizers will work...bleach, Idophor, Trichloromelamine, Starsan....yada, yada, yada...for anyone kegging though, Starsan is the way to go, IMHO.

 

You will not regret switching to Starsan.

As for your apparent attenuation, the most likely cause is inaccurate measurements. This does not mean you've done something wrong, but most measurement equipment has a broad degree of accuracy. This of course isn't a definitive answer, but the probability is high.

 

The more times you reuse yeast, the more chance of a detectable infection. That is, you are picking up bioburden (wild yeast and bacteria) from the environment during every manipulation. Eventually you will get enough to detect off flavors in your beer.

However, still not sure this is an infection. Clarify what the flavor is you are detecting, folks on the forum should be able to chime in to help determine if this is what it is.

You will also need to describe the types of grain bills and yeast strains you are using to get your 80-82% attenuation. You are right - it does sound high - but need to check this to ensure it is indeed something out of the ordinary.

 

This is info I was hoping to get. If he is using WLP001/Wyeast1056 and has low to no crystal malt then 80% is not out of the realm of possibility at all... @JohnSnowNW brings up a good point about accuracy of measurements too though.

 

I think I had the same thing going on with my recycled yeast. It usually wasn’t enough to take hold in my main batch, but my parti-gyle would show more of the flavor defects.
Since then, I’ve learned to make a larger starter with the original vial/smack pack and save a portion of that pure yeast for my bank. It saves the worry because it keeps out more of the excess funk. No further problems.
Like the others have said, the sulfur from your primary is normal. My kids call it beer toots.

 

“Sometimes in some batches I get a little alcohol heat, even if its 6% abv.” That sounds like higher alcohols (fusel oils) to me. If the fermentation temperature gets a bit too high for a given strain of yeast, excess (perceptible) amounts of higher alcohols can be produced. The common descriptors for excess fusel oils are: harshness, hot.

Some people get hangovers if their homebrewed beers have too much higher alcohols.

Cheers!

 

68 in the swamp cooler or 68 at the actual wort temp during fermentation? Your wort will likely be 5-8 degrees over ambient temp during peak fermentation.

What temp are you pitching the yeast at?

Some of what you are describing sounds like it may be discussed in this article: http://byo.com/recipes-tag/item/182-beat-yeast-bite

 

If all you can describe it as is as 'yeasty', then perhaps it's something with your bottling/pouring practices? I used to just pour the whole bottle, dregs and all, cause I didn't think it mattered or that I cared. Well, then I tried pouring more carefully - there was a definite difference.

Maybe you're drinking a lot of yeast?

 

As was mentioned by @OddNotion, the critical temperature is the actual temperature of the fermenting wort (not the ambient temperature). What is the temperature of your fermenting wort?

Cheers!