Oxidation questions

[Gropo]

My last several brews have had (what I suspect to be) oxidation issues. the "off-flavor" is kind of sweet, with a harshness on the sides of my tongue....not a painful "lacto" type off flavor, but just not right. I brew AG IPA's almost exclusively, dry-hop in the primary, and purge my keg and auto siphon with co2 before transferring. Any suggestions? Thanks.

 

[Gropo]

btw....I never have, nor do I ever plan on eating "wet cardboard"...so that description of oxidation doesn't mean much to me.

 

[day_trippr]

From the description I'm thinking more fusels than oxidation. At what temperature do you run your yeast during primary fermentation?

Cheers!

 

[Yooper]

My last several brews have had (what I suspect to be) oxidation issues. the "off-flavor" is kind of sweet, with a harshness on the sides of my tongue....not a painful "lacto" type off flavor, but just not right. I brew AG IPA's almost exclusively, dry-hop in the primary, and purge my keg and auto siphon with co2 before transferring. Any suggestions? Thanks.

That does sound like oxidation to me. It's only "wet cardboard" when terribly severe. In early stages, it's exactly how you describe. Then it gets some "sherry" type of flavors, and then almost like brandy flavors. After that is when the cardboard comes. Most beers that I've tasted that have oxidation are generally not that severe, and I think I"ve only had "cardboard" in a couple of beers that I"ve sampled in all the years I've been drinking homebrew.

I'm not sure where the oxidation could be coming from, though. Are you fermenting in an ale pail for a week or two, then gently dryhopping?

 

[grathan]

Why not seperate out a gallon next time you ferment and oxidize it intentionally just to see?

What are you using for dry hops?

 

[Gropo]

Thanks for the replies. I use thick slurry, cultured 1056 from local brewery. Ferment in a 6.5 gallon glass carboy which I submerge in a tub of cool water.....usually ferment around 66 - 68, although sometimes while I'm at work during active fermentation it might jump up to 70-ish. I never rack to secondary; usually dry-hop with about 4oz of pellets dropped directly into primary. I give it a gentle "swirl" once a day during the dry hop period. Cold-crash after 7 days, purge sanitized keg and auto siphon with c02. Kinda stumped as to why/how my beers might be getting oxidized.

 

[grathan]

So nothing has really changed the last several brews to be a cause?
What about warmer weather? Perhaps the off flavor arrived with warmer temperatures.


What about the dry hops. Are you using fresh 4oz or is this some large bag you've been using for a while?

What about the co2 tank? How long since it was filled? Did you swap it out about the same time the off-flavor started appearing?

 

[Brewcycle69]

I've had some oxidation creeping in lately, the CO2 tank is an interesting thought because I did swap it out about the same time I started getting oxidation issues, but never considered it as an issue. What role would the tank play? OR Could the CO2 be bad??

 

[grathan]

I don't know. I swapped tanks recently and my beers seemed to take a flavor dive. I don't know if a compressor is used at some point in the process, but I imagine it so. If that compressor were to have leaks on the intake side it would be putting air into the tank, or perhaps a shop owner could cut the co2 with air to try to save money? This is wild speculation on my behalf.
It is possible to have co2 tested.
http://www.airbornelabs.com/html/isbtpuritychart.HTM

If your oxidation is appearing in IPA style beers mainly, I would look at your dry hopping instead.

 

[bethebrew]

I don't know. I swapped tanks recently and my beers seemed to take a flavor dive. I don't know if a compressor is used at some point in the process, but I imagine it so. If that compressor were to have leaks on the intake side it would be putting air into the tank, or perhaps a shop owner could cut the co2 with air to try to save money? This is wild speculation on my behalf.
It is possible to have co2 tested.
http://www.airbornelabs.com/html/isbtpuritychart.HTM

If your oxidation is appearing in IPA style beers mainly, I would look at your dry hopping instead.

Wait until it's illegal to buy CO2 because as everyone knows (cough cough) mankind is responsible for global warming, and needs to be taxed or punished using CO2 as a scapegoat.

OK political rant done. I've always wondered if CO2 from the store, or stored in aluminum tanks, contributes some of that nasty harshness I find in many other beers. Personally I bottle each one of my beers, and have accumulated a few thousand spare bottles to refill. Bottling is fun. I say that to myself a lot and it seems to work. Bottling is fun. See!

Then I ask myself, well maybe it was the pellet hops that are giving the beer that unpleasant bitter metallic twang that they don't seem to care about anymore, and not the CO2.

 

[bethebrew]

Thanks for the replies. I use thick slurry, cultured 1056 from local brewery. Ferment in a 6.5 gallon glass carboy which I submerge in a tub of cool water.....usually ferment around 66 - 68, although sometimes while I'm at work during active fermentation it might jump up to 70-ish. I never rack to secondary; usually dry-hop with about 4oz of pellets dropped directly into primary. I give it a gentle "swirl" once a day during the dry hop period. Cold-crash after 7 days, purge sanitized keg and auto siphon with c02. Kinda stumped as to why/how my beers might be getting oxidized.

Your "gentle swirl" surely is adding O2 each time.

Maybe try a pack of US-05 next time maybe your local brewery yeast is changing.

The other thing is 70 is too warm. That yeast loves 62-64 actual ferment temp so maybe a 60 deg fermentation unit.

And 4 oz of pellets dry hop in one carboy seems like an AWFUL lot. Hops get oxidized. How old are they? How are they stored?

 

[Brewcycle69]

I don't know. I swapped tanks recently and my beers seemed to take a flavor dive. I don't know if a compressor is used at some point in the process, but I imagine it so. If that compressor were to have leaks on the intake side it would be putting air into the tank, or perhaps a shop owner could cut the co2 with air to try to save money? This is wild speculation on my behalf.
It is possible to have co2 tested.
http://www.airbornelabs.com/html/isbtpuritychart.HTM

If your oxidation is appearing in IPA style beers mainly, I would look at your dry hopping instead.

Thanks, wild speculation is what I have left. Funny thing in my situation is I have the beer sitting on gas for two weeks, when I tap it the first couple of glasses are really good, then after a day a little "hot" taste starts to creep in. I just use party taps and beer line from the LHBS, the line is pretty thick so haven't thought of it as the problem.

 

[grathan]

Thanks to a new larger Speidel fermentor, I plan to start making larger batches, where 5 gallons will go to keg with force carb and leftovers 2 gallons will be natural bottle carb. While I don't expect any differences I would also like to assess hop flavor fading in keg vs bottle.

 

[FarmerTed]

Cold crashing could be the issue; are you pulling air back in during the cold crash?

You could try conditioning the beer in the kegs with corn sugar; it might clean up any oxidation, but it will probably take longer to be ready to drink than what you're used to.