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Author Topic: Eliminating oxidation flaw in kegged beer  (Read 3606 times)

S. cerevisiae

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Re: Eliminating oxidation flaw in kegged beer
« Reply #15 on: March 27, 2015, 04:09:19 pm »
I was recently upset to find out that an otherwise very good hoppy american session ale was starting to show signs of oxidation - short finish, cardboard taste.

The precursors that are responsible for cardboard staling are developed in the mash, not while racking from the fermentation vessel to the keg (google "lipoxygenase" and "trans-2-nonenal"). 

Offline stevecrawshaw

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Re: Eliminating oxidation flaw in kegged beer
« Reply #16 on: March 28, 2015, 02:30:32 am »
The precursors that are responsible for cardboard staling are developed in the mash, not while racking from the fermentation vessel to the keg (google "lipoxygenase" and "trans-2-nonenal").

Hmm. There seems to be quite a lot of debate about the source of this flaw. The most informative site my quick google turned up was here:
https://beersensoryscience.wordpress.com/2010/11/15/chemistry-of-beer-aging/
Which, as you say indicates that T2N is developed in the mash, advising that a low mash pH and high mash temp will reduce it.

I am pretty diligent with my transfer technique - transfer under CO2 blanket via out post in a twice purged corny keg, so it makes sense that T2N is coming from elsewhere.

Both that site and this one
http://www.flavoractiv.com/products/papery-beer-flavour-standard/

advise that adding sulphites will reduce staling so I think I will try that approach for my hoppy beers.
cheers
steve
I like to keep a bottle of stimulant handy in case I see a snake, which I also keep handy.

Offline Werks21

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Re: Eliminating oxidation flaw in kegged beer
« Reply #17 on: March 29, 2015, 12:27:43 pm »
I may need to try this yeast trick on some cider. I don't know that it is O2 for sure but its the only thing I can think of. The cider doesn't have a definitive cardboard or paper taste, its more like mildew and appears on the back end of the cider. The reason I think it is O2 related is because I racked to secondary to store it on the late side so I don't think the airlock was moving after the transfer, and I did not put Co2 in the carboy to blanket it. I just spaced out on the whole thing. Another lesson learned I guess. Does anyone have experience with Oxidation in cider? Is mildewy normal for this flaw?
Jonathan W.
Snohomish WA

Offline YooperBrew

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Re: Eliminating oxidation flaw in kegged beer
« Reply #18 on: March 29, 2015, 08:06:25 pm »
I may need to try this yeast trick on some cider. I don't know that it is O2 for sure but its the only thing I can think of. The cider doesn't have a definitive cardboard or paper taste, its more like mildew and appears on the back end of the cider. The reason I think it is O2 related is because I racked to secondary to store it on the late side so I don't think the airlock was moving after the transfer, and I did not put Co2 in the carboy to blanket it. I just spaced out on the whole thing. Another lesson learned I guess. Does anyone have experience with Oxidation in cider? Is mildewy normal for this flaw?

"Mildewy" generally isn't a description I would use for oxidation in cider.  I'd think first of "sherry" or even "brandy" type of flavors, or even "stale".  A good example would be if you ever left a wine sit overnight after opening, and tried it the next day.  That 'blah' almost flat flavor would be the first sign of oxidation.  Darkening of a cider is also a big sign.   Mildewy seems to connote a bacterial component.  I assume the cider wasn't topped up? 


Offline Werks21

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Re: Eliminating oxidation flaw in kegged beer
« Reply #19 on: March 30, 2015, 05:43:32 pm »
I believe the cider was darker too. I had two batches made in quick succession and one was significantly darker but it just chalked it up to whatever/ some unknown. My vocabulary and palette are a work in progress so I think Im gonna bring some to the local home brew store and have the owner taste it. He is a pretty helpful guy and the only person I know locally who would be able to ID the flavor for sure. Perhaps mildewy is a bad word. Maybe musty, or stale but I don't think sherry, paper or cardboard fit the bill. I may try leave a few ounces of wine or beter yet cider sit overnight to see what its like. thanks for the info. And no, the cider was not topped up or fortified with any other sugars. I did dose it with 9 Campden tabs and let is sit before starting
Jonathan W.
Snohomish WA