Hi
Despite my heroic efforts to reduce exposure to air when transferring hoppy beers from FV to keg (and keg to keg), 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. This was in a keg. I read up on this problem, which I observe in hoppy beers more than other styles. In the Beersmith podcast with charlie bamforth on beer stability CB states that you can get rid of this flaw with yeast. So i decided to put it to the test. I made a small starter using mauribrew dried yeast and pitched into the keg when it was at high krauesen. Have left it for a week or so now. I tasted it last night and the oxidation flavour (trans 2 nonal I believe) has gone!
There is however a hint of diacetyl, which I hope will disappear with time. It is certainly nicer than the “untreated” beer and has gone from being a tipper into a drinker.
In the podcast CB also talks about using sodium metabisulphite as a precautionary measure to improve stability and reduce oxidation. I think I will try this for a subsequent hoppy style as I am quite sensitive to oxidised flavour in hoppy beers and I don’t like tipping beer. Not too worried about rheinheitsgebot…
Anyway, if you encounter this issue, adding yeast in the keg appears to resolve it, so worth a go…
From something I picked up on the old HBD back in the late 90s early 2000s timeframe, as to mix a campden tablet into the mash. The SO2 is an antioxidant that inhibits the oxidation of the malt compounds that lead to stalling. Any remaining SO2 is driven off in the boil.
I haven’t factored Campden tablets into the chemical mix, since I use RO, but how would one account for a tablet in the mash under the Brunwater spreadsheet. I am sensitive to water being chemically balanced and fear any changes, unless they are justified. Longer storage life is not an issue with my friends.
I experimented with this for over a year. I finally stopped when I saw no difference. To me, that meant that either it didn’t work or I didn’t have the problem to solve in the first place.
Yeah, definitely no trouble to use it. I just didn’t see the point after I tried it. I also do the elephant dance by spinning around 3 times before I brew. No trouble to do and I haven’t seen a single elephant around here!
Someday it might be good to do 2 batches of Pilsner, one with, one without, and see if there are any long term differences. But the Pils usually goes fast in this house.
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.
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?
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
