mculley1375

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I'm a new member and one of the reasons I am a new member is that I would like to talk over how severe the effects of oxygen on fermenting wort really are. Charlie Papazian tells me that I want to minimize the exposure of fermenting wort to the air. Well... as with most things its a matter of scale. Namely, how much is too much?

-Mark

NWernBrewer

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Too much is how much you can taste in the final product and how well you want it to age.

I would say limiting air exposure to the best of your ability would be about enough.

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mculley1375

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The measurement of "Too Much" being when the taste is negatively changed is implied.

I have never done a side-by-side comparision of two beers, one with limited air exposure and one that had "Too Much" air exposure. So how do I calibrate my palette to differentiate between the two? I would guess that few of us can taste a beer and say, "Ah, that's really close but I think it was exposed to too much air".

Is air exposure binary? When it comes to air exposure has the fermenting wort either been exposed to "Too Much" and everything else is negligable?

BarleyWater

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This is how I think of it. Unless you are purging your head space with co2 though, you really can't completely get rid of air. So, any really is "too much", but it really is hard to avoid. The key is to be a diligent as possible when transfering, making sure there is no splashing or too much turbulation, and drinking before the effects really start to set in. Beers will slowly develop the wet carboard flavor associated with oxidation after O2 exposure, but it takes a while. If you start to taste anything off, drink the rest up quickly, but as a genaral rule, you will have a few months in the bottle, depending on the style, before any problems are really noticable.

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Funkenjaeger

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The only time my beer touches air post-ferment is when I take hydrometer samples (often only once per batch, sometimes a few more if things are slow), and when I rack to a keg (avoiding splashing of course). If your process involves SIGNIFICANTLY more air introduction than that, then I'd guess you would need to reevaluate what you're doing, but otherwise I would not worry about it. It's certainly possible to oxidize your beer if you're careless, but the majority of homebrewers have a pretty similar amount of air exposure in their standard processes and don't have any problems. With the number of BJCP-certified beer judges present in the homebrewing community, any significant oxidation that occurred with normal brewing practices would not go unnoticed.

If you want to train your palate, you can intentionally oxidize a bottle of beer and do a side-by-side comparison. There is info out there on intentionally oxidizing the beer to help you study to become a BJCP beer judge (as well as reproducing lots of other off-flavors), try googling it.