I brew away from home, and last weekend I has to rush away before I was completely racking from primary to secondary. I can only go back in about 10 days. As a result, my beer is now sitting in a bucket with the lid on but with no airlock (exposed to open air through the airlock's hole). It's a pale blond ale with pitched with S-04 yeast about 3 weeks ago. Besides contamination risk, what do I risk ? Oxidation ? Anything else ? Thanks in advance, Arthur
Your biggest problem is probably bugs; fruit flies, flies, cockroaches, etc. If possible, get someone to cover the beer and protect it from critters. Cling wrap and an elastic should be enough.
Yes, there is a chance that your beer may have become infected (especially if bugs got in). But I would taste before kegging/bottling. If it tastes fine you are possibly safe. However, consume quickly in case the infection is young.
Oxidation should not be a problem as the yeast will consume the oxygen and the CO2 will form a layer on the beer to protect it from oxygen.
My experience with this is limited. I think Palmer talks about this in "How to Brew" (a must-have, IMHO). Anyhow; aside from wild yeasts, bacteria and fungi (oh my!) getting into your fermentor, air contact can also affect the flavor of the brew.