White substance around bung

[ZinKin]

The other day I went to our neutral oak barrel and there was this white substance accumulating around the bung hole. I scraped it off. Wtf is that about? Its aging and finished now.

 

[salcoco]

not kin owing the consistency of the white substance it could be anything from a bacteria film to tartaric acid. I usually sprayed a sulfur solution around the bung every time I checked the barrel.