I also posted this message in rec.crafts.brewing and got a few
replies.
I seems it is a benign wild yeast causing the problem floating around
in my basement where I brew. this is my answer to them.

I racked a batch last sunday in the same sterilized carboy I had the
problem with, and wednesday the white skin was back on top.

I will be sterilising all my equipment for the next few days and hope
that will be the last I see of the white scum.
BTW even though it's only a week in the keg the beer doesn't seem to
taste bad. It can only get better with age

thanks again

PeterB


On Tue, 30 Jan 2007 18:47:12 -0500, "PeterB"
<PeterB2home.alone.drinking.homebrew> wrote:
[color=blue]
>2 weeks ago I racked 5 gallons and after 5 days a white skin appeared on the top.
>I asked the local brew store and was told it was caused by a benign yeast. It wouldn't affect the taste, but was near impossible to get rid of.
>I cleaned the carboy, racking cane and tube as well as I could BUT!!
>The last batch I racked on saturday has just developed the same white scum on top.
>Do I have to throw the carboy or does anyone know how I can stop the rot?
>
>Any answers greatfull received
>
>PeterB[/color]