I had a look through the forums but couldn't find any information on this particular topic and thought I'd share. In case anyone else has run into this or does in the future.
I ferment in a converted fridge and typically use a blow off tub for the entire primary fermentation. I use starsan in my blow off bottle. I’ve noticed that with some fermentations that I get a black ring that forms on the blow off hose and even on the neck of the clear glass bottle I use. This happens without any Krausen coming out of the blow off tube.
In the latest case I actually changed out the blow off tube and bottle after the height of fermentation where Krausen was coming out of the fermenter.
My primary concern was that this is some sort of biological infection that could put my beer at risk. Took some samples of the black ring and took a look under 400X magnification.
Few other points:
• This stuff by the way is very difficult to wash off even when soaking in PBW.
• The starsan was perfectly clear and was made up recently with RO water.
• There is some discoloration of the starsan solution, goes lightly brown, but still mostly clear
• Tested the pH of the starsan and it was still ~2.5
• This beer is a dunkelwizen being fermented with Wyeast 3068 which does produce some sulfur
• Had this happen before and does seem to impact beer
So it appears to me that this stuff is residual mineral deposit caused when the C02 and other gases from fermentation bubble through the star san (pH of ~2.5). C02 + phosphoric acid -> ?. Or Something sulfur compound related?
My question is has anyone else run into this before? Any other opinions on what this is specifically and is it of any concern?
Here are some pics:
Ferment chamber and blow off set up
Here's the "black ring"
Here is the "gunk" at 400X. In my limited experience this looks mineral and not organic.
I ferment in a converted fridge and typically use a blow off tub for the entire primary fermentation. I use starsan in my blow off bottle. I’ve noticed that with some fermentations that I get a black ring that forms on the blow off hose and even on the neck of the clear glass bottle I use. This happens without any Krausen coming out of the blow off tube.
In the latest case I actually changed out the blow off tube and bottle after the height of fermentation where Krausen was coming out of the fermenter.
My primary concern was that this is some sort of biological infection that could put my beer at risk. Took some samples of the black ring and took a look under 400X magnification.
Few other points:
• This stuff by the way is very difficult to wash off even when soaking in PBW.
• The starsan was perfectly clear and was made up recently with RO water.
• There is some discoloration of the starsan solution, goes lightly brown, but still mostly clear
• Tested the pH of the starsan and it was still ~2.5
• This beer is a dunkelwizen being fermented with Wyeast 3068 which does produce some sulfur
• Had this happen before and does seem to impact beer
So it appears to me that this stuff is residual mineral deposit caused when the C02 and other gases from fermentation bubble through the star san (pH of ~2.5). C02 + phosphoric acid -> ?. Or Something sulfur compound related?
My question is has anyone else run into this before? Any other opinions on what this is specifically and is it of any concern?
Here are some pics:
Ferment chamber and blow off set up
Here's the "black ring"
Here is the "gunk" at 400X. In my limited experience this looks mineral and not organic.