What is this?

[MatthiasS]

Hello,



what do you think this is?

Mathias

[MBrewer]

Hi Matt,

That looks like yeast to me, and I nice job of being able to isolate a signal colony. If you pulled that from a place that was not meant to have yeast I would say it is a wild yeast, other then that, it looks like you pulled a sample out of a fermenter.

Austin G.

[MatthiasS]

Hi,

so it is a sample out of a forced wort test. Usually when they are stable they have no signs of fermentation till day 8. The "dirty" ones start fermenting on day 6 (yeast, no bacteria). The plate is a lysine agar plate....so must be a wild yeast. I only recently started mibi step control in our brewery and if there is growth it's only wild yeast, no bacteria.
Our beers are usually clean except for a few times where we get a wild yeast infection (only with us05). Only had problems with this yeast. We sanitise the wort way with paa and our fvs as well. Afterwards we recirculate hot liquor for 10min through the wort way and hx and then into the fv where we let it drain, close all valves and wait for knock out. I don't understand why we would have a wild yeast in our unpitched wort.
The mentioned infection gets prominent on day three where a rubbery/phenolic flavour develops.

Any ideas/input?

Matthias

[scarne78]

Could have a biofilm somewhere. Pull samples from multiple points along the wort line and plate them. If you to have biofilm somewhere, that should help narrow it down.

[dick murton]

Check your CIP flow rate is adequate for the pipework size and chiller product duty. If you have at biofilm it is normally because of inadequate CIP flow rates, not lack of time, detergent or sterilant concentration or low temperature.

Don't drain the hot liquor out as this allows air, which might be infected to go into the pipe. When you run wort through the PHE, simply run the water to drain, and when you get wort, divert wort into the FV.

[Ted Briggs]

Buy some ATP swabs and go hunting.