Hello,
we ordered a new pitch vermont ale and streaked it on our standard copper sulphate agar plates and saw growth on them (>50 cfu) some smaller, some bigger colonies but morphology all the same. The beer tastes fine and nothing unusual. Cells look like a normal brewing yeast under the microscope. We plated from the container the yeast was delivered in and from the tank which has been cleaned very thoroughly (rinse - caustic - rinse - pasteurised (30min 80C) - acid - sanitised)
It is not some weird Belgium strain that might be resistant to copper sulphate. Maybe the concentration of the copper sulphate is too low in the agar?
We have brewed with that strain before and always had clean plates.
This is very strange.
I hope someone can help out here.
Matthias
we ordered a new pitch vermont ale and streaked it on our standard copper sulphate agar plates and saw growth on them (>50 cfu) some smaller, some bigger colonies but morphology all the same. The beer tastes fine and nothing unusual. Cells look like a normal brewing yeast under the microscope. We plated from the container the yeast was delivered in and from the tank which has been cleaned very thoroughly (rinse - caustic - rinse - pasteurised (30min 80C) - acid - sanitised)
It is not some weird Belgium strain that might be resistant to copper sulphate. Maybe the concentration of the copper sulphate is too low in the agar?
We have brewed with that strain before and always had clean plates.
This is very strange.
I hope someone can help out here.
Matthias
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