Ask The Brewmasters

This message was posted by a user wishing to remain anonymous

I work in an older US brewpub that was built in an old factory building. The fermentation room has brick walls behind the BBTs. One BBT in particular has developed an aroma of cooked onions every time we CIP. We guess this is from heating up the tank and that it has some microflora on the exterior or on the wall behind it. Despite being in very close proximity to two other BBTs (i.e. less than six inches), neither of these BBTs has the same issue. We have scrubbed the tank on all exterior walls and the walls behind the tank. We have never had issues with microflora inside the tank and beers coming out of the BBT are clean. Any thoughts on how we might resolve the aroma issue?

Not sure what sort of microbes or decomposition may cause this aroma if you have wet insulation, but that vessel may have wet insulation.  Could come from a glycol leak or a jacket that is not fully welded and open to water from periodic exterior cleaning.  Without knowing anything about your brewery, it may be that there is a cracked weld that only opens up during hot CIP, allowing some beer/yeast leakage into the jacket and feeding some population of microbes.  If you don't distribute or package, you may never notice micro issues from this sort of failure.  If that is a possibility, check out the interior of the tank with a penetrant dye followed by visualization using a developer.

Would really have to putting the heat to a vessel to warm up the exterior, let alone a brick wall located 6 inches from the tank wall.

Cheers,

Ashton

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Ashton Lewis
Manager of Training and Technical Support
BSG Craftbrewing
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
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