Off Flavor From Taps

[brewdogdoug]

Hi all,

I’m experiencing an off flavor from my first pours out of our draft system, even when the beer isn’t poured for only a couple hours.

It looks like oxidation, it’s a cardboard type flavor that disappears after 10 or so ounces is poured then the beer tastes fine. And it happens on EVERY tap.

I’ve poured a beer and left it to warm and this flavor does not manifest at that point.

Our system has been thoroughly cleaned from our draft guy and it’s still occuring. I’ve also sprayed leak detector in all the fittings with no luck.

Please help me to stop dumping beer!

[brewdogdoug]

I should add this is the exact issue from this thread, but Brew Chef is no longer active on here unfortunately.

https://discussions.probrewer.com/fo...-an-off-flavor

[dick murton]

I suspect the seals are not food grade. Strip a couple of faucets and remove any joint seals from all you strip down. pour some beer and discard until you are sure it is off flavour free. Put all your seals into a screwtop brown glass bottle (don't want sunstruck flavours confusing the issue). Purge with CO2 / nitrogen and then fill brim with good beer. Leave for a few hours at room temperature, pour and taste. If this has the same taste, then the suppliers haven't been using suitable food grade rubbers.

I would be very surprised if either bugs or air ingress would produce noticeable cardboard flavours in just a couple of hours, but I know unsuitable valve seals or hoses can produce off flavours

[brewdogdoug]

I suspect the seals are not food grade. Strip a couple of faucets and remove any joint seals from all you strip down. pour some beer and discard until you are sure it is off flavour free. Put all your seals into a screwtop brown glass bottle (don't want sunstruck flavours confusing the issue). Purge with CO2 / nitrogen and then fill brim with good beer. Leave for a few hours at room temperature, pour and taste. If this has the same taste, then the suppliers haven't been using suitable food grade rubbers.

I would be very surprised if either bugs or air ingress would produce noticeable cardboard flavours in just a couple of hours, but I know unsuitable valve seals or hoses can produce off flavours

Thanks Dick! Really good points, sounds like a Monday morning science experiment.

[gitchegumee]

What is your beer line made from? Plastic in general is permeable by oxygen. That said, it would be hard to oxidize beer in only a few hours, so maybe something else.