Purging O2 from bride before transfer: DO meter needed?

[TimBrew Slice]

I am looking to measure the O2 level of gas coming out of the blowoff tube in my brite tank. Possibly push CO2 through the bottom until the gas coming out of the blowoff arm is at a sufficient level? I know the DO meters needed to measure packaged beer are very specialized and expensive, but does anyone have experience with a less expensive version that can just measure the amount of O2 in air? I'm not really trying to measure the beer itself, just the environment it's going into. We had an IPA get noticeably oxidized a couple of days after being transferred into the serving tank. I've researched many methods of purging the brite and will be trying them, but would like a way to measure their effectiveness.

Thanks!

EDIT: Brite not bride. doh.

[theomuller]

You’re looking for a headspace oxygen meter. They can cost as little as $4000 last I checked. you need one that measures in the ppm range; purging to ~100 ppm or less will get you very, very good (low) DO pickup.

[brewingpro]

oxygen purge from bright

A simple test to see if the gas coming out of the bright tank is close to pure CO2 is to simply bubble some into a caustic solution. The CO2 is neutralized, and any remaining bubbles are oxygen, nitrogen, etc.

Zahm & Nagel sell an apparatus to do this. It was handy in old breweries back before the day of buying liquid CO2. They would test the purity of the gas coming off of the fermenter, saving it for reuse once it tested out pure CO2.



Take a five gallon bucket with 2- 3 gallons of a 5-10% caustic mix. Then bubble some of the bright tank gas out through a hose into the bottom of it, just like it if it were a fermenter gas trap. Throttle it back to prevent splashing, etc.
Pure CO2 should have the bubbles disappear before reaching the surface. Less pure will have more bubbles make it to the surface.

A rough test, but fairly easy. Wear safety glasses,there will probably be some splashing!

You should even still be able to re-use the caustic to clean a tank.