Ask The Brewmasters

Dear Fellow Brewers,
We're considering Undercover Gassing with nitrogen as a substitute for CO2.
As a preliminary test, we purchased a bottle of nitrogen gas at 250 ppm oxygen.
Unfortunately, when we bubbled this gas through a 0.2 micron filter, we trapped a noticeable amount of a white, waxy substance which could be dissolved in dish soap but not caustic soda.
Does anyone know what this material might be?
Should we expect a similar outcome from a nitrogen generator?
Thanks in advance for your kind consideration.
Regards,
Daniel Carey
New Glarus Brewing Company

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Daniel Carey
Brewmaster
New Glarus Brewing Company
New Glarus WI
(608) 527-5850
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Dan,

I'm not sure what the waxy substance is, but for any nitrogen gas coming in contact with finished product I've always used UHP nitrogen.  Spec for UHP is <0.5 ppm oxygen, <1 ppm carbon dioxide/monoxide, and <3 ppm water.  I'm betting if you use a higher purity nitrogen, this will get cleaned up.  Hope this helps.

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John West
Director of Drink Manufacturing and Supply Chain
Louisville KY
(830) 998-1087
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HI Daniel.  I do not have an answer for the exact substance that your filtration is catching.  If your cylinder provider has a lab, I would ask them for an analysis.  If not, you could have any ISBT analytical lab perform the analysis.  In regards to nitrogen generators, we are capable of 99, 99.9 or 99.999 purity with 10ppm moisture and 0.1 micron filtration standard.

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Dick Mich
Adairsville GA
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Thanks John, Dick and Gerald for your kind responses.

In response to Gerald's questions - The gas used was was much greater than 99% pure. For the purpose of a bench top test, it was not certified Food Grade but was filled into a cylinder from a Food Grade source and blended to achieve 250 ppm oxygen. It was called "calibration grade" by our supplier. For the test, we sparged the gas through RO water for 30 seconds. Your hunch is most likely correct as we had no oil pick up when testing ultrapure gas. Plus we were able to prevent transfer of this waxy substance from the 250 ppm oxygen grade by passing it through a prefilter, carbon filter then 0.2 micro filter.

Regards,
Dan Carey

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Daniel Carey
Brewmaster
New Glarus Brewing Company
New Glarus WI
(608) 527-5850
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Original Message:
Sent: 08-12-2021 17:38
From: Gerald Alvey
Subject: Waxy Substance in N2 Gas?

I'm not sure I have an answer for you, but if you could answer the questions below, I may be able to get an answer for you.

Is the Nitrogen Food Grade 99% pure?

What do you mean bubble the gas? Was the gas injected into a liquid?