We've been looking for some
information on 'best practices' for preparing brew pub conditioning and serving
tanks (7, 10, and 20 bbls) for receiving beer. This question is
motivated by our experience of premature spoilage of our Stout and
Brown ales (accelerated oxidation in melanoidin-rich environment?). I've been digging around on the BA Forum and in the MBAA Practical Handbook, but have not found anything specifically addressing how best to purge a tank with CO2.
I have had decent results over the years using the "sniff test" method of introducing CO2 through
the bottom of our conditioning and serving tanks and gauging when CO2 displaces
O2 by the 'sting' of the discharging gas in the nose. In spite of the subjective nature of that method, it has proven a decent, if unsafe, SOP. Now that we have three pubs staffed by three different brewers, the method is
Are there any resources you know of that address 1) efficacy of purging from the bottom w/ CO2 and transferring fully-attenuated beer immediately/on the same day vs. letting "purged" tank stand overnight under pressure before transferring; and 2) a device that can accurately, consistently, and reliably detect gaseous O2 levels as they exit a conditioning/serving tank (in our case through the CIP arm)? Questions have arisen about to what degree o2 and CO2 mingle when purging a tank and how that might impact the life
expectancy of our Brown and Stout. No doubt there are other avenues of inquiry
about why beers might spoil, but we're only currently experiencing this in
these two styles (and not right away upon serving = ~3 weeks after brewing).
FYI: similar methods are employed prior to moving/serving hop-centric pale ales, and we're not experiencing the same degree and/or rate of degradation.
Any insights you might be able to share would be much appreciated.
The best way to purge a tank is to fill it to overflowing with
water and then press the water out with CO2 or N2 gas. The water can be
pressed to another tank for other use or sent to the drain. This will
give you an anaerobic interior to the tank but the beer going in should be
through a packed line. Fill your beer hoses with water until you get all
the air bubbles out and then push the water out with beer before allowing it to
go into the tank that way you don’t re-contaminate the tank with air.