ocluke
Well-Known Member
Their underlying comment was "oxidation", and lack of flavor, and no malt backbone. This beer was bottled, and they tasted it right at the 3 week point after bottling. Didn't have an excessive aging time or anything like that. Up until now I have recirculated during the mash as I have a direct fire system. The probe in my pump gives me my mash temp, so I need to recirculate to get an accurate reading. Then my flame kicks on whenever directed by the temp controller (if the temp drops too low). I don't think I've seen one brewery (at any level) recirculate during the mash. I'm wondering if this might be pushing the limits of aeration on the 'hot side', and making aeration an actual possibility. Because the outlet of the pump is limited by a ball valve that is maybe a quarter open, the March pump is still running at full speed, introducing the wort constantly to air/oxygen. On top of that it's being pumped in the top of the mash tun, and splashed down on top of the grain bed. I just wonder how detrimental the pump running is as it is churning the wort the head due to running at full speed but only letting a low flow rate out of the pump. Any thoughts here? How else could I have gotten such high oxidation comments on a 3 week old beer?
I have the same setup as you describe and do not have issues with oxidation. That said, my wort is returned to the grain bed about 1/2" below the top of the liquid through a silicone tube (there is no splashing). Assuming you don't have any compromise in your pump system causing it to take in air, the impeller turning shouldn't affect the wort.
My guess is that it's something else in the process. It can happen at any temp above 120°F on the hot side, but is often from the cold side with homebrewers, in my experience (transferring to secondary, bottling, using a carboy cap instead of a bung, cold crashing and sucking in ambient air through the airlock, etc.)
On a side note, 2 of the 3 criticisms you mentioned from the judges are not necessarily (or even likely) related to oxygen.