I recently did a hands on review of a Milwaukee MW600 Dissolved Oxygen meter for HomeBrewFinds. Review linked here. As part of trying out the meter, I did a bunch of different experiments looking at dissolved oxygen. One of them that the results surprised me on was method of beer transfer from finished fermentation to the keg. I mostly am able to do closed transfers now, pushing the beer out of fermentor into keg using bottled CO2, and it seems like that was the best method to reduce oxygen into my finished/kegged beer.
On the fermentors that I can't do a closed pressure transfer, I use a diaphragm pump to transfer the beer. I had thought that with my method and the style of the diaphragm pump it would be pretty low oxygen, but I had no data other than my personal belief.
As a comparator to the above two methods, I did one transfer with a stainless steel siphon. I figured this would be the worst for oxygen pickup. Definitely I thought the open lid of the receiving keg, even though the keg had been CO2 purged, would pick up a lot of oxygen.
It was surprising that the results showed all 3 methods had pretty much the same measured DO in the beers after transfer.
On the fermentors that I can't do a closed pressure transfer, I use a diaphragm pump to transfer the beer. I had thought that with my method and the style of the diaphragm pump it would be pretty low oxygen, but I had no data other than my personal belief.
As a comparator to the above two methods, I did one transfer with a stainless steel siphon. I figured this would be the worst for oxygen pickup. Definitely I thought the open lid of the receiving keg, even though the keg had been CO2 purged, would pick up a lot of oxygen.
It was surprising that the results showed all 3 methods had pretty much the same measured DO in the beers after transfer.