mcbethenstein
Well-Known Member
Wow,
There has been quite a bit of discussion on this while I was gone! Suffice it to say, perhaps the depth of the fermenter on a homebrew scale has less to do with the increased ester levels than the psuedo-open aspect of it. But it does make a difference and a tastable one at that. Even the non-super tasters at our learn to brew day could distinguish the highly ester-y characteristics of this beer. I am still inclined to believe that ratio of surface area to depth is a deciding factor (Although NOT the sole factor). With that level of surface area there is a freer exchange of Oxygen and CO2. Most brewing science out there suggests that increasing Oxygen will actually decrease ester production, which is opposite of what we are seeing here. However there is also info out there that suggests that increasing CO2 concentrations also "scrub your beer" clean. Off flavors and esters are picked up by the CO2 and then driven off after the CO2 is pushed out of the beer and through our blow off tube or airlock. With so much open space, CO2 off gases easily and with decreased concentration in the wort and decreased contact time may allow for more esters to remain in the finished beer. Here is a powerpoint from David Bryant at the Brewing Science Institute that summarizes the findings of many major studies by the german Hefe brewers. It is far less technical and more understandable to me than a number of other references I've come across lately, along with real world observations by the brewers themselves.
http://www.mbaa.com/districts/MidSo...2010-03-13Wheat_Beer_Yeast__Fermentation2.pdf
There has been quite a bit of discussion on this while I was gone! Suffice it to say, perhaps the depth of the fermenter on a homebrew scale has less to do with the increased ester levels than the psuedo-open aspect of it. But it does make a difference and a tastable one at that. Even the non-super tasters at our learn to brew day could distinguish the highly ester-y characteristics of this beer. I am still inclined to believe that ratio of surface area to depth is a deciding factor (Although NOT the sole factor). With that level of surface area there is a freer exchange of Oxygen and CO2. Most brewing science out there suggests that increasing Oxygen will actually decrease ester production, which is opposite of what we are seeing here. However there is also info out there that suggests that increasing CO2 concentrations also "scrub your beer" clean. Off flavors and esters are picked up by the CO2 and then driven off after the CO2 is pushed out of the beer and through our blow off tube or airlock. With so much open space, CO2 off gases easily and with decreased concentration in the wort and decreased contact time may allow for more esters to remain in the finished beer. Here is a powerpoint from David Bryant at the Brewing Science Institute that summarizes the findings of many major studies by the german Hefe brewers. It is far less technical and more understandable to me than a number of other references I've come across lately, along with real world observations by the brewers themselves.
http://www.mbaa.com/districts/MidSo...2010-03-13Wheat_Beer_Yeast__Fermentation2.pdf