Ok, maybe there is no great debate but what the hell. We've all heard and digested the explanation of nitrogen beer's tiny cascading bubbles and contribution to creamy mouthfeel.
I first leaned the "science" of nitrogen bubbles from Cecil Adam's Straight Dope column and have been repeating this notion (which I now believe to be flawed). To wit, according to the column:
"From my online reading I learned that the secret of Guinness's creamy mouthfeel, as the taste experts put it, is a mix of nitrogen and carbon dioxide rather than pure CO2 as the bubblizing ingredient. Nitrogen bubbles are much smaller than CO2 bubbles, a mere 50 microns in diameter, and produce a smoother head. But nitrogen doesn't produce bubbles as spontaneously as CO2. At the corner tap they deal with this by using a special nozzle that aerates the stout with nitrogen as it's poured."
But of course, what is ignored is why the hell is CO2 needed at all in this mix? And why aren't there mixed populations of little nitrogen bubbles and large CO2 bubbles?
Here's what I now believe. CO2 is needed because the foam consists of CO2 bubbles. The bubbles are small because of the manner in which they are formed (by jetting the beer through tiny apertures). The role of Nitrogen is to provide the driving force (in other words, 6 PSI of Co2 would do a piss poor job of driving beer through a stout faucet). I've tried carbonating with pure CO2 then connecting beer gas and the beer pour perfectly right away without time for the equilibration of nitrogen gas in solution?
Your thoughts?
Link to Cecil Adams' Guinness column:http://www.straightdope.com/columns/read/1368/why-do-the-bubbles-in-guinness-stout-float-down
I first leaned the "science" of nitrogen bubbles from Cecil Adam's Straight Dope column and have been repeating this notion (which I now believe to be flawed). To wit, according to the column:
"From my online reading I learned that the secret of Guinness's creamy mouthfeel, as the taste experts put it, is a mix of nitrogen and carbon dioxide rather than pure CO2 as the bubblizing ingredient. Nitrogen bubbles are much smaller than CO2 bubbles, a mere 50 microns in diameter, and produce a smoother head. But nitrogen doesn't produce bubbles as spontaneously as CO2. At the corner tap they deal with this by using a special nozzle that aerates the stout with nitrogen as it's poured."
But of course, what is ignored is why the hell is CO2 needed at all in this mix? And why aren't there mixed populations of little nitrogen bubbles and large CO2 bubbles?
Here's what I now believe. CO2 is needed because the foam consists of CO2 bubbles. The bubbles are small because of the manner in which they are formed (by jetting the beer through tiny apertures). The role of Nitrogen is to provide the driving force (in other words, 6 PSI of Co2 would do a piss poor job of driving beer through a stout faucet). I've tried carbonating with pure CO2 then connecting beer gas and the beer pour perfectly right away without time for the equilibration of nitrogen gas in solution?
Your thoughts?
Link to Cecil Adams' Guinness column:http://www.straightdope.com/columns/read/1368/why-do-the-bubbles-in-guinness-stout-float-down