Franconian Beer Message Board
Mahrs U carbonation |
| Posted by Gerhard Schoolmann on 2015-05-01 02:14:23 |
| The gas is for pressing the beer from the KEG to the tap. In the Café Abseits the KEGs are in the cellar under the bar. So You need a pressure to overcome the height difference. In other places You find a long distance between the KEGs and the taps maybe also in the horizontal. Then You need more pressure. This gas has nothing to do with the gas in the beer. Optimally, the brewery delivers the KEGs with a precisely maintained pressure in the KEG ("Sättigungsdruck"; saturation pressure). Then the pub added their specific pressure to overcome the height and/or vertical difference between the place of the KEGs and their bar ("Förderdruck", feed pressure). As an optimal result the gas content of the beer itself doesn't change. In practice: - the delivered pressure in the KEGs can change because the brewery makes a fault - the knowledge of the pub waiter/owner isn't good enough and they work with a false pressure. - the pub changes their beers often and the breweries deliver KEGs without the information about their used pressure in the KEG. If the pub uses a too high pressure, a part of the gas goes into the beer. If the pressure is to low, the beer loses pressure and it's difficult to tap (too much foam) and the beer tastes stale. If You use pure carbonic acid. a part of the gas can go into the beer over time. This process is slower if You use a mix of carbonic acid and N2. My experience is that You can tap a KEG until 5 days with Aligal (a brand fo Air Liquid with a mix of 70% N2 and 30% CO2). I believe that Stephan has meant Aligal. It isn't available with pure N2 for drinks (only for filling food in packages, p.e. meat, cheese etc.) N2 is more expensive than C02.. |
| Followups: |
 Mahrs U carbonation by Uncle Jimbo on 2015-05-01 17:44:42 |