XPost: alt.home.repair   
   From: frede@mouse-potato.com   
      
   gtr  writes:   
      
   >   
   > Thank you for your keg experience, which is what I do not have.   
   > Why is a keg carbonated anyway? Isn't the beer already carbonated?   
   >   
      
   When you brew beer or other beverages, you normally do it in something   
   other than a keg. It's easiest if you have something with a wide top and   
   lid. That way, after fermentation is done and you transfer the liquid to   
   something else, it's easy to clean out the residue from the yeast,   
   etc. There's generally an airlock or "bubbler" in the lid of the   
   fermentation vessel to let out the extra CO2. That means that, while the   
   beer will be slightly carbonated after fermentation, it's not nearly   
   enough to be what most people these  days would consider to be   
   "carbonated."   
      
      
   You can then carbonate the beverage naturally or artificially (with   
   compressed CO2).   
      
   If you bottle the beer, if it has a bit of sugar and the yeast still   
   left, it will keep fermenting in the sealed bottle and produce   
   carbonation. Of course, this does produce some yeast residue in the   
   bottle (lees). It can also be dangerous if you misjudge how much   
   fermentation was left to happen. I'm told that exploding bottles of beer   
   are not at all fun. (This process of carbonation in the bottle is often   
   called bottle-conditioned.)   
      
   Some beverages are filtered after fermentation, and the filters are fine   
   enough that they filter out the yeast. (The typical US light pilsner   
   like Bud or Busch are filtered this way. The Adolph Coors Co. made   
   ceramic filters for use in filtering things like this - I'm not sure if   
   Coors Ceramic is still around or not...) These ceramic filters are not   
   typically something you'd use at home. The beer needs to be forced   
   through them under pressure and it still takes a while.   
      
   Without that yeast, you do need to artificially carbonate the   
   beverage. That could be done in large tanks or in the kegs. Tap systems   
   usually add some carbonation as well.   
      
   Let's say you've got Cornelius kegs and let the beer naturally carbonate   
   in them. Now you have a mess at the bottom and will have to clean it   
   once the keg is emptied. These kegs have kind of small "hatches" at the   
   top (or at least they used to - it's been a long time since I did any   
   brewing myself) and you need long-handled brushes to scrub the bottom of   
   the keg.   
      
   What you might do instead is keep fermenting in your tub or vat until   
   the sugar content is way down. Then you try to keep the residues from   
   being transferred over to the kegs, or maybe even use some filtering to   
   keep out the larger bits. Now you've got your beer in the keg and it's   
   not going to ferment much more and produce carbonation, so you need to   
   artificially carbonate it.   
      
   BTW, when bottle-conditioning beer, it's sometimes necessary to add a   
   bit of sugar when bottling if the beer didn't have enough left to ensure   
   good carbonation. Add too much and you have beer on the ceiling.   
      
   Beers and ales before modern times, with sealed bottles and kegs that   
   can withstand pressure and with tap systems, were typically rather flat   
   and might be unappetizing to people now.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)