title_body: What would cause the same beer to taste different
upvoted_answer: There are several things going on here.  
  
  1) Temperature absolutely plays a difference in beer taste. 
  
  Too Cold
  
  
    The biggest issue with beer served too cold is the way the temperature masks many flavors and aromas. The cold temperature slows the volatilization of aromatic compounds causing them to linger in the beer. When these compounds are not released, it dramatically changes the apparent flavor and aroma of the beer, sometimes to the point where it may come across as thin and tasteless. (American Homebrewers Association).
  
  
  Too Hot
  
  
    Warm beer, on the other hand, does allow for more of the flavors and aromas to come to the forefront, but as beer approaches room temperature the sensations from hop bitterness and carbonation can decrease, which can lead to an almost flat-tasting experience. (American Homebrewers Association).
  
  
  So here are suggested temperatures for serving various types of beer. 
  
  ....................Beer ................................. Suggested  Temperature
  
  American Mainstream Light Lagers...............     33° – 40° F / 1° – 5° C
  
  Pale Lagers, Pilsners ...................................   38° – 45° F /  3° – 8° C
  
  Cream &amp; Blonde Ales     ...................................40° – 45° F / 5° – 8° C
  
  Nitro Stouts    ...................................................40° – 45° F / 5° – 8° C
  
  Belgian Pale Ales, Abbey Tripels    ..................40° – 45° F / 5° – 8° C
  
  Wheat Beers     ................................................40° – 50° F / 5° – 10° C
  
  Lambics     .......................................................40° – 50° F / 5° – 10° C
  
  Dark Lagers     .................................................45° – 50° F / 7° – 10° C
  
  American Pale Ales &amp; IPAs   .........................45° – 50° F / 7° – 10° C
  
  Stouts, Porters     ............................................45° – 55° F / 7° – 13° C
  
  Strong Lagers   .............................................50° – 55° F / 10° – 13° C
  
  Real &amp; Cask Ales ...................................... 50° – 55° F / 10° – 13° C
  
  Belgian Dubbels     .........................................50° – 55° F / 10° – 13° C
  
  
  Data from Tasting Beer by Randy Mosher.
  
  2) Glassware makes a HUGE difference. The shape allows for nucleation sites, temperature control of beer, aromatic release/retention. (See /user/MDMA's full response to my question about glassware and beer here)
  
  3) What type of beer is it? If it is a nano brewery, it could be several things (wild yeast, inconsistency in brewing process, fermentation time, bourbon barrels stored in, etc.).
  
  4) What was your drinking environment the first time/subsequent times you drank? Have you ever eaten somewhere for the first time while starving and with good friends you haven't seen in a while? That food will forever be amazing in your mind. You go back years later with a normal appetite and people you see regularly and the experience can be very different.