Would a beer still be good after being cold then hot then cold again? My main question is really, I guess - how resilient is beer? I have some beer in my refrigerator that was cold when I bought it. I couldn't bring it home quickly due to having to visit my fiancee's grandmother in the hospital (short notice). It got pretty warm sitting out in the car and I have it refrigerated again. My roommate took one out to drink it, but fell asleep before he opened it - therefore, it got warm (room temperature) again. If I were to put it back in the refrigerator a third time, would the beer still be safe to drink? Would there be any quality loss?
There should be no reason why beer would lose any quality from being left out at room temperature then being re-cooled.
During the brewing and distribution process beer is exposed to a wide range of temperatures numerous times.
Some specialist beers may include &quot;adjuncts&quot; or additional ingredients (fruit, honey etc...) that may be affect quality with a temperature range (none spring to mind).  However normal beer made with malt, hops &amp; water should be fine.
Exposure to sunlight is more likely to affect beer than temperature.