Wouldn't touch the Y class wine it burns through your oesophagus. I'd say with the majority of airlines I've been on the white wine and beer down the back is invariably on the warm side. Earlier on before the dry ice evaporates it's better but the further into the flight the warmer. Most refrigeration space is taken up by meal trollies. As crew used to put as many on ice as i could for those all night drinkers aboard.