Beer problem

A woman was sleeping in her bed when her husband, crashing through the front door at 3 am, woke her up. He staggered and tried to get up the stairs.
"What are you doing?" she shouted.
The husband replied, " I’m trying to get a gallon of beer up the stairs!"
"Leave it down there!" she bellowed.
"I cant," he replied, " I’ve drunk it."