"... Germans are trained to spot fires from at least 30 feet away, so long as the faint smell of bratwurst can also be detected. But their delight at the possibility of an afternoon wurst soon turns to horror when their nostrils cannot smell any complimentary sauerkraut. The implication is then clear: A house is on fire. Seems like an odd leap in logic, but they've never been wrong once, hence the phrase "If there's meat in the air but you can't sniff the kraut, a house is on fire, you best put it out..."