Poul Anderson 
Makeshift Rocket 

Knud Axel Syrup, chief engineer of the spaceship Mercury Girl, sat and drank his favourite beer and thought about the coming war he was so anxious to avoid. For Grendel — the planetoid on which he was stranded — had been occupied by a band of fiery Irish revolutionaries. And once the rival Anglians discovered this, there response would be speedy and violent.Then, as Herr Syrup shook up a bottle of brew and let the foam shoot out of its top, he realised suddenly what could be done to get him off Grendel.And so came about a marvellous spaceship — built of beer kegs, bound by gunk, upholstered with pretzel boxes, and powered by the mighty reaction forces of malted brew!