debeer1-4, Exercise 3: Developments that spread lager

Model answer:

Any three of: refrigeration (Carl von Linde's machine in the 1870s) made cold lager brewing possible all year and anywhere, without ice or caves; Pasteur's work on yeast showed that fermentation was done by living organisms, making brewing more controllable; Hansen's pure yeast cultures at Carlsberg gave each brewery a reliable strain; Pilsner (1842) with pale malt and clear glass created a style that appealed everywhere; railways, bottling and pasteurisation allowed beer to be shipped far from the brewery; emigrant German brewers took lager brewing to the United States and elsewhere.