Linde's 1876 ammonia chiller made artificial cold an industry

Bottom-fermented beer — pils, lager and helles — needs temperatures below 9°C, and before mechanical refrigeration that meant brewing only in winter or relying on expensive natural ice cut from frozen lakes. Bavaria even banned summer brewing until 1865.

Carl von Linde, a Munich professor, spent six years developing a compression refrigerating machine. His first version used methyl ether, but leaking gas caused an explosion in the engine room. In 1876 he built a sealed ammonia compressor with glycerin seals that was safe, cheap and easy to maintain.

Installed at the Dreher brewery in Trieste in January 1877, the machine held fermentation below 9°C all year, so lager could be brewed in summer and exported worldwide. It ran until 1908, and ammonia compression became the standard for industrial refrigeration and later cold-storage logistics.