Baudelot Cooler. Jean Louis Baudelot (1797–1881), was born in France, and studied engineering in Belgium. Though he claimed several inventions, fame came in 1856, when he patented a liquid cooler, specifically intended for the brewing industry. A cousin who was a brewer presented him with the fact that until then beer worts had to be cooled in a shallow vessel (cool ship) and stirred during a whole night—a process that easily took 8 hours. See coolship. Worse, the continuous exposure of the worts to the air resulted often in unwanted inoculation and infected beer. Yet exposure was mandatory because beer yeasts need oxygen at the outset of fermentation. Therefore, the wort needs to be well aerated. Baudelot envisaged a fine double copper sheet overlaying copper tubes (first cylindrical, later elliptical in cross-section) wherein cold water (spring water or icewater) ran countercurrent to the worts. The worts were collected on top of the cooler in shallow tray, and then finely dispersed, flowing over outside of the copper sheets, which were being being cooled internally. In this way, cooling took place in less than a quarter of the original time needed, limiting exposure to contaminating microbes, while aeration was assured. Hot wort flowed like an undulating waterfall down the exterior of the cooler, emerging cool and aerated at the bottom. It was a massive improvement that led to beer of much better quality and stability.

Baudelot opened a brewery (later taken over by his son) after patenting his invention, which was nonetheless shamelessly copied. The brewery served for experimenting and bettering his designs. Others also worked on his patent, not least in the US, where a new type was patented as late as 1939.

Though plate heat exchangers and shell-and-tube coolers have taken over, Baudelot coolers are still with us. In industrial/chemical plants, ultrafast cooling is still done by contemporary Baudelots, and in Germany, at least one commercial brewery still uses a stainless steel Baudelot today.