Bubble caps go into the top of column stills to increase reflux and exposure to copper surfaces. This is a display at the Four Roses distillery of the inside of a bourbon column still. Read more about it here.
Camper English is a cocktails and spirits writer for publications including Saveur, Details.com, Whisky Advocate, PopSci.com, Drinks International, and many more. Learn about Camper and Alcademics, or read clips of his published work.