Description Zahm & Nagel's products not only help make beer, but they help to measure the beer's "bubbliness", as well. The company manufactures carbonating and testing instruments used primarily in the beverage and brewing industries in more than 90 countries. Zahm & Nagel's testing products are used to measure air and carbon dioxide in cans, bottles, and brewing tanks, and the carbon dioxide purity of gas sources. The company also manufactures carbonating stones and other equipment used to produce carbonated beer. Zahm & Nagel sells its product to major breweries and bottling plants as well as to microbreweries.