Corrosion of Metals by Musts and Wines

Abstract

Since the repeal of prohibition and subsequent revival of the wine industry, many different metals and alloys have been included in winery equipment used in contact with musts and wines. Relatively little information exists on the behavior of these metals when subjected to various conditions existing at different stages of wine making. Searle, La Que, and Dohrow (1934) conducted an extensive series of corrosion tests in an eastern winery. The grapes and methods used in the wine industry of eastern North America, however, are very different from those used in California, so their data cannot be applied to the California wine industry. In order to obtain corrosion data under California conditions, tests were conducted with 46 metals and alloys in three California wineries. EXPERIMENTAL PROCEDUREThe methods used were similar to those employed by Searle, La Que, and Dohrow. Tests were conducted in two wineries located at Lodi where large wineries predominate and one in the Livermore valley where the wineries are smaller and devoted to the production of dry wines. Crusher, sump, and fermenter tests were conducted in the Livermore winery and in one Lodi winery. All other tests were conducted in one or both of the Lodi wineries.The metals tested were similar to those commonly used or suggested for use in winery equipment. A n attempt was made to select metals representing as wide a range of properties as possible. In all instances test pieces were cut to a surface area of approximately four square inches, determined accurately for each piece by the use of micrometer calipers. Some of the stainless steels were cut and then welded together in order to determine the effect of welding on the resistance to corrosion. A list of metals used and their approximate compositions are given (Table 1).The test conditions were those actually existing iii the wineries. As the conditions in any particular operation usually varied during a given test period, an effort was made to obtain an accurate log of the changes during each period. This information was often difficult to Chemist, Pacific Brass Foundry of San Francisco. 439

Trace elements analysis of wine by proton-induced x-ray fluorescence spectrometry

“…Trace element analysis of wine has long been of interest and concern to enologists. The deleterious effects on color, aroma, and taste of several metals, including copper, iron, zinc, nickel, tin, and aluminum, have been reviewed by Mrak et al (1937), Mrak and Fessler (1938), Amerine (1958), Amerine et al (1972), and Eschnauer (1974).…”