Weck jar secured by steel tension clips which can be removed once a vacuum seal has formed. During storage the vertical position of the rubber seal's external tongue indicates the status of the sealing. Weck products are still produced and are available from German hardware and online stores. Used equipment is frequently sold on online auction sites and in opportunity shops. Weck jar A Weck jar is a molded glass jar used in canning to preserve food. It is popularly used for jam preservation, for its minimal look and foolproof rubber gasket with a glass lid. Weck jars were created by the
David S. Mason David S. Mason David Stewart Mason (born November 23, 1947) is Professor Emeritus of Political Science at Butler University in Indianapolis. His most recent book, "The End of the American Century" (Rowman & Littlefield, 2008) explores the interrelated dimensions of America's domestic and international decline. That book has been translated and published in China, by the Shanghai Lexicographical Publishing House. Mason was born in Washington, D.C. in 1947; received his B.A. in Government from Cornell University in 1969; his M.A. in International Affairs from the Johns Hopkins School of Advanced International Studies in 1971; and his Ph.D. in Political Science