Glass Hydrometer Test Tube - All Beverages. Test tubes are available in a multitude of lengths and widths to serve a varying number of needs. They are typically used by wine makers and home brewers to retain discrete samples of must or wort during testing and experiments. Test tubes are made from glass and or plastics. Plastics are formed using injection molding. Injection molding is a process in which plastic is heated and then injected, under pressure, into a test tube mold commonly made from metal. (A) 5395 Glass test tube 13 inch Glass 13 inch for all beverages. Removable plastic base. (B) 5390 Plastic 14 inch (wine or beer only) Plastic 14 inch for fermented beverages only. (C) 5396 Plastic 12 inch removable base (wine or beer only) Plastic 12 inch for fermented beverages only. Removable base for easier cleaning. (D) 5392 Plastic 14 inch (high alcohol / distilled beverages) Plastic 14 inch for ALL beverages including distilled items. One piece molded, alcohol resistant, dishwasher safe.