Issue link: https://read.dmtmag.com/i/40615
WINERY WINE TECH Alcohol Testing his method of testing alcohol level in wines has been around for decades and is still widely used by small and large wineries alike. Based on the boiling point of water calibrated against atmo- spheric pressure, this test is an excellent tool for most dry wines, and has an alcohol strength-by-vol- ume accuracy of 0.1%. If you are attempting to test alcohol in wines with residual sugar, be sure to understand that this test has its limits. Testing units are available for measuring alco- hol in wines with residual sugar, although they can be expensive. TOM PAYETTE Via Ebulliometer Step-by-step procedures for best results TOOLS AND EQUIPMENT Here's what you'll need for the test: Ebulliometer complete kit (I pre- fer Dujardin-Salleron, shown in the photo at bottom left) Distilled water Ethanol for burner lamp (Ever- clear or equivalent) Matches or lighter to light wick Dry wines to test Lab sink or a heat-proof container for dumping tested samples Ice-cold water for condenser Protective eyewear Material Safety Data Sheets (MSDS) and other protective gear for handling the unit and reagents. WHEN TO TEST Most winemakers conduct their The ebulliometer is a tried-and-true device used by many wineries for alco- hol testing. Photo: Tom Payette, www. winemakingconsultant.mobi WWW.VWM-ONLINE.COM alcohol analysis just after fermen- tation, to validate the success of their calculated predictions, and again after blending – within approximately three months before bottling – to confirm that their label printing will be in compliance with all regulatory agencies, such as the Alcohol and Tobacco Tax and Trade Bureau (TTB). Obviously, test- ing at any time is recommended if you suspect alcohol levels have changed. Tom Payette consults with established wineries to improve their products and sys- tems and assists in new winery startups. SHORT COURSE Calibrate using distilled water; be aware of atmospheric changes. Make sure the condenser cool- ing water is refreshed every five tests. Be gentle with the circular slide rule and thermometer. Run tests after alcoholic fermen- tation and three months before bottling. Spot-check your results with another trusted outside laboratory. CALIBRATION After you have set up the ebul- liometer unit, you must calibrate it using distilled water. Once you have determined the boiling point of distilled water, you can start the process of measuring the alcohol of a wine. When you hear a steady rumble inside the ebulliometer unit, take note of the mercury's rise. Photo: Tom Payette, www.winemakingconsultant.mobi SEPT - OCT 2011 VINEYARD & WINERY MANAGEMENT 33