Issue link: http://winesandvines.uberflip.com/i/279499
W i n e s & V i n e s A P R i L 2 0 1 4 49 VA number, the most difficult issue with the cash still is running the tests. It is a clumsy procedure that takes about 30 minutes per sample and requires the full attention of the technician. Since it is a glass still and there is a nichrome wire heating the water in the still, all it takes is a few minutes of inattention and the nichrome cracks the glass bowl and the still is ruined. I know, I've done it! While enzymatic tests are easier to set up and run, their difficulty lies in account- ing for ethyl acetate. I have found from experience that as long as ethyl acetate is not organoleptically present, its contribu- tion to the final VA concentration is less than 10%. This means that unless the wine is near or over the legal limit, it is not a serious contributor to the problem from a legal standpoint. If ethyl acetate is noticeably present, it can be a significant percentage of the total VA. This becomes an issue if the VA needs to be removed by reverse osmosis. Removing this volatile acid is more difficult than removing acetic acid and can significantly raise the cost of VA removal. Like the other enzymatic procedures, one can use any 340nm UV-capable spec- trometer to analyze for VA. However, you can see a thread here: Most all of the enzymatic tests can be more simply done on one type of instrument such as the Randox Monza or the Mettler-Toledo version (which I have also used). Phenolics and color in wine Phenolic compounds are the most inter- esting yet most complex compounds we deal with in winemaking. Their very com- plexity makes it almost impossible for the basic winery laboratory to know much more about these compounds than mea- suring the intensity of the wine's color and its hue. Anything more requires equipment that costs tens of thousands of dollars and/or a laboratory setup man- aged by an experienced lab person with advanced degrees. To run the intensity and hue test for wines, the sample is prepared by filtration to 0.45µ and then analyzed in a spectrom- eter at 420nm and 520nm. Adding the absorption units give intensity and the ratio of 420/520 gives the hue. It's simple to run, but the spectrometer costs about $2,500. Adding a lot of labware and a UV/VIS spectrometer will supply more information about your phenolic com- pounds, but it is probably better to send a sample to your commercial lab partner for this information. Dissolved oxygen One of the important steps in winemaking is control of the oxygen in wine. I have f r e n c h o a k d o m i n o s P a r c d ' a c t i v i t é s d e s B e r t r a n g e s - 5 8 4 0 0 L a C h a r i t é - s u r - L o i r e - F r a n c e T e l . + 3 3 3 8 6 6 9 4 3 7 9 | F A X + 3 3 3 8 6 6 9 6 7 4 7 | w w w . t o n n e l l e r i e - e r m i t a g e . c o m Caroline Hoogenboom Napa - Sonoma Cell. (707) 364-6334 caroline@ermitageusa.com Amy Lee Oregon - Washington Central coast of California Cell. (509) 995-2771 amy@ermitageusa.com Vincent Garry Sales Director Cell. (707) 225-2105 vincent@ermitageusa.com Office: Tel: (707) 224-2377 Fax: (707) 224-2390 1285 Foothill Blvd Cloverdale, CA 95425 Mettler-Toledo offers several versions of its EasyPlus titration equipment. W I N E M A K I N G