The 2015 growing season for wine grapes was particularly challenging in California. Enduring the grip of a vicious four-year drought (link to CNBC article), water allotments were a fraction of normal at an average of 20%. Hardy grapevines managed to flourish, and although yields were lower, flavors are expected to be better. As a result of the shorter growing season and warmer weather, the grapes ripened sooner. This affected the sugar content and resulted in a heavier, fruit-forward flavor and wine with higher alcohol content (link to wine analysis resources page).
Napa Valley Vintners
Most vintners in the Napa Valley region (link to Wine Industry Advisor) will remember 2015 as the year with the earliest harvest, which actually began on July 22nd with the picking of grapes for sparkling wine. After a dry, warm winter and a cool spring, grape clusters were small, with highly concentrated, rich flavors. Quality is running high but quantities are understandably low.
Analysis Solutions for Winemakers
Grape juice is composed of 70 to 80% water, 20% carbohydrates, and 1% organic acids, phenolics, vitamins, minerals, and nitrogenous compounds. Sugars, organic acids, and phenolics provide flavor, while the vitamins, minerals, and nitrogenous compounds are essential participants in the successful growth of yeast and the process of fermentation (link to Food & Beverage community page). The ability to measure and manage levels of sugar in juice or wine ensures a good final product. In wine production, the amount of fructose or glucose is an indicator of quality, and the content of D-glucose and D-fructose (total sugar) represents the amount of sugar available for fermentation by yeast. Too little glucose and fermentation will not happen properly.
Acids are an important component in wine, as they contribute to its crisp, tart flavor. Alcohol, sugars, minerals, and other components balance the sourness of the acids (tartaric, malic, and citric acids). These acids are naturally present in grapes and provide the freshest, purest tastes. Lactic, acetic, and other acids also play a minor role in fermentation and contribute milder, more complex flavors. Some acid is desired by yeast during fermentation, but more importantly, the final level of acids will contribute to the flavor complexity of wine and stop the growth of potentially harmful microorganisms that may spoil the end product. Monitoring acid levels during various production stages improves productivity and ensures a high-quality finished product.
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An automated discrete analysis system (link to product page) and ready-to-use solution kits allow winemakers a simple and effective way to monitor samples quickly and efficiently throughout the production process. Analytical methods for sugar and acid analysis were developed to follow international standards, such as those determined by the Association of Analytical Communities (link to AOAC page).
At Weinlabor Braun, a commercial wine analysis laboratory in Germany (link to laboratory page) about 10,000 samples are analyzed each year for sugars, acids, alcohol and sulfites. Finished wines labeled from this region must meet strict standards to be certified by the Chamber of Agriculture Reinland-Pfalz. Results for clients are provided with same-day service since all the necessary tests can be completed in about 30 minutes.
For more information about wine analysis, visit our Food Community, a wonderful resource dedicated to our Food and Beverage customers and featuring the latest on-demand webinars, videos, application notes, and much more. Also, visit the resources below.
- Application Note AN-71720, A Comparison Study of Total Acidity Methods for the Analysis of Wine, (Downloadable pdf)
- Case Study CS-71286, Testing time decreases ten-fold for a commercial wine lab in Germany, (Downloadable pdf)
- On Demand Webinar, Fast and Accurate Sugar, Acid, and Sulfite Analysis Using Automated Discrete Analyzers, (link to short registration page after which webinar will play)
Are you measuring sugars and acids in your wine samples, and is automated photometric determination of interest to your laboratory? If so, we would like to hear about your experiences.