The Importance of Analytical Testing in Winemaking

For thousands of years, vintners have harnessed a complex system of living organisms and biochemical processes to make wine. While the beverage has evolved over time and styles have diversified, the fundamental process of making a wine has stayed the same: Yeast ferment the sugar in grape juice, transforming it into ethanol, carbon dioxide, and heat.

The art of winemaking lies in knowing how to use different grape varieties, yeast strains, and production steps to create distinctive styles that are recognized for their aroma, taste, and appearance. Those traits, however, result from complex interactions among the growing conditions of grapes, their biochemical makeup at harvest, the reactions that occur during fermentation, and the biochemical development of must, juice, and wine during processing. Any imbalances in these interactions during production—from vine to glass—can alter the outcome and decrease the quality and palatability of a wine.

The wine market is highly competitive, and brand loyalty hinges on creating distinctive and enjoyable experiences again and again. Therefore, a winery’s success comes from deftly orchestrating vinification to preclude imbalances. Ensuring customer satisfaction and building brand equity means making timely decisions that steer winemaking toward the exact experience a vintner aims to create.

Data Enables Time-Critical Decisions in Winemaking

When it comes to creating premium wines, there is no substitute for the experience and knowledge of a vintner. But complementing that expertise with a precise characterization of the biochemical changes occurring in a batch better informs decisions to optimize production, ultimately boosting wine quality and selling price. Analytical testing at all production stages is the key to such data-driven decisions. Sensitive, easy-to-use analyzers allow the vintner to monitor the material composition and conditions of biochemical reactions and identify when and how best to intervene. Imbalances can be anticipated and corrective action can be tailored to reestablish ideal conditions in a timely manner.

Analysis is crucial from the beginning of the winemaking process, even while grapes are still on the vine. A refractometer can be used to measure grape sugar content and thus determine the best harvest time. Sugar and organic acid content should also be measured in grapes brought in from external sources, as these parameters typically vary with growing conditions (e.g., temperature, soil type, rainfall). Different wine types and varietals build on different acid-to-sugar ratios, and a suboptimal biochemical starting point can lead to a stuck fermentation that falls short of reaching the necessary final gravity.

Dedicated electrodes can be used to accurately measure the pH, organic acids, and nitrogen content of must. The results can better guide the use of additives to promote fermentation and control pH, while preventing an imbalance in acidity that can derail the flavor, color, and microbial stability of the wine. Sulfur dioxide, which is used as an antioxidant and inhibitor of microbial activity, can be monitored to prevent an excess that dulls fermentation and lowers wine quality. Finally, hand-held devices can measure liquid turbidity and dissolved oxygen in barrels and bottles to ensure desired clarity and prevent excessive oxidation that discolors and degrades wine flavor.

Analytical needs vary from one winery to another. Therefore, the first step toward establishing a cost-effective analysis infrastructure is to systematically evaluate the type and frequency of testing that best serves production procedures.

Design an Analytical Testing Plan

A range of advanced, easy-to-use, and highly reliable analytical instruments make measuring critical winemaking parameters straightforward. Designed to withstand the wear and tear of a manufacturing floor, these analyzers enable testing of a few to several hundred samples, either in a lab or directly at vines, vats, or barrels. The choice of instrument depends on three factors: the number of bottles produced at a winery, the frequency of measurements needed throughout the production process, and the vicinity of an accredited food analysis and safety lab. The latter point is important; waiting for results to return from an offsite lab can be the difference between a successful batch and one that is downgraded or lost. At a minimum, a wine producer should consider quantifying the parameters listed in Table 1 (see p. TK) on site, because changes usually require quick corrective action.