Titrimetry in Wine Analysis

There are various titrimetric methods from acid-base titration, where equivalence is determined by the point of neutralization, to redox titrations using an oxidizer and a reducing agent. Titrimetry can subsequently be deployed in a wide range of application areas, including for quality assurance and control (QA/QC) in winemaking.

The Role of Titration in Winemaking

As with many aspects of food and beverage production, winemaking is equally described as an art and a science. Every step of the craft is carefully monitored to maintain the highest quality standards that satisfy both consumers and regulators. This begins with initial viticulture, the cultivation and harvesting of grapes, and ends often decades later with a chemical analysis of the fermented product.

Titrimetry is a reliable technique for vintners investigating key diagnostic parameters relating to wine quality and content. It is valued for its ability to precisely indicate the quantity of various identifiable constituents including acids, esters, ethyl alcohol, salts, and various small molecule substances. These can directly impinge upon quality attributes, so titrimetric methods allow vintners to carefully control wine chemistry throughout processing to preserve the product’s integrity.

On-line titrimetry can provide timely insights into deviations in wine chemistry, providing a data-driven basis for altering the batch chemistry. There are two parameters that vintners typically assess using titrimetric methods: free and total sulfur dioxide (SO₂), and titratable acidity.

Measuring Free and Total SO2

Free total SO₂ combined with the pH level of wine help prevent oxidation and related spoilage, but molecular sulfur dioxide is gradually lost due to aeration and binding. Additional free SO₂ may help to extend the product shelf life, but it may also impart an unpleasant aroma/taste that is easily perceptible by consumers. Vintners often use titration to measure total SO₂ and carefully balance sensation with stability.

Additionally, the total sulfur dioxide—that is the entire concentration of free and bound SO₂ in the product—is regulated by the U.S. Alcohol and Tobacco Tax and Trade Bureau, so titrimetry is often used to prove regulatory compliance.

Determining Titratable Acidity

Owing to commercial limitations, vintners often use standard pH tests to measure titratable acidity, as total acidity and pH level are interrelated concepts. However, titrimetry can be used to measure the organic acid composition at multiple touchpoints in the fermentation process. This information can underscore a wide range of key business decisions, including harvest times, wine styles, and the diagnosis of post-treatments such as acidification.

Interested in titrimetry?

At RQM+ Lab Services, we specialize in QA/QC services for commodity and luxury goods, leveraging our unique analytical expertise to help you produce the highest quality products. If you are interested in using titrimetric methods to assess your products, why not contact us today?