The amount of acid present in a wine can directly affect its color and flavor, and can serve to balance the sweeter or more astringent wine components. This balance is challenging as too much acid may make a wine tart or sharp, while too little may make a wine flat or flabby. Proper acidity in wine is important to making the wine stable, palatable, with a refreshing accompaniment to food. The proper acid level of a finished wine can vary based on the wines desired style, with sweeter wines requiring slightly higher levels of acidity to maintain proper balance with their sweeter components.
Tartaric acid concentrations in wine range normally from 1.5 to 4.0 g/L. This acid concentration should not be confused with total or titratable acidity of wines, which are often expressed as tartaric acid content as well. Although it is the tartaric acid that is the predominant acid present, up to 60% of the total acidity, others like malic, citric, and several volatile acids contribute significantly to total acidity.
Hanna offers titration systems for measuring titratable acidity and a photometer for measuring tartaric acid.
Potentiometric titration of acidity can be done with an application specific minititrator that simplifies the measurement for the winemaker. Titrators are also available that can be programmed with multiple methods including one specific for wine that can measure sulfur dioxide, reducing sugars, and YAN.
Also available is the photometric chemical method. In this method two reagents are used in determining the concentration of tartaric acid less than 5.0 g/L (ppt). When both reagents are added to a sample containing tartaric acid, the sample will turn an orange-red hue; the greater the concentration, the deeper the color. The associated color change is then colorimetrically analyzed according to the Beer-Lambert Law.
Titration systems with precision dosing pumps are available to perform a titratable acidity titration. There are options for titrators with two analog inputs and two dosing pumps. This configuration allows for one channel to be used with a pH electrode and titrant for acidity titrations and the other channel for a ORP probe and titrant for the titration of sulfur dioxide.
An application specific titrator for wine is available for the measurement of tartaric acid. This meter uses pre-standardized titrants to simplify the measurement. With this system everything is included to measure tartaric acid.
Electrodes & Probes
The following are pH electrodes for use when performing the acid/base titration for tartaric acid. In this category is a pH probe with the Hanna Clogging Prevention System (CPS) technology that prevents clogging of the reference junction by solutions with a high solids content.
A portable photometer is available to measure tartaric acid. This meter includes all of the accessories to perform the test and is packaged in a rugged carrying case.
Solutions for tartaric-acid measurement include calibration and fill solutions for pH electrodes, storage solutions and application specific cleaning solutions for wine stains and deposits.
Accessories include replacement cuvettes and caps for the photometers. In this category are the replacement titrants used with the minitirators. Also included in this category are titrants for tartaric acid that can be used with most potentiometric titration systems.
Accessories for tartaric acid titration include spares for the minititrators. The spares include the replacement tubing set and valve, plastic beakers, and magnetic stir bars used for mixing.