Influence of the electrochemical potential in oenology

Influence of the electrochemical potential in oenology

Federico Casassa

The analytical parameters in oenology are a fundamental tool to take decision, during the wine making. Knowing the pH, allows us to know the acid-base balance of the wine, so in the same way the electrochemical potential (E) determines its oxide-reduction balance.

Redox (Electrochemical) potential

The redox potential or electrochemical potential allows us to obtain information on the oxide-reduction situation of a mixture, indicating whether the species found in it are in an oxidized or reduced state depending on their normal reduction potential (E0). Due to the large number of species present in the wine, during the wine production, we will not reach a balance, but an electrochemical potential that will evolve and on which we can act.

Combined with oxygen

Excessive oxygen supply in wines can lead to problems with colour evolution, disappearance of varietal aromas or the development of unwanted microorganisms. However, there are moments, when oxygen contribution would be beneficial for the wine. Controlling the evolution of the oxide-reduction potential we can adjust these doses in each moment. With adequate doses, we will not observe an alteration of the E, but, we will obtain increases of up to 150 mV, if the oxygen supplied is greater than normal dose.

Combined with nutrition.

A good nutritional protocol along with good redox potential management will help us obtain good fermentation kinetics, which improves the fermentation safety and avoids the appearance of reduction aromas.

The addition of nutrients in the form of ammonium salts accelerates the fermentation kinetics, considerably decreasing the E and leading to the appearance of reduction aromas. The use of organic nutrients is therefore recommended since they increase the YAN without considerably affecting the E.

Marcia Torres

After several years monitoring the redox potential throughout the process, Marcia has acquired the necessary experience that allows her to make important decisions such as:

  • Decide the moment and type of nutrition during fermentation
  • Make more responsible use of sulphur dioxide additions, based on the tendency of the wines to oxidation or reduction
  • Decide the optimal time for bottling, increasing the longevity of the wines and defining the aromatic profile

Measurement of redox potential during fermentation

The speaker will present his experience with monitoring the electrochemical potential during fermentation. With this measure it can foresee the appearance of reductions and using the necessary oenological tools to modify the potential depending on the desired objective.

During the presentation, continuous measures of the electrochemical potential and its influence on reduction aromas will be shown.

Responsible use of sulphur dioxide

The speed at which different oxidation reactions occur in wines is influenced by the electrochemical potential. When a wine has a low potential, the RedOx pairs of the wine will tend towards their reduced state, on the other hand, when the potential is high the tendency of the compounds of the wine will be directed towards oxidation. This mechanism allows you to decide when and how much sulphur to add, limiting additions during all storage and prior to bottling, resulting in wines with lower total sulphur content in bottling.