INDICE
This informative article, produced by the Infowine editorial team, was excerpted from the webinar ‘Cellar Hygiene and Critical Points for the Prevention of Microbiological Defects’ (in Italian) given by Christophe Gerland | Intelli’oeno.
For further insights watch the original video, accessible with the Infowine Premium subscription.
Cellar Sanitisation: Basic Principles
Sanitisation in oenology is a process that is not only recommended but essential to maintain cellar hygiene and ensure that wine meets quality and safety standards. This article explores the concepts of cleaning and disinfection as distinct but complementary elements in the winery sanitisation process, focusing on the thorough cleaning procedures and microbiological controls required to produce high quality wines without defects. With these hygiene practices, the winemaker can prevent frequent microbiological problems such as the proliferation of Brettanomyces and ‘’mousy taste‘’.
Cleaning and Disinfection: Two Indispensable Steps
Cellar sanitisation consists of two fundamental and complementary phases:
Cleaning: Elimination of visible dirt, essential to deprive micro-organisms of their growth substrate. This phase involves the use of specific detergents that allow the water to reach all critical points.
Disinfection: Reduction of micro-organisms to acceptable levels through the use of chemical or physical agents. Disinfection must be preceded by thorough cleansing, as disinfectants are ineffective on dirty surfaces. Only in exceptional situations is it possible to combine the two phases.
Sanitisation is not limited to the removal of visible dirt, but must also ensure the biological and chemical safety of surfaces, avoiding chemical residues and keeping the microbial load at controlled levels.
The Importance of Cleaning
Cleaning is the first and indispensable step in the sanitising process:
Mechanical removal: Removing the bulk of dirt by hand is essential, especially on surfaces that have been in direct contact with wine.
Initial rinse: Using warm water at about 45-55°C helps to remove fats without damaging the surface, keeping the detergent more effective.
Application of the detergent: Since many organic residues are not soluble in water, a detergent that can break the bond between dirt and surface is required to allow effective rinsing.
Final rinse: This should be done with water at room temperature to avoid detergent residues, which could alter the taste of the wine or neutralise subsequent disinfection treatments.
Detergents, largely composed of surfactants, increase the wettability of the water, allowing it to reach hard-to-access corners and surfaces, and help keep dirt particles suspended until they are removed.
Key Detergent Factors: The TACT Principle
The effectiveness of cleansing depends on four key factors:
Temperature: warmer water (45-55°C) improves the cleansing power. In the case of detartarisation, the difference in efficiency between water at 12°C and 36°C can quadruple.
Mechanical action: Wash heads and foam channels distribute cleaning agents evenly, improving cleaning efficiency and reducing the need for water and detergent.
Concentration: It is essential to follow the detergent manufacturers’ instructions to ensure maximum effectiveness.
Contact time: Increasing the action time of detergents, when necessary, compensates for any compromises in concentration or temperature.
Disinfection: Key to Cellar Safety
Factors Influencing the Effectiveness of Disinfection
The effectiveness of a disinfection intervention is influenced by crucial variables:
Concentration of the active ingredient: Increasing the concentration of the germicide improves efficacy, but it is important to dose accurately so as not to alter contact surfaces.
Type of microorganisms: The sensitivity of microorganisms to disinfectants varies greatly; disinfectants must be selected according to the specific needs of the cellar (e.g. bactericides, fungicides).
Contact time and temperature: These factors influence the effectiveness of the treatment. Some disinfectants work better at higher temperatures, others retain their action even at low temperatures.
Solution pH: The chemical composition of industrial disinfectants is optimised to work at specific pH ranges, thus ensuring maximum effectiveness against the microorganisms present.
Surfaces and residual dirt: Disinfectants are most effective on perfectly clean surfaces; any residual dirt acts as a barrier, protecting microorganisms from contact with the disinfectant.
Winery Disinfection Strategies
To ensure complete disinfection it is necessary:
Remove stubborn incrustations with high-pressure water jets before disinfection. This prevents dirt particles from remaining that could impair the effectiveness of disinfection.
Use disinfectants with different microbiological actions (virucides, bactericides, fungicides), specific for cellar pathogens, such as bacteria and fungi from grapes and transport media.
The choice of specific disinfectants is crucial in the cellar, where the variety of pathogens and the varying sensitivity of microorganisms require versatile but effective solutions.
Microbiological Control and Monitoring in the Cellar
Rapid Monitoring Techniques
The verification of hygiene conditions in the cellar using rapid monitoring techniques is essential to avoid microbiological defects in the wine. Among the techniques used are:
ATP-metry: Allows microbiological activity to be measured by ATP, a molecule present in all living organisms, using a luminometer that detects the light emitted by the chemical reaction with ATP.
Petrifilm and contact plates: They visually detect the presence of bacteria on surfaces in contact with wine, and are useful for quick checks at critical stages of production.
For accurate monitoring, these techniques are complemented with more specific methodologies, such as microbiological culture.
Advanced Techniques for Detecting Brettanomyces
Brettanomyces, microorganisms responsible for numerous aromatic defects, can be detected using advanced techniques such as:
Microbiological cultures: Samples taken are incubated in specific culture media, and any growth indicates the presence of Brettanomyces.
PCR and flow cytometry analysis: PCR (polymerase chain reaction) detects traces of bacterial DNA with high precision, while cytometry visualises live microorganisms, showing specific active microbial populations.
The combined use of these techniques gives a complete picture, ensuring an accurate diagnosis of the level of contamination.
See also how to effectively control Brettanomyces and bacterial contamination!
Optimising Resources: Water Management in the Cellar
Cellar sanitisation requires a considerable amount of water, a precious resource that entails both supply and disposal costs and a significant environmental impact. Each litre of wine produced requires between 2 and 5 litres of water, depending on the cleaning practices adopted. It is therefore essential to take measures to reduce water use during sanitisation without compromising hygienic effectiveness:
Efficient washing heads reduce water consumption by optimising the distribution of detergents on surfaces.
Wastewater recovery: Water treatment technologies allow washing water to be reused for further treatment, reducing costs and environmental impact.
Case Study: The Importance of Water Quality for Sanitisation
The water used in the winery must be microbiologically and chemically pure to prevent contaminants from altering the taste, aroma or colour of the wine. Sanitising with low-quality water greatly reduces the effectiveness of the process, as part of the sanitising effect is lost in the neutralisation of micro-organisms already present in the water itself. In cases where the water does not meet oenological standards, treatments are recommended to purify it and make it suitable for use in the cellar.
Critical Sanitisation Issues and Suggestions for Improvement
Despite the importance of sanitisation, there remain some critical points that may hinder proper hygiene in the cellar:
High water consumption: Optimising water use is a priority to reduce the water footprint.
Aggressive detergents: Some detergents can be corrosive and dangerous. It is important to use them according to specific protocols to avoid damage to operators and equipment.
Unsuitable equipment: Some traditional cleaning equipment, such as pumps and tanks, can retain particles and biofilms that hinder thorough cleaning.
Through technological solutions and the adoption of detailed protocols, it is possible to overcome these challenges and ensure complete and safe sanitisation.
Did you know that some producers have started using cellar wastewater to irrigate their vineyards
Conclusions and Recommendations for Effective Sanitisation
Cellar sanitisation is a complex but essential process for producing quality wines. Integrating cleaning and disinfection techniques with regular microbiological monitoring allows a hygienically safe environment to be maintained, preserving the organoleptic quality of the wine. Innovations in cleaning equipment and advanced monitoring methods help optimise resources and reduce environmental impact.
To learn more about sanitation techniques in winemaking, watch the full recording of the webinar, where all the new developments in winery microbiological control are explained. The recording is available for purchase-don’t miss this advanced training opportunity!
