Enology 1

A.Y. 2020/2021
Overall hours
Learning objectives
The teaching is aimed to provide an in-deep knowledge of the scientific principles underlying the wine production and based on the biological, physical and chemical needed to their comprehension. More specifically, Oenology 1 is aimed to provide the knowledge to successfully effect the transformation of grape into wine in a winery. The lectures will provide the formation needed to know and manage the machines used in the winemaking chain as well as the physical, biological and chemical phenomena involved with it, in order to understand the role of each process step and its effect on the product characteristics. The training activities applied for solving problems related mass balance, energy balance and kinetics, will reinforce the specific calculation ability. Moreover, the teaching will provide fundamentals to understand the special production techniques needed to obtain wine with peculiar sensory properties and described in the next teaching course Oenology 2.
Expected learning outcomes
In the end of the course the student shall know the composition of ripe and ripening grape, as well as the role of each grape constituent on the final properties of wine. Moreover, the student shall know the effects of the grape harvest, transport and wine making on the constituents of grape, must and wine as well as on the sensory properties. Students shall be able to lead the alcoholic fermentation and the variables affecting it. Moreover, he/she shall know and size the machines used in the winery a well as to understand their working principle and the effect on the final product. The student shall acquire suitable technical language properties.
The student will be able to size the wine making machines and their mass and energy balances. The student shall be able to describe the sensory properties of wine, to qualitatively assess them, and to use those data to tune the production process. The student shall be able to participate consistently to the wine making, as well as to make choices in agreement with the expected result. Finally, the student shall be able to attend the compulsory factory internship provided in the end of the course as fully aware of the assigned activities, correctly performing them as well as adopting a critical and rational approach. The student shall be able to write down a technical report concerning the activities carried out during the in-winery internship suitable to the final degree report.
Course syllabus and organization

Single session

Lesson period
The lessons will be held on-line, mostly in synchronous mode, using an appropriate platform (i.e., Microsoft Teams). The exercises will be held either on-line or in person; in the latter case respecting the rules of prevention against the Covid-19 spread (e.g. distance, mask, etc.). Recordings of the lessons will be made available to students. Virtual educational visits to industrial plants and/or wineries will be included. The examination rules provided for the in-classroom mode will be extended to the web mode.
Course syllabus
Lectures content of the first unit (Unit Operations)
- Definition of the wine production chain.
- Quantities. Unit of measurement, dimensions, dimensional analysis. Exercises.
- Mass balances: theory and exercises.
- Energy balances: theory and exercises.
- Heat transport by conduction and convection. Energy balances in heating and cooling operations. Steam table. Heat exchangers. Exercises.
- Evaporation. Types of evaporators. Mass and energy balances in evaporation. Heat economy and optimization. Exercises.
- Fluid mechanic. Hydrostatic pressure. Exercises.
- Fluid dynamic. Laminar flow and turbulent flow. Bernoulli equation and load losses. Fluid transport. Exercises.
- Settling: theory and equipment. Exercises.
- Centrifugation: theory and equipment. Exercises.
- Filtration: theory and equipment. Exercises.
- Distillation: theory and equipment. Examples of spirits and exercises.

Lectures content of the second unit (Principles anf fundamentals of wine making).
- Overview of red wine making process. Structure and composition of grape bunch and berry. Properties and oenological role of monosaccharides, organic acids, salts an anthocyanin.
- Grape flavanols and proanthocyanidines: distribution in grape, chemical structure, composition, size and properties. Meaning of tannin. Polysaccharides and cell wall structure. Interaction between tannin and polysaccharides.
- Evolution of sugars and acids over the ripening. Correlation between acidity and acid taste.
- Grape ripening and its effect on wine properties: evolution of cations, cell wall polysaccharides, native pectolytic enzymes, anthocyanin and proanthocyanidins from skin and seed.
- The concepts of ripeness (technological, phenolic and cellular). Methods for assessing the phenolic ripeness: spectrophotometric methods, colour indices, quantification of flavonoids.
- Comparison between handmade and mechanical harvest. Effect of the harvest on the grape properties. Role of the grape carrying system on the microbiological properties of grape must. Role and use of sulphite on the control of microorganisms.
- The cold and air-free transport of harvested grape. Sorting and rinsing grape systems. Role of destemming and machinery for achieving it. Grape crushing. Polyphenol oxidase enzymes: activity, distribution in the berry, substrate affinity, inhibition. Straight and indirect phenol oxidation and the role of sulphite.
- Ascorbate and glutathione as anti-oxidants. The managing of sulphite addition in grape must. Chaptalization: sucrose, concentrated musts and their production. Vacuum concentration. Reverse osmosis and spiral wound filters. Spray-dryer and RCM. Correction of grape must acidity: purposes and methods of pH and acidity correction. Use of acids and basic salts according to the law indications. The management of sulphite in grape must.
- The management of the alcoholic fermentation: role of yeast other than ethanol production, effect of temperature on Saccharomyces and autochthonous microflora, role of microbial count on the prevalence of Saccharomyces.
- Products of alcoholic fermentation: the CO2 and the health risk for the employees over the vinification. Fermentative self-heating and its effect on the cell membranes. The activity of ethanol an temperature: unsaturated membrane lipids and the role of sterols. The role of oxygen on the production of unsaturated lipids. Qualitative and quantitative aspects of grape must oxygenation.
- Yeast available nitrogen and its role on cell growth. Kinetics of nitrogen consumption and the related nutritional integration.
- The management of fermentation yeast inoculation and stuck fermentation.
- Overview of white wine making. The sensory properties of white wine. The management of harvest of for white wine making. Principles of grape pressing. Pneumatic membrane presses, vertical presses, the Coquard press pressing. The continuous presses: Archimedean's screw press, Branco press.
- Grape must clarification and its effect on the sensory properties of wine. Measuring system of must turbidity. The Stokes' law and the physical principles of the clarification methods. The role of hexogen pectolytic enzymes. Settling and floatation techniques. Lees filtration on vacuum drum filter.
- Cold skin maceration for white wine making. Calulation of heat balance for dry ice usage. Effect of cold skin maceration on terpene extraction.
- Physical-chemical phenomena involved with fermentative maceration. Co-polymerization phenomena of anthocyanin and proanthocyanidins: oxidative origin of ethanal. Fundamentals of phenolic evolution in red wine.
- Overview of the oxidative ageing of wine and the role of the anthocyanin to proanthocyanidins ratio. Kinetics of phenol extraction over the fermentative maceration. Role of maceration on the phenolic evolution of red wine.
- Extraction behaviour of grape skin and seed. Role of solid material, temperature, ethanol and mechanical force on maceration and phenol ectraction. Comparison between pumping-up and punching-down. Heat dissipation.
Prerequisites for admission
The knowledge provided over the lectures needs a suitable backgroung about a number of subjects of physics, yeast metabolism and wine chemistry. Therefore, it is appropriate that the student passed the exams related to Physics and Wine Chemistry.
Teaching methods
Regular classroom lectures supported by electronic slides, calculation exercises, practical training and technical tasting of wine, didactical visit to a factory producing machinery or products for winery.
Teaching Resources
- PowerPoint slides shown during the lectures and available on the ARIEL web portal along with the bibliographic references.
- Carlo Pompei. Operazioni unitarie della tecnologia alimentare. (2009) Casa Editrice Ambrosiana.
- R.P. Singh. Lectures in food engineering. (http://www.rpaulsingh.com/lectures/lecturelist.html).
- Handbook of Oenology vol. 1 and 2. Ribereau Gayon et al. (2018). Ed. Edagricole-New Business Media. Edizione 4.
Assessment methods and Criteria
The exam is composed by two partial parts: the first one is a written trial involving calculations related to the main unit operations, the description of processes and schematization of a simple equipment and its working principle. The second trial involves a short written calculation dealing with simple procedures possibly occurring in a winery; in case of passing, it's readily followed by an oral exam starting with a carefull description of a winery equipment.
Elementary operations
AGR/15 - FOOD SCIENCE AND TECHNOLOGY - University credits: 5
Practicals: 16 hours
Lessons: 32 hours
Principles and elements of enology
AGR/15 - FOOD SCIENCE AND TECHNOLOGY - University credits: 5
Practicals: 16 hours
Lessons: 32 hours
Educational website(s)
By schedule
Office (Building 21040 - entrance on side Room 4 - I floor)