Troubles et dépôts des boissons fermentées et des jus de fruits: aspects pratiques du diagnostic by D. Delanoe, N. Suberville

PREFACE

The quality of wine presentation is most often judged first and foremost on its clarity. This quality criterion must be maintained throughout the entire marketing process until consumption. The presence of turbidity or crystal deposits is not accepted. Generally, very good clarity is required by consumers regardless of the age of the product being tasted. Furthermore, commercial exchange standards are becoming increasingly strict regarding the number of residual microbial germs. To meet this demand, the winemaker must clarify and stabilize the wine in terms of clarity defects or physicochemical and microbial balances.

Hence the interest of this work, which aims to address the practical aspects of diagnosing issues and deposits in beverages. The objectives set by the authors Dominique Delanoé and Nathalie Suberville along with their collaborators Pierre Abasq, Patrick Bertrand, Sophie Letard, and Françoise Simon, are in line with current consumer expectations. These practical diagnostic aspects are timely; it is important, even more so today, to take stock of this matter. The stakes for the agri-food sector, and particularly the viticulture sector, are significant in a world where product development tends towards "zero defects," and where competition is increasingly fierce.

In this preface, I cannot ignore the work of Louis Pasteur in the 19th century. These works followed observations made during commercial exchanges between France and England, which almost led to a state affair.

In fact, an English merchant wrote to Louis Pasteur on October 29, 1863: "In France, people are surprised that the trade of French wines has not expanded in England since the Commerce Treaty. The reason is quite simple. We welcomed these wines eagerly, but we soon had the sad experience that this trade led to great losses and endless troubles due to the diseases they are prone to," and Louis Pasteur added, "I can assure you, which gives an idea of the extent of the problem, that there may not be a single cellar in France that does not contain some portions of more or less altered wines. Concerned about the harm caused by wine diseases to trade, the Emperor deigned to encourage me to direct my research on this important issue in order to discover, if possible, a way to prevent the occurrence of all these diseases."

Modern oenology has complemented and enriched the work of Louis Pasteur, and today there are simple rules to protect against the "multiplication of parasitic vegetations that correlate with wine diseases," and that "in the absence of these cryptograms, wine ages without alteration, if it is slowly and gradually exposed to the influence of oxygen from the air." Louis Pasteur reveals "that preventing wine diseases is simply about finding a way to destroy the vitality of the germs, the parasites that constitute them, in order to prevent their further development." He also predicts how easy it is to achieve this goal. These works explain and emphasize the role of hygiene in preventing bacterial contamination of wines. It is clear that obtaining clear and stable wines in bottles addresses concerns of the wine trade, faced with the unexplained and unpredictable formation of issues and deposits detrimental to the appearance of bottled wines and their marketing.

The clarity obtained after the elimination of particles is indeed rapid and immediate, but it is not necessarily definitive given the many natural phenomena that can occur in wine, which may be accompanied by the formation of a cloudiness or deposit.

Clarification can be natural, often induced (filtration-collage) to accelerate the natural process and achieve the desired state. Stabilization, on the other hand, aims to maintain clarity and prevent deviations or accidents during storage; it should not impede the normal and harmonious evolution or maturation of the wine. Clarification and stabilization are complementary steps, but a clarification operation is not necessarily stabilizing. Today, we are well aware of the chemical and biological mechanisms that can cause haziness or sediment. We can anticipate them; laboratory tests allow this, effective treatments are known and should be implemented when necessary before bottling. To achieve this goal, oenologists must have corresponding scientific knowledge, as the stability of colloidal particles depends on physico-chemical interactions. However, ensuring perfect stability of wines has become a marketing rule for the bottler, a quality assurance imperative demanded by the market.

New technological means have recently emerged that provide various preventive solutions available to oenologists, which can be physical, chemical, additive, or subtractive techniques.

This work, "Troubles and Sediments in Beverages - Practical Aspects of Diagnosis," meets all these objectives. It clearly shows that today the complexity of oenology does not allow a single researcher to encompass the entire discipline. This is partly why the authors Dominique Delanoé and Nathalie Suberville have surrounded themselves with competent collaborators. This book is intended for students as well as industry technicians. They should find theoretical interpretation, diagnosis, and practical aspects to address the problems encountered in cellar practices in order to define, among the proposed solutions, the most suitable ones for each situation.

I am convinced that this work will lead to clarification and stabilization processes for beverages and wines in particular, providing security for both the bottler and the consumer, without altering its origin.

It is a valuable collection and reference guide that practitioners, serving the market, must and will have at their disposal. I wish it great success, which I do not doubt, as it comes at the right time.