PRESENTATION OF CILYO
1. The evidence : the acceleration of aging phenomena
The oxidation of white and rose wines is a common phenomenon usually occurring within 6-12 months post-harvest.
This oxidation can result in color changes (turning golden, or slightly pink or brown), taste characteristic changes (astringency and dryness) and aromatic alterations. Such changes lead to a devaluing of the final product and ultimate loss of consumers.
This phenomenon mainly affects wines rich in polyphenols, whether from traditional pressing or inert pressing.
In recent years, a sharp increase in this phenomenon has been recorded. Oxidation now affects wines that were originally thought to have an aging potential of 10 years but that are now suffering from rapid evolution (within 3 years) toward oxidation.
The reasons behind this increase are numerous and indeed interconnected. The observed wines all have in common the increased synthesis of polyphenols in the grape, as well as their level of extraction in the musts. Among others, we can cite the following variables:
- Time of harvest, moving toward a later maturation,
- Lower yield
- Changing climate,
- Changing conditions of pressing (less and less use of “open cage” presses)
The key to reducing this phenomenon is therefore to first prevent the synthesis of polyphenols (using proper pruning techniques) or at the very least, choose appropriate pick dates, with regards to the polyphenol parameter, for your specific grapes.
The sensor system, Dyostem®, through its color index display (inversely correlated to polyphenol concentration) and the volume of berries, is a tool that allows a more precise and informed selection of harvest date relative to this new parameter.
The management of polyphenol extraction throughout pressing is also essential, particularly in the separation of juice.
If these two steps are properly executed, the management of polyphenolic potential is reasonable, making it easier to avoid all subsequent oxidative deviation in the wine, as well as to facilitate the management of sulfites.
To treat the separated juices that are richest in polyphenols (hard presses), two alternatives are available to the winemaker : fining (using PVPP, gelatin, etc.) or physical treatment with oxygen.
2. The concept : simulating a reaction to understand the limits
The treatment of musts with oxygen rests on the utilization of enzymatic activities of the grape for the purpose of eliminating a portion of the polyphenols. The enzymes put onto play (polyphenoloxidase first) provoke the oxidation of the polyphenols, which precipitate in the form of brown pigments.
The overall reaction is now well known and in fact many times the subject of publications (Rigaud et al, 1991, J Sci Food Agric).
During this process, certain formed compounds are susceptible to reacting with varietal aromas and ultimately destroy them.
The technique of oxygenation of musts was much practiced during the 1970s, using massive doses of oxygen, hence the name of hyper-oxygenation. These very large doses caused the systematic elimination of much of the polyphenols present in a must, but unfortunately, often took potential varietal aromas as well.
The work of Vivelys showed that the introduction of reasonable and adapted doses of oxygen to a must can, on the contrary, turn out to be interesting in stabilizing the future wines vis-à-vis premature oxidations, without destroying the aromatic potential of the product. This new technique, called “Controlled Oxygenation of Musts,” necessitates the systematic determination of the optimum amount of oxygento provide for the treatment of each juice fraction/separation. In response to this essential need, Vivelys has developed a device, Reactor O2CM, to precisely measure this amount of oxygen.
3. The operation principles of Cilyo
Cilyo is the result of nearly ten years of experimentation in both hemispheres. Our objectives were to validate the benefit of the technique, but also to offer winemakers a simple way to determine the O2 needs of their musts.
The Cilyo allows the enzymatic reaction of the oxidation of polyphenols. For this, a sample of must to be processed is taken in an inert manner using accessories developed specifically by Vivelys. To allow this reaction, the must should of course be free of any antioxidant, such as ascorbic acid and/or SO2.
This sample is transferred into the Reactor O2CM where it then undergoes injection of oxygen. From there, the evolution of dissolved oxygen is followed.
A mathematical formula is then formed based on the rate of oxygen consumption observed in the must and the volume of oxygen injected, ultimately determining the optimal dose for treating the must.
This mathematical treatment determines the dose in about twenty minutes with a precision to the order of 1 ml/L (compared with the dose determined at the end of the reaction).
CHALLENGES IN WINEMAKING
The business plan of Vivelys is to develop and market management tools that permit winemakers and enologists to reach a predefined target product.
The oxidation of wines, especially of white and rosé wines, has the effect of taking the final product away from this predefined target, often confusing consumers in relation to what they expect from a particular wine, or worse, getting pulled from the competitive market entirely.
The proper and thorough management of this oxidation phenomenon will therefore provide solutions to the numerous challenges found in production.
1. The technical interest
At the base, the interest is in limiting negative aspects of premature oxidation of wines, including the loss of aromas over time.
Most winemakers, at some point, have been faced with the negative evolution of a tank where at the end of alcoholic fermentation there was indeed aromatic intensity, yet, after 6 months, the wine no longer possessed these original qualities.
The technique of controlled oxygenation of musts, performed with doses determined by the Reactor, can significantly reduce this aforementioned phenomenon and thus preserve the potential of wines.
2. The economical interest
In addition to preserving the aroma of wine, a better grasp on this phenomenon should allow even the last juice separation to be promoted to its greatest value potential, which up to now has often surrendered to the most basic of wine profiles.
Thanks to the accurate determination of a must’s O2 requirements, and the application of this dose before fermentation, it is now possible to enhance press juices, including those of fragile thiol-rich aromatic varietals such as Sauvignon Blanc.
However, depending on the mode of selection of juices, this fraction can represent up to 20% of a lot.
As the price of a liter of Sauvignon Blanc is significantly higher than a fermentative white wine (or even the same if it is sold after 6 months of aging), the recovery and promotion of these presses gives a clear competitive advantage to those who have mastered the controlled oxygenation of their musts.
Moreover, this technique can overcome numerous winemaking challenges with much more efficiency than adding fining materials such as PVPP and various anti-oxidants.
Controlled oxygenation of musts can therefore limit and even replace the addition of fining agents to your wine!
3. Experimental trials
To support the reasoning behind strategic O2 addition between pressing and the start of alcoholic fermentation, we have performed numerous micro-vinifications where the O2 dose determined by the Reactor was tested.
These micro-vinifications were performed in our experimental cellars (Domaine du Chapître in France and Capilla Lenclos in Chili) using a diverse array of varietals, such as Chardonnay, Sauvignon Blanc, Gros Manseng, etc.
These trials systematically included an untreated control and several experimental groups exposed to varying methods of treatment and different oxygen doses.
A sensory evaluation followed by polyphenol laboratory analysis were routinely performed.
The results obtained showed that the amount of oxygen provided to the must induced significant changes in its organoleptic qualities. This dose must be systematically measured because oxygen addition is extremely dependent upon varietal, the type of winemaking process to be used, and the juice segment that is being considered (ex.- free-run vs. hard press).
To have more information on the Reactor and the results of our experiments, please contact Alexandre Remy at ar@vivelys.com or on his cellphone 707 481 8114