Problems and solutions
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Stuck fermentation
This delicate issue has occupied our Department of Research and Development for the last three years. Applications have been carried out in the cellar under extreme temperatures and alcohol levels, resolving the cessation of fermentation in Amarone wine.
This experience has resulted in the EV Procedure for stopped fermentation. Our technical staff is available to provide you with further information.
Brettanomyces and wood sterilization
In 2001 Enologica Vason and the University of Verona began a research project to detect the presence of Brettanomyces in wine. The result of this project is a set of analyses that is available to the clients of Enologica Vason, which allows them to perform practical microbiological and chemical analyses through the examination of ethyl phenols.
The chemical analysis is done by extraction with an organic solvent, and the constituents identified by gas chromatography with a mass spectrometer, which can indicate an advanced state of contamination.
The microbiological analysis allows the winemaker to determine the beginning development of Brettanomyces, and also indicates how to prevent organoleptic spoilage due to the growth and metabolism of the Brett yeast.
Enologica Vason offers a direct monitoring system for the cellar that will detect the presence of Brettanomyces both on surfaces and in the wine.
A EV Procedure for wood sterilization is under development.
Through experimentation we have developed a specific medium for the selective identification of Brettanomyces, which is now available in agar form.
Premature decay of wineThe premature decay of wine is related to its structure, its composition, and the amount of oxygen that is liberated during its development prior to bottling.
Premature decay can be prevented by:
High alcohol (>13°) fermentation
There is a trend in viticulture toward wines with great structure, body, and a relatively high alcohol level. Nevertheless, the yeast strains that are currently used were not bred for this purpose. A novel way to deal with this is to put greater emphasis on the rehydration and preconditioning of the yeast in a special “pied de cuve” (see Easyferm), and to attentively apply a second yeasting. The details are collected in the EV Procedure for sequential fermentation, developed by the Department of Research and Development through the fermentation of Amarone.
Premium® Fructo is the recommended yeast for the second inoculation. Our technical staff is available to provide you with further information.
Sluggish fermentation
Fermentation has started, but it has difficulty taking off or it is sluggish.
It can be revitalized by injecting a dose of oxygen (Macrodue), and by intervening with nitrogen and adsorptive substances (Fosfoactiv Premium® e Solfoactiv Premium®).
If the alcohol level is not greater than 9°, the solution is a second yeasting with Premium® Fructo, specifically carried out according to EV Procedure for sequential fermentation.
Calcium in wine
If calcium is present above a certain concentration, it can precipitate out, typically forming a whitish sediment.
This situation can be ameliorated by a technique that was recently included as an authorized enological treatment, i.e. tartaric stabilization through membranes (electrodialisis: EU Reg 1493/99, IV, art. 4, B).
Another possibility to reduce calcium in a solution is to add Cristallite® Special. The technical description for this product contains detailed information about its use.
Filterability Index
The filterability index is currently the only parameter that can provide a valid measure to evaluate the filterability of a liquid. It determines the obstructive capacity for a wine in all its aspects. A wine with a favorable index can be micro-filtered without the risk of blocking the cartridges.
The filterability test is an integral part of a certified system for quality control. It is used to define the efficacy of clarifications and filtrations.
Gruppo Vason offers two semi-automatic systems to conduct the test: Q.F.T. and Quality F.I.T.
Cartridge obstruction
Some materials can be restored with detergents, others with only water or steam. Many different materials can cause blockage and there are many different degrees of obstruction.
Our technical staff is available to offer you additional information and to suggest the best solution for each individual case. Gruppo Vason does not manufacture membranes, but we can give you all the necessary information for their technical and economical management.
We offer a variety of products:
A filterability test will always help prevent premature obstruction of the cartridges.
Malolactic fermentation will not start
Once the classical analytic parameters have been controlled, it may be advisable to use a specific activator to prime the start of bacterial activity (Malo Activ).
The use of LPA® together with Mannozym® is another solution, which permits a rapid dissolution of micro-elements that stimulate microbial activity.
We offer ready-to-use bacteria as a freeze-dried culture for direct inoculation: Amar04®, a strain selected by the University of Verona from Amarone and produced exclusively for Enologica Vason by Christian Hansen.
Ochratoxin contamination
The presence of ochratoxin A in wines has been problematic already for several years. The Department of Research and Development examined the adsorption effect of enological adjuvants in the presence of this molecule. This research has generated two products to address this problem: Micosorb and Micosorb plus.
Protein stabilization
The use of tannins as clarifying agents is often responsible for the sensory modification that results after applying the required amount.
Protein stability in white wines can be achieved through the use of specific tannins such as Premium® Uva or Premium® Stab, which are more reactive than the proteins themselves. These tannins are able to preserve the organoleptic character of the wine from the start, without weakening its structure.
Another, more traditional way to stabilize proteins is bentonite, still considered the ultimate fining agent. Our product list contains natural sodium bentonite (Plusgran V®), and activated bentonites in granular form (Plusgran V®) or in powdered form (Flottobent®, V Bentonite & Bentonite Special). The first three can be used in micro-doses because they possess highly enhanced fining power.
Evaluation of protein stability
In the bibliography you can find several methods for evaluating if a product is protein-stable, or for estimating the amount of bentonite necessary to achieve stability.
The Department of Research and Development has conducted its own tests of the validity of these various methods. Please see the section Proteotest e Bentotest, where you will find useful information.
Tartaric stabilization
Finally there is a definite solution to the problem of tartaric stability. For all too long, one had to follow tables derived from technical calculations on model solutions, which were difficult to reconcile with the reality of the wine cellar. The answer is tartaric stabilization through membranes (electrodialisis: EU Reg. 1493/99 IV, art. 4, B), which can be used for all types of wine (IGT, VQPRD, DOC, DOCG). The treatment occurs at room temperature and guarantees the stability of the wine while leaving its color and structure unaltered.
Traditional solutions always refer to the use of refrigeration, which turns out to be important for accelerating the growth of crystals on potassium bitartrate nuclei. An alternative solution is Cristallite® Special, a complex product developed to help the formation of emerging crystals.
Evaluation of tartaric stability
Too often tables and theoretical calculations are not really useful in the evaluation of the actual stability of a wine. Every wine must be evaluated separately by its own characteristics.
Among several automatic tests, the Criotester represents the definitive solution for evaluating:
- if a wine needs to be stabilized
- the propensity of a wine to be stabilized
- the temperature at which one can see crystals form in the natural state of a wine
Sterile bottling
Since its foundation, Gruppo Vason has dedicated itself to the microbiological stabilization of wine at low temperatures through micro-porous membranes.
The first realization of a completely automated system (Sofos) dates from 1998. It is managed through a PC interfaced with the filler. Once Sofos is installed inline, it runs independently. It performs an integrity test of the membranes, and controls the sterilization, filtration, gas leakage, C.I.P. cleaning, restoration of the filter cartridges, etc., storing all important parameters in its memory.
The need for such a system arose from the awareness that to neglect any of the operative parameters would be enough to compromise the quality of the product and/or the longevity of the membranes.
For manual systems a definitive solution requires that all the variables be evaluated: filtering materials, detergents, sanitizers. The most important aspect always turns out that the procedures be tailored to every single user.
The first step is to verify the facilities of the cellar (cold water, hot water, steam, gases available…) and then decide on the strategy of installation, together with the client.
We have manuals on micro-filtration that refer to specific products (V Sanex®, Biocida V®).
V Sanex® Foam is used in the bottling industry for the sanitation of surfaces.
Spray Barrique, although its commercial name can be misleading, is also recommended for cleaning and sanitizing bottling equipment.
Our technical services include on-site microbiological monitoring on request. We offer innovative materials to perform independent microbiological analyses in the cellar.
Difficult-to-filter wines
The colloidal component of wine is a parameter that is difficult to interpret. Micro-filtration of a wine where the colloidal component is not known, could result in obstruction of the filters.
The most endorsed method for the estimation of the filterability of a liquid is the use of filterability indices. Gruppo Vason offers two semi-automatic systems for the execution of such a test: Q.F.T. and Quality F.I.T.
If the wine does not have a sufficient filterability index, one can intervene in several ways. Filtration and clarification always tend to degrade the structure of the wine.
To know which elements will be removed from a wine during a treatment, it helps to know the surface electrical charge of the clarifying agents and of the filtering elements.
With the use of an instrument called an SCD, clarification procedures can be optimized. Additionally, filtration adjuvants such as the cellulose V Cellplus have the right electrical charge, and thus can be an efficient way to improve a wine’s filterability. Modern research has made a new generation of inert filtering membranes available, which improve the filterability, while leaving the structure and body of the wine being treated intact (see tangential filtration).
The Department of Research and Development is able to address any of the following topics from the list below or additional topics of common interest, for join developers.
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