Patent Application
20080026100
Embodiments shall be hereunder described, given for indicative and non-limiting purposes, to illustrate the method for the production of a wine that is free of added sulfites according to the invention, and a wine obtained from such a method.
The test involved the grape harvest of 2005. Inzolia cultivar grapes, from the province of Trapani (Italy) were used.
The must obtained from 450 quintals of grapes from grape crushing was cold clarified for 24 hours by traditional methods and exhibited low acidity, high pH and a medium microbial load (Table 1).
The clarified must was thus racked and divided in a first and a second batch of 80 hl each. The acidity of the must was adjusted in both batches with tartaric acid.
The first batch of clarified must was treated in a suitable reactor by the method of the invention while the second batch (or reference batch) was treated in another reactor, for comparison, according to a conventional method involving the addition of sulfur dioxide.
More in detail, according to the invention, 15 g/hl based on the volume of the grape must of Excellence Gold White tannin (Oliver-Ogar) were added to the first batch to prevent it from oxidation.
Separately, a solution of granular type lysozyme for winemaking was prepared in situ by dissolving 1200 g of the commercial product Lysozyme food grade with activity >95% from Fordras SA in 12 l of water. The thus prepared solution was brought to 60 l with must and then it was added to the reactor containing the first batch, after a holding time of 5 hours from the time of addition of the tannin, in a quantity such as to obtain a lysozyme concentration in the must of 25 g/hl. The addition of lysozyme to the first batch was completed within about one hour.
To both clarified must batches were added 15 g/hl of yeast and 20 g/hl of fermentation starter culture for the second batch (reference batch) and double the amount for the first batch. According to the conventional method, 3.5 g/hl of SO2 were added to the second batch. The fermentation was left to proceed in both batches for 14 days at 18° C. at atmospheric pressure.
Such starter culture inoculum in the batch treated according to the invention enabled the fermentation to rapidly start. A higher rate of sugar use up and completion of the fermentation (reducing sugars <1 g/l) 36 hours faster than the reference batch were also observed.
At the end of the alcoholic fermentation, the wine obtained according to the invention had maintained the original quantity of malic acid more or less unaltered (please see Table 2 below) just like the wine obtained from the traditional method which was being compared, thus confirming the efficacy of the lysozyme in the control of the malolactic flora.
As far as the sulfur dioxide content is concerned, it is notably less in the wine of the invention and is originated exclusively by the metabolism of the yeasts, given that no addition of sulfur dioxide is involved in the method of production in this case.
At the end of the fermentation, 5 g/hl of SO2 were added to the reference wine and both wines were stored for 3 months in inert atmosphere (nitrogen) and then suitably stabilized and bottled. The chemical and microbiological stability of the wines under comparison was then compared. The results are shown in Table 3 below.
Table 3 shows that for both wines the bacterial stability control lasted beyond the storage period without significant variations in the general acidic profile. It is worth noting that the reference wine exhibits an increase in the figure for volatile acidity, given by the increase in the level of acetic acid population in the wines. As far as the protection against oxidation is concerned, the values for optical density were similar in the wines under comparison, which shows the efficacy of the tannins in preserving the wines from oxidation, which adversely affects their aroma and color (darkening).
The test involved the grape harvest of 2006. Merlot cultivar grapes were used.
The must obtained from 450 quintals of grapes from grape crushing was brought to a temperature of 16-18° C. and was then cold clarified for 24 hours by traditional methods.
The must was then transferred to a suitable reactor and a Proantocyanidinic tannin, Excellence Vintage (by Oliver-Ogar) was then added at the bottom of the must reactor at a rate of 30 g/hl of must to prevent it from oxidation.
Separately, 25 g/hl (based on the volume of the must) of “Selezione Italica 337” yeast (Oliver-Ogar) inoculum was rehydrated in water in a 1/10 weight ratio. The obtained yeast inoculum is then added to the first 10% of the must.
Separately, a solution of granular type lysozyme for winemaking was prepared in situ by dissolving 1200 g of the commercial product Lysozyme food grade with activity >95% from Fordras SA in 12 l of water. The thus prepared solution was brought to 60 l with must and then it was added to the reactor containing the must, after a holding time of 24 hours from the time of addition of the tannin, in a quantity such as to obtain a lysozyme concentration in the must of 30 g/hl. The addition of lysozyme was carried out concomitantly with a conventional delestage protocol.
The fermentation was then started and left to proceed for 14 days at 16° C. at atmospheric pressure.
At the end of the fermentation step, 20 g/hl of lysozyme was again added to the wine obtained, followed by extended maceration and the addition of 5 g/hl (based on the volume of the wine obtained) of Proantocyanidinic tannin, Excellence Vintage (Oliver-Ogar), and of 5 g/hl (based on the volume of the wine obtained) of Quebracho tannin, Excellence Brown (Oliver-Ogar).
Micro-oxygenation was then carried out on the wine obtained, at a rate of 10 ml/l/month for 15 days.
This was followed by the inoculation with 1 g/hl based on the volume of the wine obtained of malolactic bacteria upon which the concentration of malic acid was monitored until a drop in concentration to 0.2 g/l was obtained. 40 g/hl (based on the volume of the wine) of lysozyme was then added to stop the bacterial activity and finally, one week after the addition of lysozyme, 30 g/hl of Excellence Brown (Oliver-Ogar) tannin was added to the wine.
The final concentration values of malic, lactic, acetic and total acid, sugar, SO2, and alcohol by volume, lysozyme and pH in the wine obtained are summarized in Table 4.
In conclusion, the winemaking method according to the invention has been shown to be suitable for the obtention of wines free of added SO2. The inoculum of the selected yeasts enabled a rapid and complete course of fermentation. The control of the lactic acid flora was ensured during both the fermentation steps and the storage and could be further enhanced by the optional subsequent addition of lysozyme at the end of the fermentation.
Moreover, the wines obtained by the methods of the present invention have a vivid color and have an appearance that is comparable to that obtained from traditional production methods that involve a sulfiting step.
Moreover, the wines possess a pleasant bouquet and a flavor that is satisfactory and typical of the type of grape from which they are obtained.
It is thus clear from the description and from the examples given above that the winemaking method of the present invention (and the wines thus obtained) offers considerable advantages over the prior art. In fact, thanks to the method of the present invention, the addition of sulfites in the winemaking production method is no longer required.
Tannins and lysozyme, added separately according to the present invention, carry out an activity having an advantageously complementary effect once they are both added in the grape must. Their combined actions, in fact, can entirely replace the traditional addition of sulfites, thus guaranteeing microbial stability and the organoleptic characteristics of the wine so that it is no longer necessary to resort to a sulfiting step.
This is advantageous in that the resulting product does not exhibit the drawbacks deriving from the addition of sulfites, such as the manifestation of their toxicity and of their intolerance.
Moreover, the product obtained will be able to be advertised as being “organic” and flaunt a production method that is essentially biological and natural.
| Number | Date | Country | Kind |
|---|---|---|---|
| 06015659.3 | Jul 2006 | EP | regional |
