The fine wines of the Langhe > Modern method of production

Each wine has a peculiar color, which goes from white to yellow-greenish, rosé, red, dark purple; both the aroma and fragrance, which determine the so called “bouquet”, the taste and the corpus, are peculiar too. The product classification considers several factors such as the taste, alcoholic content, the harvest and vinification year, the original vine, the ground and climate where the vineyard was cultivated (i.e. calcareous grounds give out high alcoholic content wines; volcanic grounds give out “corpus” wines; siliceous grounds give out delicate wines). It is important for the vinification the grape ripening index; super-ripen grapes have minor acidity but higher sugar content; so that they can be utilized to obtain “passito” wine [a wine obtained from died grapes]. White or red table wines are obtained from medium alcoholic content grapes (9-10%); these wine can be aged, obtaining superior wines, with a higher alcoholic content. Blending wines, which are utilized to mix more precious but less robust wines (or for peculiar manufactures) can be obtained from grapes rich of color, alcohol and extracts. Some rather aromatic and scented grapes are utilized to produce dessert wines, while others (essentially white) for the preparation of natural sparkling wines. The first operation of the wine production cycle is the pressing, which is carried out industrially by pressing machines; wine presses are utilized for white-vinified grapes. The final product of the pressing is the must, which is put in accurately cleaned tubs and, if necessary, its chemical composition is corrected (sugar, acidity, color and extracts) in order to obtain a better result. The employment of sulphurous dioxide is an enological practice very much spread: just after the pressing it is carried out the sulphurization (with diverse doses, between 5 and 20 g ql, according to the quality, sugar content, and sanitary status of the grapes) through the employment of gaseous sulphurous dioxide in cylinders or as potassium bisulphite. Adding sulphurous dioxide to the must allows to block the activity of the naturally-present yeasts, so that the undesirable flora is eliminated, and the fermentation is carried out correctly with the employment of selected yeasts; it eliminates “wild” yeasts, in favour of the elliptic ones, more resistant and suitable for a balanced fermentation; it facilitates a first defecation by causing the precipitation of the colloidal substances, which otherwise would make turbid the must; it solubilizes the colouring substances which are located in the grape peel, and functions as anti-oxidant for the must. The second phase consists of vinification, which is the alcoholic fermentation of the must in open vats. When the must is separated from grape peels and stalks (so that only the juice is fermenting) it takes places the vinification into white wine, which means that white wine is obtained from black grapes. Instead, the vinification into red wine occurs when the must is fermented together with the marc: during the fermentation into red wine, the “cappello [hat]” is formed, which consists of the grape peels and stalks gathering on the surface, so that millings are necessary, which are re-mixings which avoid the “cappello” acetification and facilitate the airing of the must. Millings are not necessary if the fermentation is carried out with a hole diaphragm which keeps the “cappello” immerged into vats, and a system of re-assembling pumps the must to surface. Vats, where the must circulates automatically, due to the flow which takes place internally (due to the lightness of the hydro-alcoholic liquid which is formed), are very much utilized. Between these vats, the best are the so-called “amphora-vats”, which consists of two parts which communicate by a wood pipe and a narrow open with a grill, with a hole in its inferior part. In these vats, the carbon dioxide pushes the “cappello” toward the grating, which keeps it immerged and impedes the flowing of the must which, due to the gas pressure which is formed during fermenting, is pushed through the wood pipe to the superior part of the vat, so that a continuous movement is given to the liquid. For the vinification into white wine, millings are not necessary, and the airing is obtained by insufflating air into the vat. The vinification lasts between 24 hours and a week, according to the quality of the wine, which is being produced, and the local climate. A warm climate accelerates the alcoholic fermentation, which is caused by the yeasts contained in grape peels; fermentation variations are caused by adding to the must specific yeasts, which are selected so that grapes can develop their characteristic taste and bouquet. During vinification various intermediate products are obtained, such as: glycerine, acetic acid, acetyl-methyl-carbinol and lactic acid, which are due to the fermentation of the sugar, superior alcohols which are due to the blastomycetyc fermentation of amino acids, succinic acid which derives from sugars and glutamic acid, and methyl alcohol which is due to peptic substances. Vinification is followed by the drawing off, which is the separation of the must from the marc, which can be anticipated or delayed, according to the quality of grapes; the marc from the vinification into red wine is employed, after the pressing, as feed and for the production of alcohol, tartaric acid, vinegar, light wines, second wines, grappa; the marc from the vinification into white wine (virgin marc) are pressed in order to obtain pressed wine: the wine obtained from the first pressing is added to the “vinofiore”, while the one which derives from the other pressings is utilized with not precious but high alcoholic-contented wines. The wine, which is obtained from the drawing off, sometimes needs a correction of its alcoholic content, acidity or color, or an improvement of its organoleptic characteristics: which can be obtained by blending, re-fermenting in case of fresh marc which has not been pressed, or concentrating. The wine blending is the most common practice, and it is carried out by mixing opportune percentages of blending wines, or correcting the must which lacks of sugar, by adding concentrated must; in order to dilute the must which is rich of sugar, it is necessary adding acidulate water with tartaric acid. The scarce acidity of the must is corrected by blending with higher acidity must, or by adding tartaric or citric acid (0,1%). An increment of the acidity is obtained also by sulphuring, which means adding calcium sulphate (0,1%). The decrement of acidity is obtained by directly neutralizing and adding calcium or potassium carbonate. The color is corrected variously: by adding enocyanine or the boiling product of the must (with grape peels and stalks), or limiting to the minimum the millings. The wine which is broached from a vat is placed into barrels or impermeable concrete cisterns, which are kept at the temperature of 15°C, where the secondary alcoholic fermentation takes place: during this phase it occurs the transformation of the residual sugar and a loss of volume which, in order not to alter the wine, is treated with filling the barrels with the same quality wine. Then the wine goes through regular decanting in order to separate it from the deposit formed in the bottom of barrels or cisterns (sediment). It is so realized the ageing of the wine, which can last for months or years, according to the wine quality. The wine, before being marketed, is filtered and clarified; in order to preserve less precious blending wines, sterilization is used, through 65° pasteurization (for 15 minutes) or through 75° stassanization (for 20-60 seconds); finally, the wine is subjected to a prolonged refrigeration (1-2°C) and a new low temperature filtering. The wine is then bottled in sterile bottles, which are sealed by sterile crown caps or corks. A label is attached on the bottles, where it has to be indicated the alcoholic content and, for DOC productions, the year, the serial number and the copyright. The wine is a product which is often subjected to sophistications and frauds, so that it is periodically controlled by the food police, in order to verify that its content correspond to the wine quality declared on the label and regulated by law. The wine is subjected to several physical, chemical, and microbial alterations, which are frequent especially if, during the diverse production phases, the most suitable rules (as far as hygiene and enological rules are concerned) are not observed. Chemical-physical common anomalies are due to the precipitation of iron and copper compounds, which can make the wine turbid and can alter its colour: iron and copper ions in the wine, together with other elements – tannin compounds, temperature, pII, etc – facilitates the formation of insoluble complexes, which negatively influence its preservation. Microbial alterations are even more frequent, which especially consist of: flowers of wine, which is due to Candida yeasts (recognizable from the subtle whitish veil which changes rapidly into a thicker and wrinkled membrane. The wines attached – often lacking of acidity – shows modifications in its composition: their total acidity and alcoholic content decrease, while their acetic aldehyde tenor increases. Nowadays, the employment of modern iron (or covered with resins) containers, and the employment of pasteurization, allow to reduce to the minimum the pollution which is caused by flowers of the wine; sourness and acescence; the agents responsible (belonging to the Acetobacter genre) cause the oxidation of the ethyl alcohol and acetic acid which, if present in abnormal doses, gives wine a characteristic and unpleasant aroma. A right employment of sulphurous dioxide and the observation of some hygiene rules during vinification, allow avoiding the presence of acetic bacteria, which are difficultly eliminable once attacked the wine. Other microbial alterations, which are caused by lactic bacteria, are the “girato” and sourness, both less spread nowadays thank to a more rational employment of sulphurization.