This variety is typical for the western and central sections of Northern Bulgaria, mainly in the regions of Vidin, Pleven and Suhindol.
Gamza is a late ripening variety. It ripens during the second half of September. Windy hills with relatively rich soils and good exposure are the most suitable terrains for Gamza.
Wines produced from Gamza are harmonious, but to the sensitivity of the variety to climatic conditions it is not possible to achieve the desired quality every year from each region. Usually we make a slight correction of colour and acidity by adding other varieties – Cabernet, Merlot and Rubin. The pure Gamza wine is in strong demand on the markets in Germany and Russia. The Gamza variety is easily mixed with merlot. Our Merlot & Gamza wine is a bestseller on the British market.
This is a grape variety of Georgian origin. The areas under Rkatsiteli in Bulgaria are quite extensive. Rkatsiteli is a relatively late ripening variety – it ripens during the second half of September. It has a natural high yield. The variety is relative resistant against decay, draught and cold. Its is used to make white wines, sparkling wine and wine material for cognac-type beverages. Rkatsiteli does not have the potential for producing high-quality modern wines and for this reason its importance for wine production is diminishing.
The Muscat variety has a long history. It is considered as one of the first varieties, which have been described and defined. It bears different names in the different countries – Muscatto in Italy, Muscatel in Spain, and Muscat Otonel in Bulgaria. The name of the variety also has an ancient origin. It is considered that the name is related to the Latin word “musca” , which means “fly”. Flies are attracted by the sweet aroma of the ripe grape. Other researches link the name with “musk”.
Muscat is an early ripening wine and table variety. It ripens during the second half of August. It grows well on deep, light, humus-carbonate soils on hilly terrains. It is relatively resistant against draught, cold and decay.
Sauvignon Blanc originates from France. The variety is related to some of the most prestigious wines – Sanser and Poli Fume. The variety gained popularity during the 60-s of last century, when Robert Mondavi experimented with fermentation in barrels and launched the dry wines, thus creating a style of an exquisite fruitiness.
Sauvignon Blanc is planted on limited areas only in Bulgaria. Its is a medium ripening variety – the first half of September. Regions with humus-carbonate and gravel soils are considered as most suitable for Chardonnay. It has a high growth rate and high yield. It is susceptible to decay but is relative resistant against low temperatures.
Chardonnay is a grape variety widely associated with white wine. Its persistency against fashion trends among wine connoisseurs is amazing.
Chardonnay originates from Burgundy. For long years, the French were accustomed to giving names to wines according to their geographic appellation, while the importance of the variety remained underestimated. The emergence of trademark wines during the second half of the 20-th century reversed the trend in favour of Chardonnay. It easily emerged as a variety, which quickly gained recognition.
Chardonnay is an early ripening variety – it ripens in the end of August. Deeper, rich lime soils at the foot of hills are the most suitable terrains for Chardonnay. The variety is relatively resistant against draught and cold. It has a moderate growth rate, and assures and an average yield.
Some of the characteristics a used to describe the variety are green apple, peach, lemon, fig, pineapple, water melon, honey and nuts. Aging in oak barrels implants traces of oil, vanilla and smoke.
Process managers at Vinprom Rousse carefully monitor the quality of grape even while it is still on the vines. Thus they are capable of judging the quality of the raw material and identify which grape will be the most suitable for the types of wine on our assortment list. After the harvested raw material is delivered to the plant, it is subjected to analysis to determine the quantity of acids, its sanitary condition and the level of ripeness. Grape is fed to the grape mill, where it is processed in such a manner as to avoid breaking the seeds and the overly intensive contact of the must with the grape skins, which might result in an unwanted extraction of rough tannins. Tannins form the body and the structure of red wines; for white wines, however, this is an effect that has to be avoided, as these substances can easily replace the delicate taste and aroma. The grape pulp, which is obtained in this manner, is processed by two different methods, depending on the wine variety:
– Aromatic varieties like Muscat or Sauvignon Blanc are processed after some infusion in a vessel or in the wine press, in order to release more aromas, contained in the grape skin.
– Non-aromatic varieties like Chardonnay, Rikat and Dimyat, are not subjected to infusion and are directly transported to the pneumatic wine press, which is used to treat grape. Two fractions are obtained – free run and pressing (the so called musts), which are treated in a different way and are used to produce wine with different qualities. The wine, extracted from solid particles after alcoholic fermentation and before pressing, is called free run. The remaining solid particles are passed through a wine press, and the resulting wine is referred to as pressing. The substance remaining from the solid particles after pressing, is called mask and is used for fertilizing vineyards. Free run and pressing are stored separately.
Next follows a period of purification of must performed at a constant low temperature, in order to avoid the fermentation of natural yeast. This period is usually between 10 and 48 hours long.
Final adjustments of the must are made after decanting, and then a yeast culture is introduced in order to initiate the process of alcoholic fermentation.
Our wine making experts decide whether white must should be left to ferment in a stainless-steel vessel or in oak barrels, and this decision depends on their understanding about the style of wine they would like to obtain.
The wines, which have fermented in stainless-steel vessels, are clear and fresh. They fully manifest the qualities of the grape variety from a given terroir. On the other side, fermentation and aging sur lie in oak barrels aims at obtaining fullness, oiliness and complexity of wine and extraction of aromas from oak.
Usually wines are left to ferment until all the sugar is converted into alcohol or until the time, when the process manager decides to stop the process in order to preserve some of the sugar in the wine. We employ low fermentation temperatures which allows juices to slowly turn into wine. Thus we preserve the intensity of fruit and create a higher complexity.
The wine series produced at Vinprom Rousse – Chardonnay, Chardonnay Reserve, and Chardonnay Limited Selection are subjected to a specific type of fermentation, during which carboxylic acid is converted into lactic acid. this process is performed by lactobacterias and is called lactic fermentation. Lactic acid is less sharp than carboxylic acid, and the wine becomes softer and more exquisite at the end of the process.
Lactic fermentation for producing the variety Chardonnay of Vinprom Rousse is performed in stainless-steel vessels under a constant technological control. The two other lines – Reserve and Limited Selection – employs fermentation in small oak barrels made of Bulgarian, French and American oak.
The inside of the barrel is burned before starting the process. Burning is related to the technology used to make the barrels. Barrels may be slightly or deeply burned, and this defines the intensity and the nature of the aromas, which is transferred to wine.
Wines are left to age in barrels above the yeast sediment, set after fermentation. The French refer to this process as “sur lie”. With the advance of time, yeast cells start to disintegrate. Wood is a porous material and it allows some of the water and of the alcohol to evaporate during storage. This, in a natural way, we obtain a greater depth and intensity of the wine taste.
The grape varieties, used by Vinprom Rousse to produce its red wines, are Cabernet Sauvignon, Merlot, Gamza and Rubin (Ruby). Process managers, as in the case of white wines, monitor the quality of grape while it is still on the vine and determine what type of wine will be produced out of each grape variety. After the grape is subjected to measurements and appraisal, it is poured into the grape mill, where the stems are removed and the skin is slightly cracked. This allows grape juice to immediately enter in contact with the skin, from which is absorbs pigments, tannins and aromas.
Yeast is added after milling. The fermentation starts and is performed in stainless-steel vessels, which allows to secure a sterile and easily controllable environment that does not affect wine.
During fermentation, process managers at Vinprom Rousse monitor the extraction of colour and tannin from the skins, and the changes in taste. The skins are removed after the wine attains its optimal character.
At Vinprom Rousse, lactic fermentation is performed in vessels, which allow for the highest level of process control. After that wines are left to age sur lie – in barrels or in the same vessels as before. Just like in white wine, the dissolution of yeast during aging contributes to raising the intensity and depth of wine taste.
The influence of oak on wine aging is determined by four main factors: type of oak, drying and seasoning, manner and level of burning applied while the barrel is being made.
The process of burning is the most important factor that influences the change in the nature of oak. At the same time this is the main factor that defines wine aromas. Let us have a closer look at some of these factors:
Type of oak, forests and terroir
Oak differs in character when cut in different forests and regions. The main factor underlying these differences is the soil humidity, as it determines the rate of growth of the tree, and thus – its structure. Forests growing more slowly are a source of oak with a finer structure. This influences the tannin and vanillin contents and their transfer during aging wine in oak barrels. The aroma, the age and the height of the tree are also very important. Substantial differences are often found in the structure of the wood at the tree peak and at its base. Coopers pay attention also to the type and the width of the annual circles as well as to the radial beams from the core of the trunk outwards to its bark. All these fact provide information about the quantity of vanillin and tannin.
The terroir and the type of oak determine the tannin contents. Usually, French oak has more tannins. The American oak, Quercus alba, is used exclusively for wine barrels; the largest clusters of this type of oak are found in the State of Missouri. European oak, used by most of the coopers on both sides of the Atlantic, is represented by two species – Quercus robur and Quercus petraea. The production of wine barrels out of Russian oak has been on the rise for several years. Russia has the largest natural oak forests in the world and hence the price of Russian oak is lower.
The southern section of the Balkan mountain is a relatively large source of Quercus petraea. According to studies, oak in Bulgaria is close in properties to the French oak and, similarly, it is characterized by a high tannins content. The US World Cooperage is one of the large wine barrel producers in the world to pioneer the promotion of the Bulgarian oak and has launched a project to impose the so called Balkan oak on the market.
Drying and seasoning
Wood start drying immediately after it is cut. It may be left lying for several months at the place it was cut before delivered to a timber plant. This is referred to as the initial stage of storage. At first cut, half of the mass of oak comes from moisture, which is reduced by some 20 percent within the first three months. Wood trunks are hydroscopic – moisture contents increases in winter and falls in summer.
Seasoning is the next phase. Some volatile substances are evaporated, and others are oxidized while the oak is drying. As a result of a specific microbiological activity, various substances are formed or disintegrate. These changes depend on the conditions, under which the oak is left to dry. Mould and various type of fungi may develop on the surface in a moist environment. Oak, which has been stored in the open, may irreversibly lose some of its valuable components. It is considered that extended seasoning softens the character of the barrel made out of this type of oak.
The traditional method is related to the use of open fire from wood blocks. Coopers monitor the process of burning by the scents, which are emitted by the burnt arcs in order to determine the desired degree of burning.
There are also more modern methods, in which the temperature of the barrel and the time of burning is monitored by computers. Various aromas are formed after the barrel is heated to a certain temperature during burning, as the heat, when penetrating the wood, releases components located at various depths inside the material.
Studies have revealed that the tannins are the substances, which are the most sensitive to heating and are easily decomposed. With the increase of temperature sugars start to caramelize and the oak aroma is transformed into a sweet scent of spices. Next follows the disintegration of lignin, which results in the appearance of a vanilla aroma. The rich aromas of almond, chocolate, coffee, and the so-called “smoke” aromas are generated at higher temperatures and degrees of burning.
While most of the white wines are suitable for consumption within a two or three years after harvesting the grape, many red wines preserve their qualities – and even improve them – with age.
Why do red wines improve their quality with age?
Everything depends on the tannins. The tannins are the astringent and bitter group of substances, which are found in the seeds and in the skin of the grape. In addition to the fact that these substances transfer a pleasant tartness to wine, tannins provide for a higher aging potential of the wine by slowing down oxidation.
The extraction of tanning is an important stage of making red wine. Unlike the must for white wines, which is pressed out from grape before fermentation, red wine is left to ferment inside the skin, even with whole intact berries. Winemakers monitor tannin extraction during fermentation by manipulating the grape skins.
Tannins are bitter in a young wine. With time, tannin compounds react and together with pigment molecules form long polymer chains. When these polymers become long enough, they settle, thus making wine more pleasantly astringent rather than bitter. This process starts during infusion and fermentation and continues after the wine is bottled.
Wine is much less exposed to oxygen when bottled. This slows down transformations. While the various components, related to the taste of wine, interact among themselves and with the substances acquired from the oak during fermentation and aging in barrels, and while tannins and pigments continue to link, with time the wine changes its colour from purple to brick-red and develops various tastes and aromas.
The cork closing the bottle is of a major importance fro the quality aging of wine. That is why wines with a potential for aging are always bottled with corks of established quality.
Wine may be preserved during aging only if it is bottled with a high-quality cork. Cork plugs, regardless of their quality, as well as the cheap agglomerates made out of glued cork shavings, may release an unpleasant cork side taste in the wine. A cork, which has been in contact with mould, develops a repulsive musty smell. Cork producers spare no efforts in improving the technology for cork production.
Many winemakers rely on alternative types of corks. Synthetic corks are quite popular, especially with winemakers from the New World countries. They still allow to preserve the ritual of removing the cork, which is valuable phase for many wine connoisseurs, at the same time eliminating the risk to encounter a “corked” wine.
Most of the wines produced by Vinprom Rousse are bottled with synthetic corks, and the tendency is to increase the share of this material.
Before we decided to introduce synthetic corks, we made a series of tests. We analyzed the chemical and organoleptic characteristics of wine, the response of various types of corks to extreme temperatures and their qualities as a barrier between wine and air.