Wine technology and climatic effects
Although winemaking sounds romantic to wine drinkers, it's an economic issue for most winemakers. From that perspective it's interesting to see what's really important in making a good wine. First of all, quality of wine depends on a complexity of factors:
- Amount of UV light absorbed during the growth stage of the grapes. This is quite short.
- Average warmth during this period of time.
- Amount of UV light absorbed during that time of the year, so that chlorophyl is still present in the green leaves and bunches still hang down from the branches.
- Stress factors during the year like: drought, root dying because of initially high ground water levels followed by an extremely long, hot period. Leaf damage due to hail, glutton, wrong pruning of bushes. Lack of minerals and trace elements during the short period of growth.
- Strikes of moulds on both leaves and bunches.
- And last but not least the amount of UV-light absorbed during the last weeks before harvesting. Especially in this period most of the sugars are stored in the bunches and acids are degraded. If UV rays are able to reach the grapes themselves than malic acid is converted into tartaric acid leading to a flavorish, rich wine. This process is very important and requires removal of old and dead leaves from the bunches in time. Grapes hanging in the top of the vines are of the least quality. Therefore, we remove all those grapes a few weeks prior to harvesting.
Not the sun only
Wine quality not only depends on heat. For instance wine cannot be made from wine originating from green houses as glass absorbs almost all UV light. It's the total sum and alterations of rain, ground water level, sunny spells, sunshine, drought, wind and a clear sky. Everything should take place at the right time so as to end up with leaf-rich bushes. Influencing grape growth, formation of sugars and avoiding growth of moulds. Also the direction of plant paths and the distances between the individual plants are important. Finally, soil quality plays an important role, but not in a way everybody thinks.
Marius explanes: “Strangely, everybody talks a lot about soil quality as being the most important issue for winemaking”. But in the “books” I can’t find much proof for that. In fact, vines need to live and grow. Therefore a fertile soil, providing minerals and water, is necessary.
Finally our grapes have a sugar content of approximately 20%. After fermentation and storage this amount is converted into alcohol and carbon dioxide.
Rain on time
Climate and soil conditions are very special in Made. Due to the presence of enormous fresh water basins in the immediate neighborhood the amount of rain is slightly less compared to areas a few kilometres further. Also the soil is rather poor, acidic and porous as the main component is ferruginous sand. This resembles vineyard conditions from southern countries quite well, leaving the advantage of plenty of rain during the growth period and less rain in the sugar forming period. The one and only disadvantage is the amount of solar heat, which is less.
In fact, there are two disadvantages to growing grapes in The Netherlands. First of all, the climate can be cold in spring, when night-frost can damage blossoms and buds. To prevent this the vineyard is sprayed with water so it can resist temperatures down to –8°C (18 F). The other one is the lower altitude of the sun. We compensate for that by allowing the vines to grow up to 2.5 meter leaving the first meter open. Also we plant vines in rows with a row distance of at least 2 meters. This enables individual grapes to catch as much sun as possible.
Cold when harvesting
Other very important features are the temperature at which grapes are harvested and stored prior to crunching. Marius says: “In Made we only harvest in the morning when it’s cold. We immediately drop the grapes in large containers and have them settle for a couple of hours. The low temperature prevents inoculation by unwanted bacteria and enzymes. After crunching we allow the juice to settle for a few hours. Any lees are than separated and the juice will undergo its first fermentation under controlled conditions.” He ended by saying: “Temperature plays a significant role. In Australia I even saw midnight harvesting!”
According to Marius the following items play a prominent role in winemaking (in decreasing order of importance):
- Grape varieties
- Pruning; both at the start of the season and as shortly as possible before harvesting
- Plant direction of vines toward sun and wind
- Timely removal of dead leaves