CellarTV in brief: About Winemaking

Tradition meets technology:
A basketpress at Robert Mondavi Winery, Napa Valley, CA

About Winemaking

Winemaking per se is easy; you can do it at home.
The process involves harvesting of grapes, putting them into a container, crushing them a little bit and let them ferment. After fermentation is completed separate the solid substances from the liquid ones, and there you go, you have wine.

If it would be that easy …
Making high-quality wine takes a lot of effort in the vineyard and in the winery.

Starting in the vineyard, we should consider the origin of the grapes and vines. As you might imagine, within the last decades of wine cultivation the grape variety developed several mutations, called clones.
Particular varietals and clones grow best in particular areas.
The physical characteristics of these areas, as soil structure, permeability, profundity, soil-type etc., influence the quality of the wine. Generally, the best soil is the one letting the grape ripen consistent. Warm soil in cool climates is good and cool soil in warm climates. Very important for good soil is to be profound, because with acute dryness the vine closes its pores and photosynthesis is disabled.
Sustained influence on wine quality is also given by the microclimate including incident solar irradiation, wind, altitude, slope growing, frost and gravitation erosion.
In these days vines are mostly “educated”. As they were standing in single bushes back then, vines now are educated in clear rows, by cutting and bending them over wires. This makes it easier to harvest grapes (automatically) and gives perfect sun exposure.

There are different methods in cultivating wine, most common the conventional way, the organic way and the biodynamic method. Organic cultivation of wine excludes the use of chemical fertilizer, insecticides, herbicides or other chemicals. Biodynamic winegrowing is even more strict and follows the fundamentals of Rudolf Steiner. This involves for example distinct workflows are only performed during distinct phases of the moon, the use of different herbs within the vineyard and, very importantly, the compost, which is also exclusively “grown” with special treatments. Beyond all questions the soil is enriched with microbial live.

Now that we have taken care of carefully growing our special grapes on our individual soil in a very particular microclimate with extraordinary treatment, we are ready to harvest.
More quantity is less quality! Limitation of the yields during the growing period is not only defined by law in Europe, but also increases the quality of the grapes, thus the wine.
The most important decision is when to harvest the grapes. This is fulfilled with the content of sugar and acidity in the grape. During maturation the content of sugar increases and acidity decreases. For each kind of wine there is a special time point to harvest. Highest quality can be achieved by hand picking, because impurities as with leaves, rocks or soil as well as rotten grapes or grapes with fungi can be avoided.
The first step in wine production includes the use of sulfur oxide (SO2); little doses are given to mash or to must. There it serves as an antiseptic and keeps the wine from oxidation.
Further steps can be performed depending on numerous things, including type of wine, tradition, climate, winemakers taste and opinion and many many more and can vary in each step.
Red wines drive their color from the grape skins, thus after destemming and crushing, juice and skins will be in contact during fermentation. Most white wines are made without destemming or crushing and are brought from picking bins directly to the press.
Fermentation barrels made of oak are rarely used nowadays, because they are not as easy to clean and disinfect as cement basins or steel tanks. Every vineyard and vinery has its own yeasts all over. It is up the winemaker to use external cultured yeasts or let the fermentation go its own vineyard specific way. During fermentation yeast cells feed on the sugars in the must and multiply, producing carbon dioxide gas and alcohol. The fermentation temperature influences the wine quality as well, red wines need a temperature between 22 and 25°C and white wines 15 to 18°C. A rule of thumb says that for every gram of sugar converted, half a gram of alcohol is created.
Different methods of pressing the mash are used, where as the basked press is used for more patient winemakers, the screw press is used for mass production.
Secondary fermentation takes place in steel tanks or oak barrels, depending on the wine and winemaker. During this slower second fermentation and aging process the wine is usually kept under airlock to protect the wine from oxidation. This so called malolactic fermentation takes place when lactic acid bacteria metabolize malic acid and produce lactic acid and carbon dioxide. High levels of malic acid cause a harsh and bitter taste whereas lactic acid is tenderer and less sour.
Also dependent on the winemaker´s taste and style is, if the wine is blended or will be homogeneous wine. Blending can occur within the fields, where you have different types of vines in one vineyard, harvesting can take place at the same time or at different time points. Field comprehensive blending includes a variety of grapes from different fields either fermented together or separately. So, blending can take place in every step of the wine making process, there are no rules.
After a certain time in barrels or steel tanks the wine can be bottled and, depending on the quality and varietal, it can be cellared for several years.


Barrel storing at Kalleske, Barossa Valley, AUS