Many times we hear that a wine is made with “the least possible intervention”. We hear this saying from some producers and also from some fans or wine lovers when they complain that their wine has “a lot of intervention.” What is this “intervention” thing anyway? Sometimes it seems to be a great unknown.

First of all, we must start from the basic concept that wine is a drink made by human beings. Without intervention of whoever is making the wine, there is no wine. Nature does not make wine, Nature makes grapes. This means that the wine needs the intervention of a person to exist. Once this is laid down, we can talk about so many things. Since there are many aspects in which a person can intervene when making wine, today we will only talk about a couple of them because otherwise this conversation would take a long time. Though surely we will talk about more than two topics. There is a lot of ways we can intervene in the wine.

We already talked about the use of wood, and that is an aspect in which the intervention can be absolute, to the point of completely changing a wine. To begin with, it is not the same using French, American, Slavonian or Hungarian oak, to name a few. As for oak of French origin, for example, there are several forests where different styles of oak come from producing different styles of barrel. You can also use chestnut or acacia wood. The latter, for example, is a very neutral wood that has no contribution to wine, especially if not toasted. Speaking of toasting the barrel, there are different types of toast levels and the higher the level of toasting the more aggressive the final result will be.

The container we will use for wine aging also has a great influence. There is big difference between a traditional 225-liter barrel and a 2,000-liter barrel. In many cases we see that different regions favor a type of barrel. It is rare to find non 225-liter barrels in Rioja or Ribera del Duero, and it is rare to find this same type of barrel in Barolo or Valpolicella in Italy, where the common practice is using barrels of 10, 20 or 30 hectoliters.

The influence of the vintages a barrel has been used, as in the previous case, is accentuated with its capacity. A first-year-of-use 225-liter barrel has a radically different contribution than the same barrel five vintages down the road. Moreover, it also influences the level of toasting, whether it is light, medium or high.

In each of these cases, and mixing every possibility, the outcome will be completely different and the difference will come from the choice we make in each of those aspects.

Another issue we can discuss is the use of autochthonous yeasts or selected yeasts. This is an area in which intervention on wine has a tremendous influence. Yeasts are microorganisms living on the skin of the grape and when they are mixed with the must, they feed on the sugar it contains. The result of this action is the transformation of said sugar into alcohol and a clear contribution to the flavor that the resulting wine will have. This process is called alcoholic fermentation and usually starts when there is a small amount of must and its temperature favors the beginning of this process. The winemaker can intervene in this by modifying the temperature of the must. Raising the temperature favors the beginning of the fermentation and lowering the temperature slows it down, stops it or even prevents it to start.

The autochthonous yeasts are those living in the grape skin and in the vineyard from which they come and that we can also find them living in the winery and in the equipment used to work with the grapes. We might say they are the best yeasts to make the fermentation because they are the ones belonging to the grape and the vineyard, though it is true that in the vineyard we can also find yeasts that are not always suitable for our wine. Many producers, especially those who work in organic, biodynamic and/or natural principles, prefer to use the autochthonous yeasts (also called native or wild yeasts) because they are going to endow the wine with the particularities of the variety, vineyard, etc.

Normally, a small cellar or a cellar with a limited production works with the autochthonous yeasts, which in general are the ones that give the wine its character, as we have seen above. A bigger winery, or a winery holding different plots distributed over the area and not necessarily adjacent one to the other, will otherwise work differently to the first one. It is possible that the winemaker prefers the yeasts of one of the plots, or that he simply prefers to use a yeast created in a laboratory that better adapts to the style he is looking for and that homogenizes the final wine. The first case, the one of the small winery, is about employing autochthonous yeasts for the alcoholic fermentation, which is also called spontaneous. The case of the large winery is the example of selected yeasts that, when poured into the must deposit, start the alcoholic fermentation in a process known as inoculated fermentation. In this case, the final result will be the one that this selected yeast, which has been created in a laboratory, exercises on the wine.

It may seem a bit strange, that a laboratory yeast can change a wine, but as for everything in this life, what is written is proof of everything and when laboratories sell their products, they indicate the benefits of each yeast in their catalogs. As an example, there is a laboratory yeast whose name is BM45 and whose influence in wine is “contributing to greater acidity, less astringency and better body in the mouth. It brings aromas of jams, rose petals and liqueur cherry, with notes of sweet spices, licorice and cedar.” According to this laboratory, this yeast is “indicated for the Sangiovese grape and is perfect for creating wines with a traditional Italian style.” As we can see, a perfect tasting note of a wine made only on what the used yeast provides and not what we find in the vineyard.

I think that after reading this description we can realize that by using a particular yeast we are exercising such an intervention on the wine that there was nothing left of what was originally in the vineyard. We can also see why there are so many cold climates that offer white wines with aromas of tropical fruits.

Another day we will talk about how we can intervene in wine through our actions in the vineyard, for today is already late.