Happy Tuesday, everyone, 🍇

We start off in this new week by talking about a topic that is really close to our hearts and that is the basis of our philosophy as a winery producing organic wines:

Spontaneous fermentations.

“The unique and inimitable way for wines to fully express themselves while respecting our terroir.
When we talk about natural wines, the first thing that logically comes to mind is the spontaneity of the process of making a wine. Few human inputs, abolished use of chemistry, little (or no) addition of sulfites, and then, of course: only spontaneous fermentations.
Let us dwell on this term for a moment, and ask what spontaneous fermentation of a wine actually is. Does it mean that no selected yeasts are added? Yes, even.
So let us delve together into the wide world of spontaneous fermentation of natural wines, step by step.”

Alcoholic fermentation

“Let’s start at the beginning: if we had to explain what wine is, we would say that it is fermented grape juice. Grapes, in fact, once harvested and transported to the winery, can undergo destemming and crushing, until we obtain a juice, without or laden with marc with or without stems, called must. Once the must is obtained, however, it needs to be turned into wine. How does this happen? Through a particular family of single-celled fungi, yeasts. Yeasts are microorganisms that take part, or rather: enable the alcoholic fermentation phase. Thanks to the enzymes produced by the yeasts Saccharomyces cerevisiae — the famous “brewer’s yeast” — found on the skins of grapes, the yeast breaks down the complex sugars in the grapes, and then — in a second step — converts the simple sugars into ethyl alcohol.”

Yeasts in wine

Now, once we understand how the fermentation process occurs in grapes, we ask the first big question: where are the yeasts involved in alcoholic fermentation?
It seems obvious but it is not: in addition to the skins of the grapes, as mentioned above, the yeasts responsible for fermentation are found in the cellar. To be precise, in the barrels, between the walls of the tanks, on the walls, in the tanks… in short, in the whole environment around them. As a result, the cellar, as time passes, develops a true personal habitat, rich in different and unique yeasts. Thus, the so-called “biodiversity of the microbial crowd” allows a producer’s winemaking heritage to be enhanced as much as possible.

Selected yeasts

“At this point it comes naturally to ask: but if yeasts are everywhere-if indeed they surround us-so much so that some producers do not allow any outsiders to enter their cellars, otherwise they would risk “displacing” the potential of their own yeasts, why add them artificially? That the world is full of yeasts is an absolute and established truth. From here to say that it is easy to allow spontaneous fermentation, well, not really.
Conventional producers who choose to add selected yeasts to their wines do so primarily to make the fermentation process faster and easier. Adding yeast and bacterial cultures means in a very short time accumulating enough ethanol to cover the microbial species, in other words: the wines’ flavors are homogenized, not allowing them to express themselves in the time and manner that nature requires. Selected yeasts are identical to indigenous native yeasts in terms of genetics and metabolism, but their reproduction takes place in a controlled environment. They are “selected” because with their use there is no risk of damaging the quality of the wine. They are yeasts with excellent resistance to environmental conditions and that do not cause undesirable effects. They are inoculated at the fermentation stage and allow control of the entire process.”

Indigenous yeasts

“Are indigenous yeasts dangerous? Yes. Or rather, if you use only indigenous yeasts you run two main risks:
The timing: fermentation stops, does not start, or slows down
The results: the wine is likely to be defective due to abnormal fermentation
So yes, not adding yeast is a game few are willing to play. Producers who decide to let their fermentations occur spontaneously are those who deliberately decide to let the chemical process of turning sugars into alcohol happen naturally, without outside help. Thus, spontaneous fermentations are a difficult subject to work on, which only the most trained and studied winemakers can handle, with due care and attention.
Letting the indigenous yeasts work means conducting a fermentation that will naturally be able to slow down, stop and restart as summer temperatures rise, with the risk of affecting the final result. It means giving the wine the time it deserves, but also and above all allowing the full development of the organoleptic assets contained in a bottle and released the moment it is opened.”

The fine lees

“Once the life cycle is complete, the indigenous yeasts precipitate by autolysis, and what remains are the so-called “fine lees,” responsible for further increasing the complexity of a wine. Fine lees are those sediments formed at the end of alcoholic fermentation: in other words, they are the spent yeasts that, thanks to autolysis, release the aromatic substances that we perceive at the taste-olfactory level.
Selected yeasts, on the other hand, impoverish the wine because they homogenize its aromas and flavors, limiting the natural expression of a grape variety and terroir. Managing not to add selected yeasts, not to create the famous pied de cuve (the “starting foot,” i.e., a fermentation starter), and not to control temperatures during the fermentation phase, means knowing the world of wine”

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