Friday, August 27 2010 11:59

Indigenous yeasts from Chardonnay grapes
This is a very important harvest for us: we have started to select and reproduce indigenous yeasts from every vineyard in Tenuta Belicello.
After a few years of experience, this decision has become a logical consequence of our commitment to quality and to a more sustainable grape growing and winemaking.
As a matter of fact, the yeasts play a very important role in defining the aromatic profile of the wines and they are able to outline their personality and character. Different yeasts have differing physiological and fermentative properties, therefore the actual strain of yeast used in the winemaking has a direct impact on the finished wine.
We expect at least two results from our choice of using indigenous yeasts for our fermentations: first of all, we are well aware that wines made with "wild" strains could be less manageable than those made with selected ones. At the same time, we believe that what is expected to be an issue would, on the contrary, lead to a more original, probably unconventional character of the wines that we are going to make this year.
It is a difficult path, but we think it’s worth it!
How we obtained our yeasts?
Yeasts are micro-organisms naturally present on the grapes’ skin, which are responsible of the wine’s fermentation: the strain composition, its quality and characteristics are deeply influenced by the natural environment, the so-called terroir.
Pre-requisites to reproduce strong yeasts that should be able to bring the fermentation to its very end are a clean environment and a great integrity and quality of the grapes, both from a chemical and organoleptic point of view.
We started on July 26th to make our culture from Chardonnay grapes: 220 lbs of sound clusters, carefully selected and picked by hand in small baskets. After picking, they were immediately brought to the winery: high acidity, amazing aromas and good sugar level were the parameters we monitored to start our culture.
The grapes were crushed by hand in small stainless steel tanks. We used the whole cluster (stem, skins, seeds and juice) to obtain the maximum quantity of potential yeasts, and patiently waited for the yeasts to develop.
After 10 days, we obtained 100 gallons of fermenting must that we used to inoculate 9 tons of pre-dawn harvested Chardonnay grapes.
A part of the grapes was crio-macerated with the skins for 12 hours and then soft-pressed before inoculation (the one in tank), the other part was inoculated before the pressing (the one in barrels).
The results are excellent so far: the yeasts reproduced in both cases and developed a continuous fermentation. In the first case the fermentation has been slower: the yeasts consumed only 0.35 oz of sugars per day and they have worked for over 15 days. In the second case the must fermented only 11 days. In both situations we were surprised to have obtained a very low degree of volatile acidity, a low pH and an amazing level of total acidity. Which, translated into a spoken language, means fresh and fruity aromas, easy drinkable quality and a limited alcohol level (around 12.50).



