1. Introduction: a new generation of yeasts for emerging oenological needs
Innovation in oenological microbiology has always been a driving force for evolution in the wine sector. This is the context for the new ‘SELEZIONE’ range of EVER yeasts, launched in 2024, which offers strains selected for specific, modern purposes, designed to respond to concrete challenges such as energy saving, sulphite reduction and enhancement of the aromatic profile.
The design of this range is part of a broader interdisciplinary approach called “YTEAM” (Yeast – Total Enhancement Advanced Method), which involves Research & Development department with the support and supervision of Italiana Biotecnologie.
The YTEAM method is an integrated approach that encompasses all stages of the process: from strain selection to genomic characterisation, from controlled multiplication to industrial production, to genetic, microbiological and quality controls, without neglecting tailor-made technical support for application in the winery.
This model, which values constant dialogue between scientific research and winemaking practice, has made it possible to develop yeasts capable of combining technical performance, sustainability and sensory quality.
The first two representatives of the SELEZIONE range, R.E. 515 and L.S. 502, have been developed and tested under a wide range of operating conditions to evaluate their performance and qualitative contribution to wines.
2. SELEZIONE R.E. 515 yeast – Optimised energy, preserved quality
R.E. 515 yeast was selected with the aim of reducing energy consumption in the winery. Its distinctive feature is its ability to conduct regular fermentations even at higher than standard temperatures (above 20-22 °C) without compromising the aromatic quality of the final product: the wine obtained at low temperatures is comparable in aromatic profile to that obtained at temperatures above 20 °C. This characteristic allows for significant energy savings by reducing the need for cooling.
Main characteristics:
- Excellent resistance to high temperatures: performs well even at temperatures above 20–22 °C.
- Fast and regular kinetics: maintains constant fermentation even in critical thermal conditions.
- Clean aromatic profile: it imparts notes of ripe fruit with excellent expression of acetates and ethyl esters and is little affected by fermentation temperature.
- Sustainable management: it promotes fermentation with reduced energy impact thanks to the lower use of refrigeration systems.
In all cases, the total acidity is consistent with the initial data for the must (7.1 g/l).
In all cases where temperatures were compared, the total acidity was higher at higher temperatures.
The exception was the case with inorganic nutrition at 23°C. This result will require verification in the near future.
3. Yeast L.S. 502 – Fermentation with low sulphur dioxide (and acetaldehyde) production
The yeast L.S. 502 was developed to address one of the major challenges in contemporary winemaking: reducing SO₂ and acetaldehyde levels in the finished wine. This strain was selected for its low tendency to produce acetaldehyde during fermentation, allowing for very low sulphur dioxide production while still ensuring protection and stability for the wine. This yeast also stands out for its ability to maintain higher total acidity than others, while keeping volatile acidity to a minimum. Its fermentation kinetics are regular and in line with other yeasts for primary fermentation, without showing any particularities in terms of performance. Strenghts:- Low production of acetaldehyde and sulphur dioxide: significantly reduces the total sulphur dioxide concentration in the finished wine.
- Better oxidative control: allows for more stable and clean wines.
- Ideal for low sulphite production: perfectly meets market demands for wines with less sulphites.
- Elegant sensory profile: enhances the fruity and varietal components, particularly in young white and rosé wines.
In this test (ref. graph no. 6), the analytical profiles of microfermentations under controlled conditions of historical EVER strains were compared with L.S.502, confirming that the latter has a good alcohol tolerance, capable of significantly limiting the production of volatile acidity and sulphur dioxide. It is a medium producer of glycerol.
Graphs 7 and 8 show the comparative performance test of L.S. 502 on the same must base but with different nutrients and comparing two different temperatures: 14°C vs 20°C.
It can be seen that in the basic analysis of graph 7, temperature significantly influences glycerol production and slightly influences sulphur dioxide production. In terms of aromatic profiles, it is confirmed that the higher temperature leads to the production of a higher content of higher alcohols, but the lower temperature allows for the maximum expression of citrus and fresh orange blossom notes, which are extremely valuable for fresh and modern wines.
Nutrition with Creaferm GSH and Creaferm Fruit further emphasises these notes, as evidenced by the higher production of total terpenoids.
4. Trial studies: tests on varieties, conditions and styles
Both strains were tested in microvinification and full-scale trials on aromatic and neutral varieties (such as Chardonnay, Pinot Grigio, Sangiovese and Nero d’Avola) and under extreme conditions in terms of temperature and nutrients.
Even in unconventional applications, such as refermentation, and although not designed for this purpose, R.E. 515 and L.S. 502 showed reliable kinetics in this context as well, demonstrating great versatility.
Analysis of the data collected shows consistency in the results, in particular:
- for R.E. 515, tolerance to high temperatures allowed regular fermentation to be carried out even beyond conventional temperatures, which normally do not exceed 20°C, up to 26–28°C, significantly reducing the use of refrigeration systems and generating concrete benefits in terms of energy efficiency (with estimated savings of between 20 and 30%).
- for L.S. 502, significant tests were conducted comparing fermentations at 20°C and 14°C. In both conditions, the results showed excellent control of total SO₂, acetaldehyde production and volatile acidity. Gas chromatography analysis also showed that combining L.S. 502 with specific nutrients leads to higher levels of esters, acetates and excellent terpene evolution, key compounds for fruity and floral notes.
5. Sensory profile: two approaches, two aromatic identities
From a sensory point of view, the two strains offer different and complementary experiences:
- R.E. 515 tends to express a “clean” and rounded fermentation profile, with notes of ripe fruit and softness on the palate. At high temperatures, even up to 35°C, hints of acetates such as ripe peach emerge without any noticeable alteration of the aromatic profiles.
- L.S. 502 presents fresher, more subtle and citrusy notes such as cedar, grapefruit and lemon, with greater definition of varietal characteristics and a more vertical taste sensation. At low temperatures, it expresses hints of grapefruit, bergamot, lime and tropical fruit, while at higher temperatures it veers towards notes of pear and peach. The wines are distinguished by their finesse, freshness and length on the palate.
6. Conclusions: a SELECTION at the service of the modern winemaker
The yeasts in the ‘SELEZIONE’ range represent a step towards a new concept of primary fermentation: no longer a neutral process, but a precision winemaking tool.
The technical characteristics of the two yeasts clearly define their scope of use:
- R.E. 515 is the ideal yeast for those who want to optimise energy management in the cellar without compromising on aromatic quality. It is suitable for fermentation at high temperatures (even 26 °C), with estimated energy savings of between 20 and 30%, maintaining a clean fermentation profile and good fruit expression.
- L.S. 502 is aimed at those seeking more sustainable sulphur management, thanks to its low acetaldehyde production and ability to maintain high total acidity with minimal volatility. The wines are cleaner, more stable and characterised by aromatic freshness and varietal definition.
Both strains have proven reliable even in critical conditions (high temperature, low nutrients, refermentations) and contribute to more sustainable, effective and targeted wine production. Validated on a real scale, R.E. 515 and L.S. 502 are two concrete allies for winemakers who wish to combine technical efficiency with more precise control of the aromatic profile, stability and freshness of the wine.
