In wineries, the consumption of cooling energy has a significant impact on operating costs and environmental impact throughout the production chain. For this reason, professionals in the sector are constantly looking for innovative approaches to energy saving and low environmental impact. In parallel, the wine industry is increasingly moving towards sustainability-conscious production, in response to both growing consumer awareness and international guidelines.
In fact, the OIV 2020-2024 strategic plan emphasises the importance of reducing energy consumption also through microbiological innovation: ‘In wine production, it appears important to aim towards forms (…) of reducing energy consumption, making use of studies and results in the microbiological field (…).’
Within this context, the selection and use of specific yeasts can play a key role in optimising the fermentation process, helping to limit the need for cooling without compromising wine quality.
Based on these considerations, Ever’s team has developed strategies to make the oenological process more energy efficient and sustainable, while guaranteeing a quality product.
Summary Ever research
Ever’s Research & Development team conducted a study to assess the potential energy savings from a more sustainable management of the fermentation process. The analysis compared different yeasts from the company’s strain library, testing them in primary fermentations at different temperatures. This approach made it possible to identify a strain capable of adapting to a wide temperature range while maintaining the wine’s aromatic profile virtually unaltered.
The selected strain was named R.E.515, an acronym that emphasises its resistance to different working conditions.
Operating Modalities
The approach used for the study is called ‘Y-TEAM’, Ever’s exclusive method: from knowledge of the yeast and its potential, the best fermentation routes can be hypothesised.
The trial was carried out in Ever’s laboratories with the support and supervision of the ITALIANA BIOTECNOLOGIE biotechnology research and development centre with the evolution of what was learnt through the ‘Y-TEAM’ method, i.e. putting it into practice with different types of musts, so as to be able to investigate the peculiarities of the yeast on different matrices and under different real working conditions, adopting an omics approach.
The omics approach allows the genetic characteristics and genotyping of the yeast to be correlated with its behaviour, thus making it possible to predict its performance in different oenological contexts.
This approach is referred to as ‘Wine Learning’, and allows EVER to proceed rapidly in the development of yeasts with different oenological objectives according to the needs of the market, in order to provide employees with valuable tools for their work in the cellar.
The method adopted involves incubating micro-fermentations on 350ml theses, in duplicate, with continuous monitoring of fermentation kinetics.
Fermentation kinetics is verified by measuring the carbon dioxide produced under standardised temperature and pressure conditions.
The working conditions involve comparing the two fermentations, set up with the same nutritional and yeast dosage protocol, comparing only the fermentation temperatures with monitoring of the kinetics.
SELEZIONE R.E. 515
The selected yeast is a Saccharomyces cerevisiae r.f. bayanus, which is very vigorous, expressive and resistant to multiple stress conditions. It has a thermophilic attitude, so that at high fermentation temperatures it expresses excellent qualitative performance, revealing varietal aromatic precursors and completing the aromatic profile with fruity and floral esters.
To align with the strategy set out in the OIV 2020-2024 strategic plan mentioned earlier in this article, the ability to ferment at higher temperatures using specific microorganisms can be defined as “sustainable.” SELEZIONE R.E. 515 was isolated to produce high-quality wines while reducing the carbon footprint of wineries. It is recommended for premium white and red wines; its broad aromatic expression enhances both thiolic and terpenic varieties as well as more neutral ones. Thanks to these characteristics, it has proven excellent for fermenting musts from resistant grape varieties.
Results of Comparative Trials
During the experimentation phase, parallel trials compared fermentation at 17°C and 23°C. Analyses were conducted on both tests, yielding comparable results. Below are the graphs obtained from the average of the two analytical values, comparing the trials at the two different temperatures.
From each of these comparative trials, it is evident that differences due to varying temperatures are minimal.
For the most significant enological parameters, such as volatile acidity, total alcohols, esters, and acetates, the differences are practically negligible or insignificant. The achieved alcohol content is the same.
At this point, it is useful to focus on the specific differences: aromatic quality, fermentation duration, and associated energy consumption.
The following trial on Riesling was conducted at the two temperature extremes considered relevant for white wine fermentation. The most critical parameters from an aromatic perspective were summarised: negative attributes such as high-molecular-weight higher alcohols, the total sum of esters and acetates, and terpenes (as this is a semi-aromatic variety). It was observed that positive markers were significantly elevated, and upon tasting, the wine fermented at a higher temperature was comparable to, or even better than, the lower-temperature counterpart.
Let us now address the most significant aspect: fermentation duration and energy consumption. As shown in the following graph (Graph 10), the fermentation time for this example trial, confirmed across all previous tests, was 7 days at 23°C compared to 14 days at 16°C.
Even considering just this parameter, with the guarantee of comparable product quality, R.E. 515 stands out. However, evaluating the energy benefits—without delving into detailed energy balances—suggests an energy saving of at least 50%.
During fermentation, the energy released from sugar-to-alcohol conversion remains the same in both cases, as we are working with the same base, differing only in temperature. However, with a 50% reduction in fermentation time, greater heat exchange efficiency in refrigeration systems, and the net energy saving from reducing cooling by 6°C, this is certainly a non-negligible advantage.
Conclusions
R.E. 515 confirms itself as a highly resistant and versatile yeast, capable of delivering excellent fermentation results even at high temperatures. All laboratory tests, subsequently validated by industrial trials in wineries, have confirmed this characteristic with highly positive feedback from the winemakers who tested it. The extreme fermentation temperatures tested by EVER are not intended to define a strict protocol but rather to demonstrate that, despite a 6-degree difference between fermentations, the resulting wine is aromatically comparable and without defects related to volatile acidity. Why not take advantage of this opportunity to save energy and time? EVER suggests testing R.E. 515 for its contribution to the sustainability of alcoholic fermentation: a faster process that reduces environmental impact and allows for a higher rotation of fermenters, without compromising wine quality.
For more information, contact: info@ever.it
Valentina Giovenzana, Roberto Beghi, Ileana Vigentini, Riccardo Guidetti and Tiziana Nardi (2023) “Impact of fermentation-temperature management combined with specific yeast choice on energy savings in white winemaking”, BIO Web Conf., 68 – 02035. doi.org/10.1051/bioconf/20236802035.
Giovenzana, V., Beghi, R., Guidetti, R., Luison, M. and Nardi, T. (2023) “Evaluation of energy savings in white winemaking: impact of temperature management combined with specific yeasts choice on required heat dissipation during industrial-scale fermentation”, Journal of Agricultural Engineering, 54(3). doi: 10.4081/jae.2023.1523.
Valentina Giovenzana, Roberto Beghi, Paola Vagnoli, Francesco Iacono, Riccardo Guidetti, Tiziana Nardi (2016) “Evaluation of Energy Saving Using a New Yeast Combined with Temperature Management in Sparkling Base Wine Fermentation”. Am J Enol Vitic. 67:308-314 ; doi: 10.5344/ajev.2016.15115.
