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42 WINES&VINES July 2018 WINEMAKING A bout five years ago, Fermentis began to develop a brand of yeast that the company trademarked as E2U, which stands for Easy to Use. The goal was to develop a type of yeast that would make starting fermentations simpler. As all winemakers know, harvest is a crazy time of year where all manner of tasks can require more time and effort than there is time to complete them. If some critical elements could be simplified, it would help winemakers man- age the craziness of that time of year. I met with the Fermentis staff at the 2018 Unified Symposium to learn about the newer yeast strains they had recently released and the efforts they had taken with the E2U brand, in particular. The company's re-introduction of the E2U brand was part of a program to re- evaluate their entire yeast product line and to understand how their yeasts strains perform in a wide range of fermentation sources that are different from their primary target. Etienne Dorignac, technical manager of Fermentis, headed a project starting in 2016 to characterize many of the properties of the company's yeasts to ensure that the strains would produce the appropriate aromatic and structural elements in a reproducible manner in the wine, while also meeting the E2U man- date to be simple to use. A summary of the E2U process A symposium at the 10th edition of Enoforum in Vicenza, Italy, (May 16-18, 2017) included a discussion of the E2U process. The following summary of the E2U process is based on a You- Tube video of that symposium. In the process of industrial yeast strain preparation, the first step is to find a strain of yeast that has the characteristics needed for the desired wine style. Once the strain is identi- fied, the yeast production company has to design a method to grow the strain in a culture and environment that will create the largest biomass in a healthy state. The goal is to syn- chronize the growth of the yeast so that the majority of the yeast culture can be harvested at the ideal time — when the cells can be preserved in optimal condition for regrowth in the wine. From the standpoint of the yeast producer, this is where the rubber hits the road. As winemakers we understand that the rehydration stage is when yeast is at its most delicate and fragile condition in the fermenta- tion process. We know that small errors in this process can significantly affect the growth of the yeast in the fermenter and therefore affect the quality of the wine. The drying process must carefully reduce the moisture in a way that preserves the yeast membranes. One of the significant components of yeast membranes are phospholipids. These elements give the structural support to the membranes upon rehydration. Typically, wine- makers add yeast hulls to the rehydration mix- ture of the yeast. These hulls release sterols available to be absorbed by the freshly rehy- drated yeast thus strengthening their membrane structure. Helping the cell walls at this stage provides the initial vigor necessary to adjust to the osmotic pressure the sugars present and then the toxic effect the ethanol presents to the yeast throughout the fermentation. Dehydrating yeast too quickly can crystalize the phospholipids, which will destabilize the yeast membrane on rehydration, because as the yeast cells are dried, the cell shrinks in size from its fully hydrated state and it bends into overlap- ping folds. To ensure the best resistance to the drying process, Fermentis shapes the yeast in order to get, among others, a high trehalose content. This tactic provides structural help to the yeast cells and provides protection against the phospholipid crystallization. The company also adds an emulsifier to the yeast as they are drying to provide additional KEY POINTS Fermentis has developed new yeast strains that do not need to be rehydrated to conduct a fermentation. A plant-based emulsifier and fluid bed dryer provide a gentle drying process to protect yeast cells. A small scale trial fermentation finished dry with expected flavors and aromas. Skipping the Hydration Step in Fermentation A new line of yeast strains that do not need to be rehydrated prior to being added By Richard Carey MATRIX ESTERS No YAN deficiency/Same adjustments GV S107 CK S102 BC S103 VR 44 NDA 21 60,0 50,0 40,0 30,0 20,0 10,0 0,0 ■ 2-phenylethanol*10 (OAV) ■ Isoamyl acetate/10 (OAV) ■ Ethyl esters (C4, C6, C8, C10) (OAV) ■ Thiols (3-MH, 3-MHA, 4-MMP) (OAV) 40,0 35,0 30,0 25,0 20,0 15,0 10,0 5,0 0,0 GV S107 (*) CK S102 (**) BC S103 VR 44 NDA 21 (*) MATRIX THIOLS/ESTERS No YAN deficiency/No adjustments MATRIX THIOLS YAN deficiency/Recommended adjustments 80,0 70,0 60,0 50,0 40,0 30,0 20,0 10,0 0,0 GV S107 (*) CK S102 (**) BC S103 VR 44 NDA 21 (*) Figure 1a (top): Matrix Thiols/Esters. Figure 1b (bot- tom): Matrix Thiols. Figure 1c (top): Matrix Esters.