Advantages for winemaking of the selection of a functional aromatic yeast, its E2U™ production and the importance of inoculation monitoring by flow cytometry.
Flow cytometry applied to oenology: a technique adapted for dynamic monitoring of wines
Matthieu DUBERNET, Chairman and CEO – Laboratoires Dubernet Oenologie
Oenological interest of the selection, the E2U™ production method and the timing of inoculation of a functional aromatic yeast
Arnaud DELAHERCHE, Technical Manager – Oenology – Fermentis
Industrial winemaking processes are based on the use of Saccharomyces cerevisiae starter cultures that can guarantee the stability and reproducibility of the processes through the correct behavior of these yeast populations.
Flow cytometry is an innovative technique that allows dynamic monitoring of the population of microorganisms; this session will illustrate its interesting potential.
Next, an experimental case will be shown based on the study of two yeast inoculation techniques: bioprotection applied to the grapes or during the pre-fermentation phases and conventional inoculation that includes direct inoculation after racking.
As regards the time of addition, it was carried out at four different times: (i) directly on the grapes during reception, (ii) in the must after crushing or (iii) pressing and (iv) in two doses added to the must after crushing and racking, respectively.
In the case of conventional protocols, four moments were studied: (v) and (vi) respectively with direct inoculation just after decanting and temperature increase, (vi) rehydrated in water at room temperature and with a gradual acclimatization method after decanting and temperature increase.
In the bioprotection protocols, it was observed that SafOeno HD A54 could be inoculated both in grapes and during prefermentation phases only if low and controlled temperatures (<10°C) were maintained to slow down the onset of alcoholic fermentation and avoid sedimentation problems.
SafOeno HD A54 yeast inhibited the development of non-Saccharomyces and Saccharomyces cerevisiae yeasts when inoculated at a dose of 20 g/hL before pressing. Inoculation after pressing resulted in the most rapid onset of alcoholic fermentation.
In the conventional inoculation mode and in musts with a high load of indigenous microflora, it was demonstrated that SafOeno HD A54 yeast obtained by the E2U™ process could be inoculated immediately after cold settling or after temperature rise without implantation or fermentation problems. It also demonstrated its particular organoleptic profile (intense amyl notes). This study showed that, for certain yeast strains, E2U™ technology in combination with early inoculation guarantees obtaining the desired type of wine.
