2026-06-18
A study published June 11 in Scientific Reports found that common winemaking treatments can change the vitamin content of grape must in ways that affect how Saccharomyces cerevisiae ferments and how the finished wine smells.
The research focused on products widely used in cellars, including fining agents such as bentonite and oenological carbons, as well as yeast-based nutrients. According to the paper, bentonites and carbons depleted several B vitamins from grape must, while yeast derivatives released significant amounts of those nutrients back into the medium.
The authors then examined one vitamin in particular, thiamine, also known as vitamin B1. Using bentonite to alter B1 levels in a real grape must, they tested different yeast inoculation methods, including active dry yeast and cells that had been precultivated to change their physiological state and internal B1 reserves.
They found that the initial level of thiamine had a significant effect on fermentative activity. By contrast, the impact of inoculation method appeared to be tied more to how well the yeast adapted to a liquid medium than to its internal B1 stores.
The study also linked thiamine availability to a broader increase in volatile compound production, a key factor in wine aroma. When B1 was added back to a bentonite-treated must, the volatile profile returned to that of the untreated control, the researchers reported. That result suggests thiamine depletion is a major reason bentonite treatment can alter wine volatile composition.
The work identifies a possible mechanism behind a long-observed issue in winemaking: treatments used to clarify or stabilize must may also shift fermentation behavior and aroma outcomes by changing micronutrient availability. For producers, that could matter beyond academic interest. A better understanding of how fining agents remove vitamins, and how nutrient additions restore them, may help wineries adjust formulations, protect fermentation performance and reduce unintended changes in aroma.
The paper said the findings confirm the importance of thiamine in vinification and help explain how fining agents can modify wine characteristics. The authors were Fabien Garces, Jonathan Picart, Matteo Bosaro, Emilie Riviere, Christophe Morge, Hervé Alexandre and Chloé Roullier-Gall, affiliated with Université Bourgogne Europe, Institut Agro, INRAE in Dijon; Sofralab SAS in Magenta, France; Italiana Biotecnologie in Montebello Vicentino, Italy; and Laboratoire Océania in Vallet, France.
The grape musts used in the experiments were provided by the Cooperative Winery of Montagnac in France’s Hérault department. Funding came from the ANRT under grant No. 2023/1579 and from the HARMI project, part of the France 2030 program managed by the French National Research Agency. The authors declared no competing interests.