WINETECH Technical Yearbook 2019

SEQUENTIAL INOCULATION OF STARMERELLA BACILLARIS AND SACCHAROMYCES CEREVISIAE – MAIN EFFECTS

CARIEN COETZEE: Basic Wine, Stellenbosch KEYWORDS: Sequential inoculation, Starmerella bacillaris , Saccharomyces cerevisiae . SEPTEMBER 2019

In a recently published study researchers evaluated the sequential inoculation of two yeast species compared to one and the effect it had on wine chemistry. INTRODUCTION Previous studies have shown that fermenting juice with indigenous yeast can potentially increase the complexity of the wine due to the contribution of various yeast species (Belda et al ., 2017; Englezos et al ., 2016A; Guérin-Schneider et al ., 2012). However, the lack of reproducibility and predictability of these types of ferments has led winemakers to opt for predictable commercial yeast preparations. The complexity provided by indigenous ferments can, however, be

simulated to some extent by inoculating the must with “wild” yeast strains, thereby ensuring a large enough yeast population and desirable conditions. A sequential inoculation with the trusted alcohol tolerant, Saccharomyces cerevisiae , can then be done to ensure successful completion of the fermentation. A study done in 2018 by Englezos and co- authors titled, “Volatile profile of white wines fermented with sequential inoculation of Starmerella bacillaris and Saccharomyces cerevisiae ”, aimed to investigate the effect of these yeast strains (or combination thereof) on the aroma profile in four different white wine varieties (Englezos et al ., 2018).