The source of yeasts in New Zealand wines

Abstract

The source and nature of yeasts responsible for the natural fermentation of grape must in New Zealand have been examined. Kloeckera apicuiata was the dominant species during the first stage of fermentation. but was later replaced by Saccharomyces cerevisiae, with lesser proportions of Saccharomyces chevalieri and Saccharomyces rosei. No fermenting yeasts were recovered from green grapes but most isolates from ripe grapes were of K. apiculata and S. cerevisiae. It was thought that the source of the fermenting species was the winery itself and previous season's pomace, in which they were found to be common; they were very rare in vineyard soil and were not recovered from fragments of bark and twigs of vines collected in winter. The vector by which fermenting species reached the ripening grapes was probably insects.

Diversity of yeasts in the soil adjacent to fruit trees of the Rosaceae family

“…Moreover, in a majority of these studies, the yeasts were identified on the basis of their physiological and morphological properties. The species of the former polyphyletic genus Trichosporon , which included Geotrichum capitatum , Dipodascus fermentans , Tausonia ( Trichosporon ) pullulans , and Trichosporon cutaneum , as well as Trichosporonoides spp., Endomycopsis bispora , and Aureobasidium pullulans were found in vineyard soil in England, and Saccharomyces cerevisiae , Torulaspora delbrueckii (reported as Saccharomyces rosei ), Pichia terricola , Clavispora ( Candida ) lusitaniae , Rhodotorula glutinis , and Vanrija ( Cryptococcu s) humicol a were detected in New Zealand (Davenport, ; Parle & di Menna, ). Metschnikowia ( Candida ) pulcherrima and Kregervanrija fluxuum ( Candida mycoderma ) were found in the surface soil beneath gooseberry and raspberry shrubs in August.…”

Overwintering of Vineyard Yeasts: Survival of Interacting Yeast Communities in Grapes Mummified on Vines

“…However, the soil is a rather unfavorable habitat for yeast overwintering because the soil microorganisms decompose the organic materials (for a review, see Treseder and Lennon, 2015 ) including the berries and their yeast colonists. Parle and Di Menna ( 1966 ) found very few fermentative yeasts in summer samples of vineyard soil and only Kloeckera (Hanseniaspora) apiculata in winter samples.…”

Assessment of dominance of added yeast in wine fermentation and origin of Saccharomyces cerevisiae in wine-making.

“…Recent ecological studies directly concerned with the actual yeast flora of grape surfaces (3)(4)(5)(6) showed that Saccharomyces yeasts are absent or occasionally present on grape berries, whose typical flora is represented by low ethanoltolerant yeasts and non fermenting species. This ecological situation is partially compatible with our knowledge of natural grape must fermentation.…”