The effect of Yeast Strain, Grape Solids, Nitrogen and Temperature on Fermentation Rate and Wine Quality

Abstract

The effect of four yeast strains, two levels of grape solids, two nitrogen levels and three fermentation temperatures viz. 10°, 13° and 15° C on total fermentation time (TFT) and wine quality was studied in a factorial experiment by employing a nitrogen deficient Chenin blanc must. It was found that the presence of solids, addition of nitrogen and fermenting at 15° C decreased TFT dramatically. Nitrogen was the only factor which also increased wine quality, the other two having a detrimental effect. At optimum levels of nitrogen, yeast strains WE 452 and WE 500 (VORI collection) reduced TFT without detrimentally affecting wine quality. In the case of WE 452, no solids should be present and fermentation conducted at 10° C -13° C, and in the case of WE 500, traces of solids should be present and a fermentation temperature of between 13° C -15° C should be utilized. Under these conditions WE 452 and WE 500 reduce TFT from C.76 days to as few as C.30 and C.15 days respectively.

The interactive effect of fungicide residues and yeast assimilable nitrogen on fermentation kinetics and hydrogen sulfide production during cider fermentation

“…The interaction effect of yeast strain and S 0 was significant with regards to fermentation duration ( P = 0.0002, data not shown). Fermentation duration is known to differ among yeast strains and the results of the present study show that effect of S 0 on fermentation rate also differs across yeast strains. The significance of this interaction effect supports the need to employ at least two yeast strains in studies investigating the impact of juice chemistry on fermentation performance.…”

Nutritional Deficiencies of Clarified White Grape Juices and Their Correction in Relation to Fermentation

“…Marly-Brugerolle & Sane, 1978;Ribereau-Gayon, Sudraud & Lafon-Lafourcade 1978;Wenzel & Dittrich, 1978;Williams, Ough & Berg, 1978;Buteau, Duitschaever & Ashton, 1979;Castino, Ubigli & Di Stefano, 1980;Houtman, Marais & Du Plessis, 1980a;Bertrand & Miele. 1984;Tromp. 1984).…”

“…However, if these fermentation conditions are too stringently applied, especially with regard to juice clarification, fermentation will be retarded or may even lag (Wucherpfennig & Bretthauer, 1970;Ribereau-Gayon, Lafon-Lafourcade & Bertrand, 1975;Haubs, 1976;Groat & Ough, 1978;Lafon-Lafourcade & Ribereau-Gayon. 1979 -Gayon, 1984;Tromp, 1984). In this respect Houtman & Du Plessis (1986) found that fermentations of juice filtrates of the grape cultivars Colombar, Chenin blanc, Semillon, Cape Riesling and Muscat d'Alexandrie under strictly anaerobic conditions at l5°C required an average of 60 days.…”

“…There are great differences in the fermentation rates which different yeast strains can maintain as well as in their ergosterol requirements and ability to complete fermentation. Other specific differences among yeast strains appear in the length of lag time after inoculation (Tromp, 1984;Houtman & Du Plessis, 1986). The amount of the inoculum, which seems to be independent of the yeast strain also affects both the lag time and overall rate of fermentation.…”

Effect of Copperoxychloride on the Fermentation of Must and on Wine Quality

“…It is clear that the latter fermentation and even that of the control treatment experienced lagging and after 80 days residual sugar was in fact still found in the wines. This can probably be attributed to the musts being very clear and virtually devoid of solids (Tromp, 1984;Houtman & Du Plessis, 1986). The 14 + 7 + 3 treatment nevertheless caused an additional lagging of fermentation while the fermentation curves of the musts of the other treatments (not shown) were identical to that of the control.…”