When inducing malolactic fermentation (MLF) in wine, bacteria cells inoculated at the end or after alcoholic fermentation (AF), can find harsh conditions such as low pH, high ethanol and SO2, difficult to adapt to. To overcome this problem, bacteria inoculation in must or at the beginning of AF has been previously investigated. In this study, we compared MLF induced by bacteria inoculated in must of partially dried grapes (simultaneous yeast and bacteria inoculation or co-inoculation) with bacteria inoculated after AF, in wine characterized by pH 3.3 and 14.3% volume ethanol. In the yeast-bacterial co-inoculated trials, malic acid consumption was completed in 32 days, compared to 72 days in trials inoculated with bacteria after AF. In the trials not-inoculated with bacteria, the MLF totally failed. No additional increase of acetic acid and D-Lactic acid was observed in wines obtained with simultaneous AF/MLF compared to those produced by sequentially AF/MLF. Citric acid was not degraded in all trials. In our experimetal winemaking conditions yeast-bacterial co-inoculation resulted in a reduction of MLF time without having wine quality depreciation. This practice promises interesting results in the production of wines that are difficult to get through MLF.
Comparison between simultaneous and sequential alcoholic and malolactic fermentations for partially dried grapes in the production of Amarone style wine
ZAPPAROLI, Giacomo;Veneri G.;
2007-01-01
Abstract
When inducing malolactic fermentation (MLF) in wine, bacteria cells inoculated at the end or after alcoholic fermentation (AF), can find harsh conditions such as low pH, high ethanol and SO2, difficult to adapt to. To overcome this problem, bacteria inoculation in must or at the beginning of AF has been previously investigated. In this study, we compared MLF induced by bacteria inoculated in must of partially dried grapes (simultaneous yeast and bacteria inoculation or co-inoculation) with bacteria inoculated after AF, in wine characterized by pH 3.3 and 14.3% volume ethanol. In the yeast-bacterial co-inoculated trials, malic acid consumption was completed in 32 days, compared to 72 days in trials inoculated with bacteria after AF. In the trials not-inoculated with bacteria, the MLF totally failed. No additional increase of acetic acid and D-Lactic acid was observed in wines obtained with simultaneous AF/MLF compared to those produced by sequentially AF/MLF. Citric acid was not degraded in all trials. In our experimetal winemaking conditions yeast-bacterial co-inoculation resulted in a reduction of MLF time without having wine quality depreciation. This practice promises interesting results in the production of wines that are difficult to get through MLF.
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