Physicochemical property changes during the fermentation of longan (Dimocarpus longan) mead and its aroma composition using multiple yeast inoculations

Mead is a traditional drink obtained from diluted honey with the appropriate yeast inoculations. However, the production of mead is time‐consuming, and the process often takes several months to accomplish. During the elaboration of mead, sluggish and stuck fermentations often occur and lead to the production of undesirable flavours. To improve the condition of longan mead production in Taiwan, multiple yeast inoculations with different strains of yeast were examined in this study. The physicochemical properties and mead aroma compounds were measured. Longan mead without multiple inoculations, but with added yeast nutrients, displayed a sharp increase in ethanol content compared with the inoculated groups without yeast nutrients. However, the physicochemical properties of every mead reached almost the same endpoint at the end of the fermentation time (day 22). Moreover, differences among the groups were observed in their aroma compounds. Some aroma compounds, such as 2‐methyltetrahydrothiophen‐3‐one, 1‐propanol and 2‐methylbutyl acetate, were only found in the double‐inoculation groups, whereas other aroma compounds, such as phenethyl acetate and linalool, were only found in the single‐yeast inoculation groups. These results demonstrate that multiple inoculations have a positive effect on longan mead fermentation. This technique could assist local producers in elaborating a longan mead of acceptable quality. Copyright © 2013 The Institute of Brewing & Distilling