*Originally published in 2015
Often makgeolli recipes will suggest adding 효모 or yeast to the brew to ensure it’s success. Adding beer or wine yeast will help to off set some of the unpredictability of the nuruk. Unless you isolate all the organisms in the nuruk yourself you never really know what different types of yeast are in your brew converting the sugars into alcohol.
Each type of nuruk will have it’s own combinations of yeast and molds. Some will be commonly seen players such as Aspergillus oryzae but some also have lesser studied molds as well such as some species of Lichtheimia (Yang et al., 2011). The same goes for yeasts as well. While some nuruk will have our friendly Saccharomyces cerevisiae others will have a prevalence of other yeasts (Song et al., 2013). One such yeast, Pichia anomala, produces off flavors such as ethyl acetate, which gives a solvent like smell and taste to the final product (Ji Ho et al., 2013). It is the purpose of this experiment to curb any Pichia growth by adding additional Saccharomyces cerevisiae to the brew in order to prevent the accumulation of off flavors.
Since it is well known that different strains of Saccharomyces cerevisiae will develop different types of flavors and scents as well 3 different types of beer and wine yeast that use Saccharomyces cerevisiae will be tested.
Objective: To use beer and wine yeasts in Makgeolli and determine the flavor and smell profiles of each brew.
Materials:
-Materials used in the godubap procedure
-50g Songhak nuruk (American wheat (the yellow bag))
-500g Chapssal
-750ml water
-1/2 tsp of yeast (see experimental sets for what type)
Procedure:
-See godubap procedure
Sets:
Set 1 – No yeast
Set 2 – Lalvin wine yeast ICV D47
Set 3 – Safale US-09 Dry Ale yeast (Fermentis)
Set 4 – Safbrew S-33 Dry Brewing yeast (Fermentis)
Notes -The yeast was soaked in 100ml of lukewarm water for 20 minutes before added to the brew.
-The nuruk was soaked in 650ml of lukewarm water for 10 minutes before added to the brew
Results:
The different yeasts definitely gave each brew a distinctive quality. Set 2 and 3 both had a very dry, alcoholic, almost bitter taste to them. Set 1 and 2 had a slightly sour sweet taste with set 2 being slight milder.
Bibliography:
Ji Ho, C., Hwan Yeo, S., Park, J.-H., Choi, H. S., Gang, J.-E., In Kim, S., … Ra Kim, S. (2013). Isolation of aromatic yeasts(non-<i>Saccharomyces</i> <i>cerevisiae</i>) from Korean traditional <i>nuruks</i> and identification of fermentation characteristics. Agricultural Sciences, 04(05), 136–140. http://doi.org/10.4236/as.2013.45B025
Song, S. H., Lee, C., Lee, S., Park, J. M., Lee, H. J., Bai, D. H., … Park, Y. S. (2013). Analysis of microflora profile in Korean traditional Nuruk. Journal of Microbiology and Biotechnology, 23(1), 40–46. http://doi.org/10.4014/jmb.1210.10001
Yang, S., Lee, J., Kwak, J., Kim, K., Seo, M., & Lee, Y.-W. (2011). Fungi associated with the traditional starter cultures used for rice wine in Korea. Journal of the Korean Society for Applied Biological Chemistry, 54(6), 933–943. http://doi.org/10.1007/BF03253183
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