Monday, February 17, 2014

Move over Aspergillus Oryzae. Make room for Rhizopus!!


Yukae corrected my false understanding that the rice for the Rhizopus Oryzae Koji was unsteamed bricks of rice. As it relates to sake brewing as she has innovated, the "rice bricks" are not used. Steamed rice is used instead.

The main reason that the Japanese have traditionally been using only Aspergillus versus Rhizopus for Koji is that Rhizopus could not be grown on steamed rice...That is; until Yukae discovered how to do this at the University of Kitakyushu.

Over the course of the next few weeks, I hope to learn more about this unique method. As of now, the details or procedures for fellow brewers to learn so that they might consider Rhizopus for their own production considerations will have to wait.

I am sorry for my error in understanding my Toji and Yukae Sato, which will serve as fuel for me to improve my language abilities. Gordon 02/19/14.


It is time to honor a feat of ingenuity that, regardless of age or gender, is admirable and remarkable. I consider this a breaking story for those of you sake otakus out there! Let’s give Yukae her due.
Ms. Yukae Sato, age 22, has invented a new, unique method for creating koji that merits respect and praise --a method unique in the annals of sake.
Koji made from Koji-fungus on steamed rice is the fulcrum of sake. Yukae-chan has invented (patent pending) a process using new ingredients which supplements the traditional Aspergillus Oryzae with Rhizopus Oryzae… with provocative results. Take my word for it. Her sake is delicious. Not only is this remarkable discovery for its own sake (there’s that word again!); it offers new choices for sake brewers seeking to carve a niche in a competitive marketplace.
By way of background, Koji produces a variety of hydrolytic enzymes. Diastatic enzyme (glucoamylase) especially influences the quality of fermentation. Koji produces glucose by the action of the saccharification enzyme from the starch of rice. It is vital to produce koji with high glucoamylase activity for the improved quality. Yukae mixed koji of Aspergillus and Rhizopus to increase the glucoamylase productivity and create new brewing characteristics.
In a lab and in a brewery, comparing with a control batch, the mixed culture koji was 1.8 times in the succinic acid and 1.3 times in the lactic acid. It is thought that the abundant acid in the sake of the mixed culture koji is due to its origination from of Rhizopus.
The increase of acids is provocative, but if it doesn’t yield a delicious taste, then does it matter? Again, rest assured, Yukae’s sake is delicious. Notes of bursting grapefruit, a billowing creaminess, and a complexity that baffles…sweet, then sour, then a dry finish.

Hibikini no Mori is a junmaishu, a blend of 701 & 901 yeasts; with 80% having a seimaibuai of 70%. This remaining 20% was made with Rhizopus Oryzae in the traditional brewing method. Can I get a “Mind Blown?!”
In an era where nearly 75% of women under the age of 30 recently said that they enjoyed sake only very rarely, let Yukae’s triumph be celebrated with a toast of her sake. May our trade use her innovation to bring the glory of nihonshu to new customers, if not new heights.

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