DOX system (DOX-60F/DOX-30F) rapidly evaluates the total number of microorganisms, coliforms and Escherichia coli

#22 Happy New Year! Let’s Make a Toast to Multiple Parallel Fermentation!


Professor Emeritus at Hokkaido University

Advisor at Japan Food Research Laboratories

Biography of Dr. Isshiki


I wish you enjoy a happy and prosperous New Year.


When I was young, kids were forced to drink alcohol once a year on New Year’s morning.  It was a drink called “Toso” with an odd taste and smell.  This tradition seems to have been fading.  


Figure1 shows a part of sake casks dedicated to Meiji Shrine.  Who’s gonna drink the content?  If someone drank it all alone, the person might be in big trouble as a punishment by the god of the shrine.  The wooden square container (“Masu”) in the bottom right corner of the Figure is a souvenir from a social gathering of Food Hygienics Society of Japan held in Kyoto.  As the venue was close to Fushimi, one of the Japan’s most famous sake brewing areas, a number of delicious sake brands were displayed to be served at the party.  Other than Fushimi, there are many places that produce good sake around Japan.





Three methods for alcoholic fermentation


Sake holds a unique position in the world’s alcoholic beverages.  Its fine flavor is renowned across the globe representing Asian traditional multiple parallel fermentation beverages.  Figure2 simplistically shows fermentation processes of wine (representing simple fermentation), beer (multiple sequential fermentation), and sake (multiple parallel fermentation).




It is said that sake brewing requires the most sophisticated skills among alcohol making methods.  As shown in Figure3, hydrolysis of starch using Aspergillus oryzae and alcoholic fermentation by yeast occur simultaneously in a tank.  Starch turns into glucose, and glucose changes to alcohol.


As for wine, yeast conducts alcoholic fermentation using sugar contained in grape berries (see Figure2).  Yeast is directly added to juice of crushed grapes.  This method is called simple fermentation. 


Barley seeds, raw material of beer, contain starch.  Yeast does not ferment starch to produce alcohol in a single step.  In beer making, starch changes to maltose and its enzyme is utilized.  Barley starts to germinate by the addition of water and enzyme is induced.  Then starch is broken down and maltose starts to be produced as Figure2 shows.  Yeast is added to wort containing maltose to undergo alcoholic fermentation.  These two processes --- barley (starch) to maltose and maltose to alcohol --- occur in separate tanks and this method is called multiple sequential fermentation.  Please refer to #18 of this column series.




Sake is made from rice.  Rice contains starch, which needs to be converted to glucose so that yeast can be used for alcoholic fermentation.  After rice is steamed and cooled down, Aspergillus oryzae is spinkled on rice so that enzyme is produced.  Enzyme hydrolyzes starch into glucose.  By using this glucose, yeast undergoes alcoholic fermentation.  In sake-making, two processes, starch to glucose and glucose to alcohol, occur simultaneously in one tank.  This brewing method is called multiple parallel fermentation.  Although few drinks are brewed in this way around the world, multiple parallel fermentation has the excellent advantage of producing drink whose alcohol concentration is more than 20% without distillation.


Sake brewery, one of the multiple parallel fermentation method, is said to be the most sophisticated fermentation method in the world.


Sake brewery, one of the multiple parallel fermentation method, is said to be the most sophisticated fermentation method in the world.



1) Wada, M., Tajahashi, T. supervision (2015), Nihonsyu no Kagaku (Science of Sake), Kodansha Ltd.


nach oben