Natural brew miso
Miso begins with the making of rice koji. It is said that the essential ingredient of the brew lies in the quality of the koji, but the experience and intuition of the brewer are also an integral part of the whole process.
Miso is made by mixing rice koji with steamed soybeans and salt, and allowing the mixture to rest in a wooden barrel over a certain period of time. At first, the sound of small bubbles will be heard as a sign of the fermentation process and indicate the rising temperature inside the barrel. Before being sold, the miso will move from the original barrel it was fermented in, to another wooden barrel when the fermentation process is finished. The original barrel will then continue to be used for fermenting the next batch of miso.
The making of koji rice
First, with the bare hands of the koji craftsman, steamed rice is distributed evenly over a surface, removing any clumps, and left to cool slightly. Once considered ready, a choice made through the intuition of the brewer, koji enzymes are sprinkled on the rice. Care for the rice koji continues for three more days, where it is placed in trays of natural cedar, in order to develop the fluffy texture which is the trademark of koji rice. The sense and care of the brewer here is critical, as natural conditions vary throughout the year, meaning climate and rice conditions have to be catered for. This is the reason why here at Ishimago we do not use the term factory.
The soybean steam pot
A huge steaming pot is filled with soybeans, which are then pressure steamed for about half an hour. As miso is traditionally made every spring, the sweet smell of steaming soybeans in the warehouse tells all of us that Spring has come.
The maturing process
Raw miso (where the ingredients are simply mixed together) is flattened by hand into a wooden barrel to ensure no air pockets remain. To ensure this condition continues (air is detrimental to the fermentation), the miso is also weighted with the equivalent of about ten percent of the entire weight of the raw ingredients. We have a unique yeast culture (called Ishimago Ebisu Yeast) within the storehouse that lives in the wooden barrels that has been used for over 100 years. The raw miso will ferment with the yeast culture and be aged for about eight months.
The miso is then transferred to another tub, meaning the miso that was at the top of the original barrel will now be at the bottom of the new barrel. This is an important process because it ensures an even quality of the final miso. The final product for sale is placed in a container in which the yeast remains alive (and therefore will give extra nutritious benefit, as well as continue to ferment at a slow pace). Ishimago’s miso is made from local rice and soybeans, and you can enjoy various flavors of our miso that have been blended on different ratios of rice and soybeans, and of course how long the miso has been aged also varies and creates various tastes.