I recently found out about the Ishii Miso Brewery located right in central Matsumoto so I wasted no time in going to check out – especially because they offer free tours, a special lunch with miso-inspired dishes, and miso soft-serve ice cream!

Ishii Miso was founded in 1868 and what makes it so special is that it is a now rare example of miso maker that still uses traditional methods to produce their miso. I took advantage of the short tour they offer so I could learn more about the process of making miso and Ishii Miso itself. The tour is free, can be done in both English or Japanese, lasts about 10-12 minutes, and once you’re done you can brag to all your friends about your expert miso knowledge, so I definitely wouldn’t skip it!

The tour starts in the “first year miso room” where you are greeted by huge, wooden fermentation barrels. These barrels are all around 100 years old and contain 4.5 metric tons (almost 5 US tons) of fermenting miso! Most miso makers now use stainless steel containers to ferment miso, but wooden barrels are much better because the wood allows aeration and the beneficial bacteria—yeast and lactic acid bacteria—to actually establish themselves in the sides of the barrels, helping to improve the flavor and protect against unwanted bacteria.

At Ishii Miso, perhaps their most prized product is their three year fermented miso. I was really surprised to learn that the not only is each 4.5 ton batch of miso transferred to another barrel at the end of each year, but they also “flip” the miso (a process called tenchi-gaeshi 天地返しin Japanese) once per year as well to aerate it in order to help the beneficial bacteria do their fermentation work as well as to help even out the flavors. The transferring and flipping is done by hand (with a shovel!), and according to tour guide, takes a whole day to complete for one barrel. Ishii Miso also makes a one year fermented miso, which also undergoes the flipping process one time during the year.

Unfortunately, less than 10% of the miso made in Japan is still made using traditional methods. Most miso is mass-produced in a factory using additives and heat to speed up fermentation so that a batch can be finished in 2-3 months. But, this fast-miso doesn’t have enough time to build up the complex flavors that you would get through natural, slow fermentation, so more additives and chemicals are added to attempt to make up for the loss of flavor. After trying Ishii’s miso or other traditionally made miso, you’ll definitely notice the difference whenever you eat miso made through mass-production processes.

On the tour, you’ll also learn other interesting facts about miso making in Japan like the regional differences due to the kind of koji (a kind of malted grain made with a beneficial fungus) used kome koji(rice malt), mugi koji (barley malt), or mame koji (soy bean malt) – and why miso gets gradually turns a darker brown color the longer it ferments (hint: it involves the increase of a compound called melanoidin produced through the Maillard reaction – the same reaction responsible for browning meats, bread crust, and coffee).

After the tour, check out the Ishii Miso Shop to taste their miso pastes, miso pickles, and other miso products. Of course, you can buy your favorite products to take home with you. I definitely recommend eating the special miso-inspired lunch, too! It includes a big bowl of tonjiru (miso soup with vegetables and pork), miso-grilled rice ball, rice ball with seasonal miso sauces like wasabi miso, miso pickles, salad with miso dressing, and a little miso ice cream. I’m also a big fan of the miso soft-serve ice cream, which is made with Ishii’s three year miso, so I’d recommend giving it a try too!

If you plan on having lunch, be careful about the time. Lunch is only available from 11:00 AM to 2:00 PM, but you can get soft-serve ice cream and buy things in the shop anytime between their opening hours of 8:00 AM and 5:00 PM.

See access info, hours and more on our Ishii Miso page here.