01 / ABOUT HACKOH

About Hackoh

A perspective learned from fermentation, and a guide to this site — what you can do here, and where to start.

01— FERMENTATION

Enjoying the Fluctuations

Making miso, which once supported family tables, was never just about preserving food. It was creative time rooted in daily life — feeling the seasons, conversing with invisible microbes. No two batches were ever quite the same, shaped by place and season, and that living practice nurtured a rich food culture unique to each region.

Even when you set the environment just right, in the end you have to leave the rest to the microbes. Fermentation also means accepting a kind of "fluctuation" that humans can never fully control.

And interestingly, this "fluctuation" has something in common with the AI now on the rise. AI may look like the ultimate expression of the digital, yet it too draws unexpected answers out of vast amounts of data. Fermentation and AI seem like opposites at first glance, but at a deeper level, they resonate.

The brand name "Hackoh" is a coined word for hacking (hack — putting to clever use) fermentation (HAKKO). We build up logic, piece by piece, to untangle the black box — and enjoy whatever uncertainty remains. We hope that through Hackoh, you'll get a feel for this "fermentation mindset."

02 — OPERATED BY MITSUURA BREWERY

About the Operator

Hackoh is operated by Mitsuura Jozo, a miso brewery in Yamaguchi Prefecture, Japan.

The greatest charm of miso lies in its "regionality" — the way its flavor differs from place to place. Wanting to protect that charm, we decided to keep making only mugi miso (barley miso), the taste of Yamaguchi. At the same time, we wanted to share the fascination of fermentation itself with more people, beyond the bounds of mugi miso alone — and that wish is what led us to launch this fermentation brand, Hackoh.

About Mitsuura Jozo ↗

03 — HOW THIS SITE WORKS

What You Can Do on This Site.

Hackoh consists of two parts: this website and an app. Their roles are clearly divided, so let's start there.

WEB — This Site

Learn it, make it, buy it.

Read how fermentation works, calculate the amounts for the miso you want to make, and gather your ingredients. This is your toolkit for everything before you brew — no account required.

APP — Hackoh

Brew it, nurture it, eat it.

Recording after you brew, predicting how aging is progressing, and letting you know when it's ready to eat. We stay by your side through fermentation for six months — your toolkit for everything after you brew.

Craft — Get Your Measurements, Then Brew

Decide how much you want to make, and we'll calculate the ingredient amounts. All the calculations happen right here on the site — no account needed.

Make Basic MisoRice miso — starting from the amount you want (in Japanese)Just decide how much you want to make, and we'll calculate the amounts of dried soybeans, koji, salt, and starter water for you. The koji ratio and salt level are fixed to a standard recipe, so even first-timers won't get lost.Brew a Regional MisoChoose from 20 varieties across Japan (in Japanese)Pick a traditional recipe from a region — Shinshu, Sendai, Saikyo, Hatcho, and more — and it scales to the batch size you want to make. Based on your region and brewing month, you'll also get an estimated aging period, plus a printable recipe and instructions.The Brewing Guide7 steps (in Japanese)Seven steps, from soaking the soybeans in water to packing them into a container to begin aging. If you have your ingredients ready, you can brew right along with this.

About Hackoh Craft

Hackoh Craft, which lets you freely combine proteins and koji, is currently an app-only feature. Free combinations require a safety check, and that check lives in the app — it isn't available on the website.

Learn — Choose How Deep You Want to Go

From a manga-style introduction to talk of molecules and numbers. Read it in order, or just skip to what interests you. 5 categories in all — no account required.

The Secrets of Fermentation12 episodes total, about 3 minutes each (in Japanese)An introduction told through conversations between Mugi and Hakkoh-chan — from brewing your miso, to waiting six months, to finally opening it. If it feels difficult, start here first.Fermentation Basics6 chapters total, about 43 minutes (in Japanese)From not knowing what fermentation even is, to confidently brewing your first batch of miso — six chapters you can read in order.Down the Fermentation Rabbit Hole6 chapters total, about 54 minutes (in Japanese)Enzyme speeds, shifting microbial populations, aroma molecules, and safety design — a closer look at fermentation through molecules and numbers.How Far Fermentation Reaches3 chapters total, about 28 minutes (in Japanese)How the same principle branched out across Japan's regions, took different forms around the world, and how long it's been with us.Fermentation Glossary500+ terms (in Japanese)Look up terms about koji, enzymes, and fermentation. If you come across a word you don't understand while reading, you can check it here.

App — The Six Months After You Brew

Miso's real journey begins after you brew it. The app reads how aging is progressing from temperature and elapsed time, lets you know when it's ready to eat, and keeps a record of your observations. This is work only the app does — you won't find it on the website.

About the AppScreens and what you can doSee how aging is progressing, as a number. Get notified when it's ready to eat. Keep a record of your observations. We introduce these features alongside the actual screens.About Your RecordsFor those who used the web aging log (in Japanese)Aging records have been consolidated into the app. Records you kept on the website haven't disappeared — log in to the app with the same account to pick up where you left off.

Release Status

The app is currently in preparation. Until it's released, please use Learn and Craft here on the website.

Ingredients & More

HACKOH STORECurrently in preparation (in Japanese)We're preparing a place to gather brewing ingredients like koji, beans, and salt. Please wait a little longer until we open.Ask Hakkoh-chanFermentation AI chat (in Japanese)Ask about anything you're unsure of while brewing, or anything you didn't understand while reading. Answers are based on our fermentation reference material.About Hakkoh-chanA small intelligence, close to fermentation (in Japanese)Not a teacher handing down the right answer, but a companion offering a perspective for noticing change. Here's a summary of that thinking.

About Selling Ingredients

The ability to purchase ingredients is currently in preparation. You can still use the amount calculator and check the instructions as they are.