The Koji Fermenteria

Sandy proof layout !!
I made the layout of the room once used for koji workshop Sandy proof 🐶
Hardwood floor is so unkind to aging dog like him (it almost like a skating rink ⛸️) so we brought out all the rags and small carpets in the house and did some nice patchwork!
Now, he has his own wheelchair🦽, full covered harness and anti-slip socks… Any supporting tools, you name it and I got it for him. I know he is spoiled 🤣

He is also being spoiled very much with the food aspect. I use koji in various ways and he loves it. I truly believe koji generate his fighting spirit! With all the problems and restrictions he has, he still tries to enjoy his life, walking around in the garden in lovely British summer.

Maybe it won’t be anyone else’s use but I will share how I use koji in his (and Maisy’s) diet next time 😊

久々の白夜製麹💕
#白夜 white night is one of my favourite spore. It is one of the spores available from and widely used to make ginjyo type sake. Its gluco-amylase production capability outstands.
Every time I make koji with it, I am stunned by its elegant appearance. When I make amazake with it, the taste never betrays my expectation. It gives pure sophisticated sweetness (Not recommended to make miso with it though 😅)

This time I am planning to use it for refreshing my sakadane and making doburoku.
I 💓 白夜

I am over the moon to receive the lid of my favourite crock, beautifully repaired with kingsugi done by . I can’t be more grateful. Thank you so much!

I was shuttered when it was slipped out of my hand and broken in pieces… although I managed to save my 60 year old nukadoko. I was at a loss and then my good friend Nicole kindly offered help 😭🙏🏻😭

Initially I chose red urushi finish but changed my mind to sliver at last minutes (you can see how the repair progressed in ) My indecisiveness costed extra work for Nicole 🙇🏻‍♀️ but she generously apply my last minute request. I am very grateful and happy with my final decision. It is sophisticated, graceful and very Japanese! Bang on to my personal taste💕

My crock is now very original, only one in the whole world! Without saying I love it more than before.

Best example that misfortune can turn into many layers of happinesses 😊 Not only the beautifully done lid itself, but also Nicole’s kindness, generosity and big heart made my heart very warm

Natto soup 納豆汁　
Another example why I think our ancestors er genius! This time they are the magician of soybeans🫛 I am sure you agree😊

This is the regional cuisine of northern Japan called natto jiru. Very similar to miso soup. But use more ingredients. I used Gobo (burdock) , carrot, mushroom and spring onion as well as tofu and age (deep fried tofu) which is kind of regular ingredients for miso soup. Last, but not least, of course, I added ground natto just before serving.

This is my personal preference, but I tend to use the blend of young and mature miso (in order to aim at umami and subtle sweetness)

What is great about this food is four different forms of soybeans are used in this simple dish to give variety of texture, depth of flavour and taste. Miso, tofu, age and natto.

This is even more delicious on the next day!
Needless to say, this is very nutritious and healthy!

#納豆汁 #日本のご先祖様ってほんと天才

Sakadane yeast 酒種酵母

80 min proofing test successfully PASSED 👍🏻
5 days startup period is the continuous selective process of able bodied yeast. Those not meeting the standard are gradually eliminated during 4 step batches.

Small portion of the final starter is mixed with bread flour and tested whether it doubles in 80 min.
Here is the result 💕

Preparing Sakadane yeast (rice koji bread starter) with brilliant guidance of

Sakadane 酒種 starting method is a great invention by our Japanese ancestors using three different forms of rice (raw rice, cooked rice and koji rice) with specific ratio at specific timing. It takes 5 day and requires 4 batches, each of which succeeds small quantity from previous batch and each time different ratio of rice is introduced. Sounds complicated? Yes, I have to agree😅. But this is utterly sophisticated system to be able to eliminate unwanted types of yeast & other microbes and only target type of high-performance yeast will remain in last batch.
Coming up with this elegant system with hardly no knowledge of microbes, I truly believe our ancestors are the magician of rice!

Bread made using sakadane yeast is highly digestible, remains soft for a long time, carries unique texture (もちもち💕), with subtle hint of sake, and also less likely to become mouldy! All so good, isn’t it? In my opinion, it worths bit of effort to enjoy these benefits!
My starter is in 4th batch so I am nearly there!

Can’t wait to make bread with this next week😊

is running wonderful online koji and baking classes. Thoroughly recommended😉

Toranomaki 虎の巻 from

the koji fermenteria としての私の活動の背景をとってもよくまとめてくださっていたのでshare🥰:

THE KOJI FERMENTERIA
Haruko Uchishiba is passionate about koji, and passionate about raising awareness of its amazing ability. “Koji is a hidden gem in Japanese food culture,” she explains. “Miso, soy sauce, mirin and sake are all made by koji fermentation. They are made from only a few simple ingredients but koji turns them into absolute essentials in Japanese cuisine. “

“Koji has a magical power,” she continues. “It can transform food into something nicer by creating taste and flavour that the original ingredients don’t have.” For Haruko, teaching people about koji is revealing its “magic trick”.

To teach the magic trick, Haruko founded Koji Fermenteria, through which she makes and sells koji products, as well as hosting events and workshops to spread the word. “My aspiration with Koji Fermenteria is to help chefs master the koji magic, so that they can make the best use of koji to create wonderful cooking,” she says. “Hopefully then it will sink into British food culture, and I can feel I have contributed a tiny bit to British food culture.”

“Making koji is very therapeutic,” she says. “It is not just a substance; it is a living thing and reacts to the environment or the conditions that I give to it. When things don’t go as I hope, I look back at what I have done wrong to upset them and then I rectify my approach and the koji can give its response back to me. It’s a mutual communication. I found making koji is a good way to train your communication skills and achieving better communication skill is an extra bonus of dealing with koji”



Produced by

Honoured to be featured in newly published “虎の巻TORANOMAKI” the definitive guide of Japanese run restaurants in London by as one of the food specialist.

This is an excellent and inspiring book to enable you to explore truly authentic Japanese food culture while you are in U.K. Wide variety of restaurants and specialists are presented with their unique ethos and stories behind (even with their recipes). I am sure it will make you feel like visiting all of them one by one! Certainly I do😊

Pick up your own copy at Onitsuka Tiger store in Regent St!

Produced by
Special thanks to Onitsuka Tiger and MAP studio

Did you know that Tesco and Waitrose collect soft plastics, such as crisps packets, plastic bags, food wrappers etc? I didn’t until quite recently ….

I have been hating to see our waste bin filled with soft plastics (because our council doesn’t collect them as recyclable waste). So I was delighted when I found the socially responsible attitude of some big supermarkets (after all they are perhaps the largest distributors of the soft plastics 🤣)
Collected soft plastics are recycled to produce bin liner etc. Make sense doesn’t it?

I made inquiry about how I can find which of their branches collect soft plastics. The response speed was fairly impressive. Both of them replied almost immediately!
Shame that Sainsbury’s used to collect them but not any more …

Now that I bring soft plastics for recycling, our general waste bin is almost empty before collection day ✌🏼😊✌🏼

I am aware that recycling them requires energy which produces CO2🥲 However collecting soft plastic at home makes me constantly aware of how much amount of soft plastics are involved in my shopping activities which makes me more environmentally conscious !

Rare chance!
I have small numbers of beautiful Tokoname crocks (mini, 180ml and 360ml) on sale. These will make lovely Christmas present for sure💕

I have
180ml (h:85mm, dia:80mm)
Brown x 1
Blue x 1
White x 1
Dark navy x 2

360ml (h:110mm, dia:90mm)
Brown x 1
Grey x 1 (sorry no box)

180ml £10 ＋postage
360ml £12 ＋ postage

You er more than welcome to collect it from n12 as postage is rather expensive for the value of items💦

Alternatively I will be Christmas market in Muswell Hill next Sunday afternoon. So you can collect it from there!

DM me if you er interested.
First come first serve basis
Sorry 🚚 uk address only

Unusual position to steam rice. On the dancing platform🤣

Always feel a bit nervous when I have masterclass away from my residence as there are bound to be some unknown factors. But this time it was rather amusing.

The portable hob was on the worktop and the steaming pan on top of it was rather tall so I needed to stand on the high stool to do “nukegake” (the special method to steam rice evenly which requires close monitoring of the surface colour of the rice)

It was such a fun to be able to introduce some unknown charms of koji.

Koji really has huge potential in the area of
- SDGs (degrading plastic)
- Lvestock farming
- Agriculture
- Medical and pharmaceutical

let alone the famous food application we know very well👍🏻

I truly believe koji (as well as other minutes creatures) has potential to save the future of this planet 🌏

#お立ち台で抜け駆け　

Photo shooting session of koji at midnight on my own 💕 So therapeutic !
Choosing a beauty queen for individual shot 🤣

麹のフォトセッションが楽しすぎる。深夜に一粒一粒の麹と静かに対話する私って、もしかしたら相当変な人かも(今更)

After getting familiarised with koji through “pocket koji”, the next level I am taking my students to is “takeout box koji”

This is slightly more sophisticated and koji is grown in more controlled manner, but it is still far from intimidating 😅

Through these steps you can become better friend with koji and naturally build rapport with them

Like pocket koji, students bring inoculated koji to home and grow it in their own setting. Growing experience is share in SNS so you don’t feel left alone😅 I am pleased to say that success rate has been very high👍🏻

This is a part of learning in 3 days “All about koji” class

I made 3 short video clips to show what we are doing on each day of three days comprehensive koji class “all about koji”.

As you will see, there are lots of info, activities, tastings and even two meals (one western and one Japanese bento 🍱)

Lots of information given is from my own experiences so you will get something which you will never learn from just reading the books!

Fun guaranteed!

My aspiration is to make more koji fan. If you fall in love with koji it will make me very happy💕

Pocket koji there after!
Last week I spent wonderful 3 days with .sam.black in my koji workshop with mutual skill exchange. Gosh it was fun🤩

As one of the extra activities three of us grew koji in our pockets. This time I changed the material of the incubator (bag😅). The bag used was sandwich bags with one side greaseproof paper and another side clear film and the result by far exceeded my expectation! It grew almost as good as my usual method😳 (悔しいけど笑). And it was not only me, all three of us succeeded!

You can’t make large quantity in one go but still can make enough to make 100g of shoyu koji or shio koji.

We all agreed that this is a wonderful activity to get to know koji and fell in love with them❤️

On 22nd October I participate in the fermentation festival at and you will have an opportunity to grow koji in your own pocket! Join me if you er interested!

#ポケット麹

Failure 😑 チーン
I had a sudden urge to grow koji on raw coffee beans (intended to make tamari-style shoyu)

I knew it is hard (much harder than brown rice to skin) so koji wd struggle😅

I soaked and steamed and confirmed that water retention was 40%

After two days no sign of germination nor slightest hint of chestnut smell🤣

Nevertheless it smells nice so perhaps I will dry them and use it instead of wheat in my next shoyu making

#コーヒー麹見事に失敗

Always super happy to witness koji making people smile 💕

Earlier last week, I had a fabulous opportunity to host two koji workshops for great chefs, & his wonderful team , and a super baker . It was so nice to have such responsive and enthusiastic attendants!!

Prior to the workshops I made big efforts to redesign my classes to convey koji’s charm to the fullest extent, not because these people are influential, but because I was certain that they will draw koji’s potential in the best possible way! Hopefully I have done a good job.

Through this project I came to realise that this is the activity I want to do more of. Passing on my geeky experiences to able people who will extend it further and beyond. I want to see koji flourishing even more.

It would be wonderful to imagine that I will be amazed by new ideas and be able to enjoy new tastes and flavours I have never experienced 😊 If I can contribute a tiny amount to this future, I couldn’t be happier!

If someone out there is curious about the details of the workshops, the link is on my bio page. Workshops can be arranged on request!

I knew that koji is a aerobic creature but what I didn’t realise was koji sucks oxygen so powerfully like this😳

Every time I opened the bag I fed air to them but soon after that the bag became vacuum again!!

Perhaps I should be more generous to feed them more air in my usual koji making 🥰 so they wd be happier and make more enzyme for me to use in my ferments!!

Pocket koji making is a good tool to become better friends with koji 💕

I am growing koji in my pocket using my body temperature.
This is obviously not the best way to grow quality koji but I think this is the best way to get yourself familiarised with koji.
3rd and 4th photo are taken about 24 hour after inoculation and you can see they started to germinate nicely😊
It also started to become warm and emit nice aroma💕💕

I am using aspergillus kawachii here because it is the spore best suited to this condition.
I am incorporating this activity at the end of the koji introduction workshop for professional chefs which I am redesigning at the moment. Stay tuned!

Wow! My dream came true💕 I am so moved 🥹

Ever since I started my koji activities, my biggest aspiration has always been to witness how wonderfully koji would flourish outside native Japanese context. This is exactly what I experienced last week and it was far beyond my expectation !

Last week I was fortunate enough to dine at opening family and friend event with my husband. Humo is a new restaurant to be publicly opened this week, run by a talented Colombian-born chef who was trained with renowned Michelin star chef Kazutoshi Endo. I have been collaborating with Miller last few years sharing and exchanging koji experiences etc. The restaurant has very unique concept that all cuisines are cooked by wood fire without gas and electricity. Menu is predominantly product-led rather than by specific cuisine but influenced by precision of Japanese cooking technique as well as Miller’s Columbian background (described in Big Hospitality on 9 Dec 22)

There are a lots of good things I want to tell, but it is going to be endless 😅 so I just focus on the menu which involves koji.

“Amazake cocktail”
I never expect amazake (citric in particular) to be combined with champagne and mugi shochu, let alone the fragrance of birch! It is so refreshing with light touch backed by subtle tartness and umami from shiro koji. Well, shiro koji is used to make shochu so naturally they bounds to be a perfect pair. How did I not think of it. The cocktail is so beautifully designed and I am taking my hat off with respect!

“Mugi koji ice cream sandwiched with rum baba”
I was so privileged to be a first person to taste this heavenly wonderful dessert (this was not on the menu yet)
Deep umami and gracefully creamy ice cream is a perfect match with rum baba! I was explained that the recipe is still under development (for me it was already perfect!) and can’t wait to try the completed version (it will be beyond my imagination 😊)

This restaurant and these menu are absolutely not to be missed. I can’t recommend strong enough to rush to book your table!

So proud that my koji is associated with these wonderful menu

Christmas market this coming Sunday the 11th 12-4pm @ Hornsby Parish Church - muswell hill

Last but not least!
We have three Tokoname crocks (two blue and one white) 3L on sale on Sunday. This is very rare opportunity to get hold of these.

These makes very good ferments and miso fermented in these crocks never have failed to amaze me💕 Honestly

If you can’t come on Sunday but desperate to have in, I will explore the way to ship them to u (uk only!)
Want to reserve? DM me!

常滑クロック、3甕在庫あります。ブルー2つと白が1つ。
味噌は本当に深い味わいになりますよ。糠床容器にも最適！
お勧めしてもしきれないくらい惚れ込んでます。
数に限りがあるので予約受け付けま😊(dmください)
来れない方でどうしてもという方は、郵送手段も探します。

Back in august I was in Japan for two weeks mainly (or almost solely) due to family engagements. It was first time in nearly three years and I was so happy to be able to see my own parents and support my mum to look after my dad who has dementia.
Inevitably my schedule was absolutely packed that I could hardly see any of my friends …..
Nevertheless, not bad I managed to bring these back to U.K. 😊

What is more appropriate to accompany our pink shio-koji (the colour is from medicinal red koji) than salt-pickled cherry blossoms 🌸
I hand-picked them last year and they have been kept in my pantry shelf all year😅
As cherry blossom season is around the corner (it needs to be a particular variety), I can use them generously 😅

What an aroma !! I think I am going to make this my regular 🌸
#桜の塩漬け