Interview with Robin Sherriff, owner of the Koji Kitchen

Updated: Aug 31

Taste Magazine had the fantastic opportunity to sit down and interview Robin Sherriff from the Koji Kitchen. A newly established company which focuses on koji production, Sherriff likes to experiment in the kitchen and create different flavours of miso from the koji.



Sherriff has an MSc in Gastronomy and was fortunate to travel to Japan before covid to learn about koji. During the pandemic he established The Koji Kitchen in Edinburgh to further educate and teach people about the importance of fermentation and how we can use that knowledge to bring back autonomy over our own food system.


Taste Magazine was fortunate to sample several of Sherriff’s miso including an apricot one, a red miso and a white miso during the interview where we also filmed his ‘Miso e Pepe’ recipe which is in our print magazine!



Tell me about the Koji Kitchen.


I launched this company in November last year. I have just been growing since then. I am a big believer in lean methodology. So just keep everything as small as possible rather than over expanding because during the conceptual phase last year, I saw all these businesses that had over-extended just fall apart, so I [thought], I am not going to do that.


What is the process behind creating koji?


The process of making koji is quite a complex process but effectively, you have got steamed cooked rice or some other source, then you inoculate with koji kin, which is koji spores essentially. It is mould growth. So, you have got that as a source of fermentation. The mould is trying to flower essentially, to bloom. But before it can bloom it has to convert all of the sugars and the proteins into fuel that it can use and so it releases and seeds out enzymes into the rice itself. Then that breaks down starchy things into sugar and breaks down your proteins into peptides and then amino acids. Amino acids are an MSG, that is what gives you that umami flavour.


When you’re making a miso, or a soy sauce or even a tamari, pretty much any koji based fermentation, you add that into your cooked soy beans or whatever other protein source you’re looking for along with salt, and then you have a very interesting dance of fermentation that proceeds. At the start, you will get an inoculation just from lactic acid bacteria. Or wherever you’re making it, although industrially they do add lactobacillus. And lactobacillus is your classic fermenter, that’s what makes kimchi tangy, that’s what made sauerkraut acidic. So that jumps in first. And what that does, is it drops the pH and creates a safe environment. From that point you cannot get any pathogens settling in.


Then everything else can start to go to work. Yeasts that are fine with acids, they can start to jump in, they can start to break things down, create things like alcohols which is quite interesting. Your enzymatic load that is brought in by the koji, that can start to work in a safe environment. And again, that breaks down your proteins, that breaks down your sugars, and that’s when you can get really complex flavours pulled out. So over time those enzymes will keep acting, they will keep going. Which is brilliant.



Can you tell me about the miso you currently make yourself?


So, as you get older, you will get red misos, and the younger they are, they will be called white misos. The predominant difference there is your ratio of koji rice to soybeans. With a red miso, these really far aged misos, you will get far more soy beans, far less koji rice, and more salt. For your white misos, there’s far more koji rice, less soybeans, and less salt. What you end up with white misos is they are really sweet, they have some umami to them. But they are not super complex. It is not something that you will be thinking about for 10 days afterwards. Whereas the older you get and the higher soy/bean ratio, the more complexity you can pull out.


One of the things when I am discussing things is that this is a gross super over-simplification, there are ten thousand types of miso you know. And all of the ones [in my kitchen] are gluten free. And pretty much every allergen free.


Where do you source your ingredients?


I use an Italian short grain varietal rice. It’s not japonica: the reason I have chosen that is it is quite hard to get Japanese rice here. Not only as a price inhibitor, but it is quite hard to find organic Japanese rice. You can get it in very small pouches but [not] on bulk. So there is that practical issue and then there is the fact I am trying to keep it as low air miles as possible. I use this organic short grain rice from Northern Italy, which works very well with the koji.


Just to give you a brief overview of rice: rice is all polished to remove the outer husk of it, and the lower you polish it, the higher quality in general.


Now, beans. Right now, I am using a Chinese organic supplier which I am happy with, however I am going to move over to an Italian producer as well for similar reasons and also there is more consistent quality. What I found with the Chinese bean supplier that I have been using is that sometimes you get really tiny beans, sometimes you get huge ones. When I am making something which I don’t know how it is going taste until three months later, I want to know that it is consistent when it goes in.


Then all my spores come from Koichi Higuchi of Higuchi Matsunosuke Shoten Co. He’s one of seven spore producers in Japan, and he’s from Southern Osaka.


How often do you need the spore delivery?


Spores are incredibly stable. When you get them sent out, they are incredibly dry and incredibly low moisture. They are packed in such a way that there is no moisture, there is no other microbial activity. So, they have got something crazy, like a 24-month shelf life, but I restock roughly every 6 months. A little bit of koji spores goes a very long way.


You also create recipes; how do you go about creating a vegan or vegetarian version of a meat dish?


Now when you are thinking about building a dish into something vegan, a lot of people try to sub like for like. ‘We don’t have this meat thing so we will put in this pretend soy meat instead.’ And [they] think it will taste the same, but it will not. You have to rebuild flavours from the ground up. With parmesan, which is this super complex heavily fermented aged thing, you cannot just say ‘let’s slam in some miso and everything will be okay’. Miso does not have any butyric acids which is what gives parmesan that funk. You have to make up that acidity by adding lemon, citron peppercorn, adding in extra level and depth.




What’s your favourite recipe to make with the koji spores?


There are so many and it changes from day to day. My old standard is always just saying ‘shio koji bruschetta’ because it makes people’s eyes light up, it really changes people’s minds. I think my favourite one at the moment are these different variants of pickling beds. You can make different ones that include boiled rice and you can make a thing called a Sagohachi pickling bed which means 3-5-8. So that is just the ratios of koji, water and salt mixed into a paste. Then you can bury vegetables in that and essentially ferment them to the same level that it would take two weeks of lacto-fermentation in a couple of hours. So my favourite is Japanese pickles or quite small pickling pickles. One slice through them in a pickling bed for half an hour; I just love it, it is so fresh, it is so good. So just a big old plate of pickles on a bed of rice, that is my favourite right now probably.


What are your top three tips for creating recipes with or without koji?


Creating recipes with koji is to understand that koji is not an ingredient, it is an engine. So because people are talking about [koji] more and more - I see chefs adding in koji rice and then cooking it straight away. If you are cooking it straight away, you are denaturing those enzymes. Yes, it is a dark, woodsy, mushroom, chestnut aroma, but the point is the reason you are using this is not to add some sort of chestnut flavour, you need this for the enzymatic action it brings. So, my advice would always be: understand the fundamentals, understand that it is an engine and that it is not the final product. So again, make yourself some shio koji, play with it. See how far it can go. Even if you make a shio koji and then you mix in chocolate and whisk that through for a little while, you can make some incredible stuff with it.


Now to answer the second question of recipes in general. I would say I subscribe to two main schools of thought. I really like David Chang and his theory of flavour. He talks about it more from the side of flavour memories and the idea that you can access certain memories through different tastes. I view it more [as] all flavours are constituent parts of how our taste perception works. So, if you can break down what kind of flavour you are trying to get into its fundamental parts, you can rebuild that out of different materials. So that would be my approach to flavour creation. Also, I subscribe to Sandor Katz [who] is an incredible fermentation author. I have got every book that he has ever written. The Art of Fermentation, Fermentation as Metaphor. He has this real attitude of just learn a little bit about the culture, learn about the history. Get in a kitchen. Go wild. Make mistakes. It will be fine. I very much subscribe to that too. So, I would say that two-step process of have a big idea, get it wrong lots. Think about it analytically. Then rebuild it from a flavour perspective.


You have an MSc in gastronomy. Do you not think that is easier for you do though?


Many, many years ago I studied chemistry and then I worked in biology for a little while before I went into food full time. So having that under my belt does allow me some level of studied practiced analytical tools, and analytical thinking. However, I don’t know. You don’t need the intense level of analysis. I use these scientific and analytical skills for my professional production, however when it is a recipe development, I think anyone can do it really.



You sell some products and you have a make your own miso kit. What is your route to market strategy?


This is a technique I have developed and I am sure other people have used the same strategy but I have never read it in so many words. The way I view it is a three-prong strategy. I use retail, direct customer and restaurants. I have tried to approach these all and view it as three pillars and they all look after each other. So last November [time]. Everything is closed, there are no retailers, very few restaurants. I really had to lean on the direct customer model. That involved building a nice social profile, selling through e-commerce, so either through my website or amazon. That was my direct customer strategy.


Then you can approach restaurants and work with chefs directly and have them use koji in their recipes. You can approach retailers and retailers can sell [it] on the shelves. The reason using all three of these is because your direct customer might own a retailer or they might be a chef, and then they will approach you, ‘can I get this product?’ Or someone could go into their local retailer and say ‘what is this?’ Then they investigate or they go into the restaurant and [think] ‘koji? what is that?’ Then they google.


I have done some good work with SEO so I am the first pop-up on amazon. All of these pillars drive towards each other and they support each other so it is quite a useful and effective growth strategy.


Where did your interest come from in creating koji? You have had all this experience with Bonnie Sauce Co, Fudge Kitchen, etc. Why the specific interest in fermentation?


What was really nice is I have had all this food experience, and then I went to study this systems theory Masters in food.


That was 2018/19. Systems theory has this wonderful way of drawing all these distant parts of this system and then pulling it together and crystallising it into one thing. Not only did I learn that in an abstract perspective towards the degree, but you can apply this thinking to yourself in your life. So, all of these different miasmic tentacles of my own existence, they were sort of dragged together and it was like ‘what is it I really care about? What is it I like?’


I like being able to get really nerdy and be able to really get into the science of [food]. I like that. I like being able to just knock about in the kitchen and create stuff. That’s cool. I like talking to people. I like doing brand marketing and being in person, talking to folk. So I can do all these things, what else do I really care about? Something I deeply care about is the food system.


I think our food system is completely humped at the moment. It doesn’t work. As it stands, 98% of the calories in this country go through 7 companies. That is it. Probably under 100 people have control over 98% of the calories that are consumed in this country. That is a broken system. That doesn’t work.


I think that little facet of fermentation is how you deconstruct this enormous leviathan that is the food system.


Then during my masters I convinced the university to send me to Japan to live there to study my thesis on Japanese whisky. And the philosophy of Japanese whisky. It became a comparative study between Japanese whisky and Scottish whisky and it was fascinating. I got to travel up and down Japan, and meet lots of different whisky distillers, go to different food and drink shows. I [thought] I should really do my cultural due diligence and learn about Saki and Shochu, their Japanese native alcohol. I went to Saki breweries, and I lived around the corner from a Saki brewery. I went round and they showed me this really old wooden room in what was otherwise a fairly modern brewery, and it was all these mouldy rice in trays. It smelt amazing and he was telling me about koji and I was like okay. This is a little nugget in the brain.


So I came back and I researched sake, researched koji and then at the start of 2020, I went back to Japan. I went back to Japan to try and learn more about koji specifically. And then covid hit, so I came back and then I [thought] ‘You found out the things you like, you found out the target and how you want to change the world and now you got the tools to do it. Let’s start a company’.


So yes, koji is my route to deconstructing the entire global food system and making myself happy one grain of rice at a time.


How has that been starting a business during the pandemic?


Actually, it allowed more space during research and development. And you have to take the wins where they are and very quickly I [thought] I cannot do this fast growth thing. You cannot use your accelerator tools that you know how to use. Whilst I can do e-commerce, e-marketing, social, my secret sauce is doing promotional events. I have done it for a very long time. But I cannot utilise that, so I will go down this slow growth model, really tweak the brand.


You expressed interest at one point in doing sake craft beer, is that still part of the plan?


Yes, big time! That was one of the initial plans. There was a lot of people interested in funding pre-pandemic. Now, I am viewing it as a blessing in disguise because sake will be the end goal. We will get there eventually. But this would mean if I build [the company] this way and I have a successful own koji and miso company behind me, it would mean that I take on less investment and I would maintain more control over the business.


What’s been you biggest successes and issues?


Well issues are in obviously just the enormous challenge of getting this off the ground and trying to get it into a commercial product. All of those initial business challenges: jumping through the health and safety loops. Convincing random health officers that mouldy rice is fine. Quite a difficult sell in Scotland.


I actually think the most difficult one is finding packing suppliers. I just want compostable packing that will fit 300g of koji, but I have had to go through six different suppliers. So that has been my biggest bug bear.


Biggest successes. Loads. I have really liked working with some chefs who I wish I could name. I have really liked being able to travel round the country and speak to different producers and retailers and spread the good word of koji. I was very happy when I got my first retailer in Europe. I got River Run Ferments in Ireland.


What are your personal goals for the company?


Phase 1 was just to bring out commercially dry available koji. Penetrate the market to some kind of degree which I have done, and then increase that market share. Second phase was to move into things like miso paste, maybe shio koji ready to buy. These value-added products. And then phase 3 of the business is to push into sake. This is [over] 3-5 years. It is quite a long time, and I suppose personally what I want to extract out of the business is for it to allow me do the things I like to do. Which is research food, chat to cool food professionals. Eat awesome food, travel to Japan now and then. I don’t have very complex demands over the world.


Do you have anything else to add?


I’m really excited about some Korean fermentation buckets that I should be getting in the next couple of months. They are great, they are called crazy Korean buckets, [for] my test misos: badger pea, black bean soy and apricot miso.



Robin Sherriff owns Koji Kitchen and currently offers classes in collaboration with other food enthusiasts on fermenting.

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