Yesterday I was doing something very ordinary. I was walking through Hanos with my mother while she did her groceries. My self appointed job on these trips is to wander around, read labels and quietly hunt for curiosities on the shelves.

Most of the time I see the usual suspects. The big plastic bottles. Familiar logos. The global brands that follow you around wherever you go.

Then my eye stopped.

In the soy sauce section I expected to see Kikkoman and its friends. Instead I saw something that looked very un Dutch on the outside and very Dutch on the label.

Tomasu. Dutch soy sauce. Made in Rotterdam.

At first I thought it might be some kind of fusion gimmick. A nice design project with Japanese letters to make it look exotic. But then a small sentence on the bottle woke me up properly.

The only micro brewed soy sauce in Europe.

Right there between the pallets and the fluorescent light in a wholesale store in the Netherlands.

I turned the bottle in my hand, felt the weight of it and realised there was a much bigger story inside.

Soy sauce with Dutch terroir

When you live in Japan, soy sauce becomes part of the daily background. It is as normal as salt. There are cheap soy sauces and beautiful regional ones. Old family breweries in small towns. Fancy labels with gold print. You see it everywhere.

So the idea that somewhere in Europe someone decided to grow their own soybeans in Dutch soil and make a soy sauce with local character feels almost crazy. In a good way.

Tomasu is not a marketing name pulled from a random generator. It is simply the Japanese pronunciation of Thomas, the founder who grew up in Rotterdam. He did not just decide to import some barrels and slap a Dutch label on them. He started in the dirt.

The soybeans for Tomasu grow in the Hoeksche Waard, about half an hour south of Rotterdam. The wheat comes from the same area. So the base of this soy sauce is not anonymous commodity soy from somewhere far away. It is literally Dutch clay, Dutch rain, Dutch seasons that you are tasting.

To that they add water and a beautiful grey sea salt from the Atlantic coast of France. Nothing refined and perfectly white. A coarse, mineral rich salt that keeps a bit of the ocean in it.

Then the magic begins.

A house microbe and a lot of patience

Every fermentation story has a hero you will never see with your eyes.

In Tomasu that hero is their own strain of Aspergillus oryzae, the fungus that turns soybeans and wheat into koji and unlocks all the deep umami. Many Asian food traditions work with koji, from miso to sake to soy sauce. It is one of those quiet miracles of the culinary world.

Instead of buying a generic starter, Tomasu uses its own house culture. That means the micro life involved in each batch is part of what makes the taste unique. It is not just the beans and the salt. It is the invisible world that lives on them.

Once the cooked soybeans and roasted wheat are inoculated with this koji they become a living mash. Add salt and water and you get what is called moromi, a thick paste that will sit and ferment while the microbes work away slowly.

Now imagine what most industrial soy sauce production looks like. Speed. Volume. Efficiency. There is a method where you can break down defatted soy with acid in a few days, then add colours and flavours and you have something that legally qualifies as soy sauce.

Tomasu swings in the opposite direction.

The moromi goes into old American white oak barrels that previously held whisky in Scotland. Some of those barrels have already lived a long life in distilleries before they ever see a drop of soy mash. They are between twenty five and fifty years old.

And then the waiting starts.

At least two years. Often closer to three. In a climate that is not Japan, but the windy, sometimes cold, sometimes humid environment of the Netherlands. The barrels breathe. The microbes eat and transform. The wood gives a little of its past life to this new one.

When you finally pour that soy sauce into a bottle, you are not just bottling a condiment. You are bottling time.

From plastic bottle to single barrel

Standing there at Hanos with a Tomasu bottle in my hand, the contrast to the big plastic Kikkoman containers could not be bigger.

One side is global standardisation. Reliable and familiar. A product that tastes the same whether you are in Tokyo or Amsterdam.

On the other side is one barrel at a time. A soy sauce that carries the fingerprint of one field, one microbe culture and one old whisky cask. The difference is the same difference you feel between sliced factory bread and a slowly fermented sourdough that someone fed and cared for every day.

Of course this has a price.

A small 100 millilitre bottle of Tomasu costs about the same as a decent bottle of wine. This is not the soy sauce you pour recklessly all over your rice. It is the one you bring to the table like a special oil or a good balsamic vinegar. A few drops at the right moment.

That price is not just for the label. You pay for two to three years of barrel time. For local farming. For someone who decided that soy sauce deserves the same level of respect and slowness as good cheese, whisky or wine.

Not just salty brown liquid

There are different faces of Tomasu.

The original soy sauce sticks to the pure base. Soybeans, wheat, water, salt, koji. Nothing more. The long time in the whisky barrels gives it a deep, layered flavour that is salty but also gently sweet, with a soft echo of the oak.

Then there is a sweet version that takes the original and adds sugar from local sugar beets. It becomes thicker and coats food in a way that reminds you a little of Indonesian ketjap, but more refined.

For those who like some fire there is a sweet spicy version, made with Madame Jeanette peppers. If you have lived in the Netherlands you probably know this chilli from Surinamese and Caribbean food. It gives a bright, fruity heat that does not scream but sings.

This is where it gets interesting for me. A Dutch soy sauce that pulls ingredients and influences together from Japan, the Dutch polders, the French coast and Surinamese peppers. All in one bottle that feels strangely at home on a European table.

The brewery does not stop at soy sauce either. They make sambal from the leftovers of their sweet and spicy sauce. They develop special editions and collaborations that push soy sauce into areas you would not expect, even into cocktails. Imagine a tiny dash of aged soy sauce in an espresso martini for depth. It sounds wrong until you taste it.

Soil to bottle as a quiet revolution

What I like about this whole story is not just the romantic image of wooden barrels and handwritten labels.

It is the decision to start from the soil. To treat soy sauce not as a cheap flavour bomb but as a product with terroir, just like wine or cheese. The taste starts with the health of the field. With how you treat the land and the plants that grow in it.

In a time where many people are completely disconnected from where their food comes from, a bottle like this is a small but powerful reminder. Even something as everyday as soy sauce can be a deeply local expression if you allow it to be.

There is also something very European and hopeful about this. Instead of trying to copy Japan perfectly, Tomasu embraces Rotterdam and the Dutch landscape. It respects the Japanese technique but lets the local reality shape the final result.

For me that is a beautiful metaphor for being an immigrant and a guest in different countries. You learn from traditions, but you let them grow roots in new soil. Something different and unexpected will come out of it.

From Hanos to your kitchen table

I did not plan to have a mini existential moment in the soy sauce aisle at Hanos with my mother. But this is what I love about paying attention. You think you are just walking through a warehouse filled with boxes, and suddenly you are holding a story in your hand.

If you ever see Tomasu on a shelf, pick up the bottle and read the label. Remember that what is inside has lived for years in an old whisky barrel, started its life in Dutch soil and carries the work of microbes you will never see.

Will it replace the big bottle of Kikkoman in your cupboard. Probably not. Each has its place. One is your everyday worker. The other is your small luxury, your special finishing touch when you want to honour a dish or a moment.

But the next time you pour soy sauce over something, whether you are in Europe or in Japan, you might remember that there is a quiet revolution happening in a field in the Hoeksche Waard.

And that somewhere in Rotterdam a fungus, some soybeans and an old whisky barrel are taking their time to create the next bottle.

If you enjoyed this story, let me know. I am curious how many of you have discovered small, obsessive food producers in the most unexpected supermarket corners. Maybe your next life changing ingredient is already waiting for you on a shelf, behind something you have seen a thousand times before.