Garlic Mustard Tea

Herb-infused fermented garlic mustard tea with black currant leaf oil – applying ancient Russian techniques to wild herbs.

Back in the summer of 2013 our half Finnish, half Swedish head of R&D, Markus, was working on an old recipe he had stumbled upon. His Finnish neighbour told him how his ancestors made tea from fireweed in Russia and Finland. He was very intrigued by the story and started researching. It didn’t take long until he stumbled upon the Koporye tea. It was a Russian export that fooled almost everyone, because the fireweed tea tasted quite similar to the real thing. He then picked a small bag of fireweed leaves and did some trials. The result was fascinating. It really had some potential. But then the season ended. We met with Josh Evans from Nordic food lab, and found out that they also did tests on different tea making techniques in their lab.


In the summer of 2014, we started working together on the tea project. We tested more than twenty different techniques and found two that we really liked. We started to use these techniques with numerous wild herbs and focused on perfecting it. It was really mind blowing to witness the transformation of the green and bright leaves turning into a dark and complex broth, just by applying this quite simple technique.

The fireweed tea turned out great that season, and we did small batches with other herbs as well.

We made tea from sweet cicely flowers and tansy leaves. They really tasted like shit. The smell of the tansy leaves is one of the best and most amazing scents, but it turned out overpoweringly bitter. It was depressing for a while, but we then realized the result of this process couldn’t be predicted. We then tasted the garlic mustard tea and became happy again. It was so fucking good! By just adding a bit of sea salt, it turned into something like a complex Japanese broth, with a slight acidity from the fermentation. We were so excited about it, but only made enough to serve ten (very lucky) guests. The season had already come to its end, so we had to wait a whole year to do it again.

Now in the summer of 2015 we made a shitload of this stuff. So hopefully some of you will get a chance to taste it during the winter.


This is how we did it:

Making a cup of tea from scratch

You will need:

– Half withered leaves from fireweed or garlic mustard

– 2 plastic boxes that fits into each other


Start by rolling the leaves between your palms with some pressure. The leaves should be bruised and it should release some juices. When all the leaves are crushed, it goes in a container with a lot of air between the leaves. I stir them around once in a while just to get them exposed to the oxygen. After 6 hours, it’s done.


Put the leaves into a plastic container with another one on top of the leaves with a weight inside, to give some pressure.

It should be at ambient temperature. If you are making a steamed tea, it should be fermented for two days. For roasted tea it is three days.


Put the leaves in a 2,5 cm layer in gastro pans. Steam it for 1 minute at 90°C, and dry it until it is 95% dry. Seal in vacuum bags with some remaining air in it. Freeze it to make it stay fragrant for longer.



Put the leaves in a 2,5 cm layer in gastro pans. Roast it at 150 °C, while stirring once in a while and breaking up the lumps. When the tea is almost completely dried and the leaves are getting golden, it is done. Seal in vacuum bags with some remaining air in it. Freeze it to make it stay fragrant and tasty for longer.


Brew the tea at 96°C in filtered water. Let it infuse for four minutes, strain and serve. Dosage is different depending on what herb youre using, and what concentration you´re after.

This is how we make our tea. You can experiment with different methods of oxidation to get different results.

I suggest that you start making it this way, because it works really well. Then you can save three years of testing for yourselves. It is also a very interesting ingredient for cooking. Please tell us how its works out!

Herb-infused fermented garlic mustard tea with black currant leaf oil

You will need:

– Roasted garlic mustard tea

– A pot full of different herbs like mint, hip rose, geranium, lemon verbena, angelica and cat nip

– Black currant leaf oil


Brew your tea, and strain it. Heat it to 78°C and pour it into the pot with the herbs. Let it infuse for one minute.

Pour it into heated cups with 7 drops of black currant leaf oil inside.




Nicolai Nørregaard

Nicolai Nørregaard

Head Chef & Partner, Kadeau

The Kadeau project is much more than a restaurant: It’s a love affair with that special piece of nature out there in the Baltic, it’s a friendship-based company and it’s local food loving patriots fighting for jobs and recognition of the place we come from.

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