Dr. Johnny Drain has spent the past decade being the secret weapon of many of the world's Michelin-starred and 50 Best restaurants and bars. He is a fermenter, cook, and scientist who has pioneered the use of fermentation to turn food waste and by-products into delicious things to eat and drink.
His first book, Adventures in Fermentation, diving into the science of fermentation and gut health, and charting his journey through the world's best kitchens, releases in the U.S. on December 2, 2025 (it’s out already in the U.K. and other markets, and digitally). You can find him on Instagram here.
Heeeeeere’s Johnny:
There’s a food challenge that’s made the rounds on social media in recent years—the “30 different plants a week” rule. It got flavour freaks, fermentation nerds, and gut health nuts excited, not to mention busy in their kitchens. Maybe you’ve heard about it?
Maybe you’ve already got a note on your phone tallying up the chia seeds in your granola and the pine nuts in your pesto. Or maybe you rolled your eyes at the idea and carried on kimchi-ing. Now, to be clear: the heart of the message is sound. Plant diversity is good for your gut. A varied diet tends to be higher in fibre and full of phytochemicals that feed both you and the trillions of microbes that call your body home.
But that number—30—less so. It originated from a single survey question in the American Gut Project: a simple comparison between people who said they ate more than 30 different plants in a week and those who ate fewer than 10. The more varied group had more diverse gut microbiomes, but it’s not possible to say it was because of the plants, or how much of each they ate. It’s not that the study was bad. It’s just that that one question, and the findings based on it, are limited. But the number caught on—and here we are.
Still, I like the spirit of the idea. If it nudges us to eat a little more colour, a few more beans, an extra segment of dark chocolate—well, that’s only a good thing. I even took it as a challenge while writing my book, Adventures in Fermentation: could I cram 30 plant-based ingredients into a single ferment? A single jar that, symbolically at least, ticks the “30 a week” box. The result, a 30-ingredient kraut, is a riot of flavour, colour, and microbial life.
It’s a deep purple-red hue thanks to the inclusion of red cabbage and beet, with a kick courtesy of lots of garlic, ginger, and two types of chilli, and nuttiness and complexity from the inclusion of miso, sesame seeds, fenugreek and flax seeds. Once fermented, this kraut lives in my fridge where, in its steady, relatively unchanging state, it’s an ingredient I can build meals, snacks or sides around.
Cheese melts: Two slabs of sourdough, a generous handful of grated comté (or other hard cheese), and a scoop of this kraut sandwiched between. Toasted until the cheese oozes. Fermented, crunchy, gooey heaven.
The five-minute orzo lunch: I toss al dente orzo with olive oil, a splash of vinegar, and a few spoons of the kraut. Stir, and that’s it. 5 minutes from the time you drop your orzo into boiling water. A weekday lunch that tastes like weekend brunch that someone else made.
On the side of everything: Eggs, soups, toast, grain bowls, cold chicken, leftover curry. There’s nothing this kraut doesn’t improve.
Pictured below: steamed rice, loaded with the crimson 30-ingredient kraut, a hunk of Ullapool hot-smoked salmon, gari (pickled ginger) and then a little drizzle of sesame oil and sesame seeds. Heaven!
Here’s the kraut in question, from my book Adventures in Fermentation:
30-Ingredient Gut-Boosting Kraut:
1 medium red cabbage (about 800 g), shredded
1 medium white cabbage (about 800 g), shredded
1 large carrot, grated
1 red pepper, thinly sliced or diced
1 green pepper, thinly sliced or diced
1 yellow pepper, thinly sliced or diced
1 apple, grated
1 pear, grated
10 red radishes, cut lengthways in quarters
1⁄2 of a daikon, cut into long thin strips
4 small beetroots, washed and grated
1 broccoli stalk, diced
2 red onions, thinly sliced
4 spring onions, chopped
3 shallots, thinly sliced
4 cloves garlic, minced
1 piece fresh ginger (about 5cm), minced
1 stalk lemongrass, finely chopped
1 tablespoon chilli flakes
2 fresh chillies, finely chopped
2 teaspoons smoked paprika
1 teaspoon turmeric powder
1 teaspoon fenugreek powder
1 tablespoon flax seeds
1 tablespoon roasted sesame seeds
1 tablespoon white sesame seeds
Juice of 2 limes
4 tablespoons soy sauce
2 tablespoon miso paste
75 g sea salt
Method:
In a very large bowl, start combining the shredded red and white cabbage, grated carrot, thinly sliced peppers, grated apple and pear, broccoli stalk, radishes, daikon and beetroots.
Add the minced garlic, minced ginger, finely chopped lemongrass, thinly sliced red onions, chopped spring onions, thinly sliced shallots, chilli flakes, chopped fresh chillies, smoked paprika, turmeric powder, fenugreek powder, flax seeds, roasted sesame seeds and white sesame seeds. Mix well to combine. You may want to use gloves because there are chillies present.
In a small bowl, mix the lime juice, soy sauce, miso paste and sea salt, and pour this mixture over the vegetable mix.
Using clean or gloved hands, massage the liquid into the vegetables for about 5 minutes.
Transfer the vegetable mixture into clean, sterilized large glass jars. Press down firmly to remove any air pockets and ensure the vegetables are submerged in their own juices. Use a fermentation weight or a clean, smaller jar to weigh down the vegetables if necessary.
Leave about 2–3 cm of space at the top of the jar for expansion and expression of more liquid during fermentation.
Cover the jar with a clean cloth or a lid loosely screwed on to allow gases to escape. Place the jar in a cool, dark place at room temperature (about 18– 22 °C) for 1–2 weeks. Check the sauerkraut daily to ensure the vegetables remain submerged and to release any built-up gases.
The fermentation time can vary depending on the ambient temperature. Warmer temperatures will speed up fermentation, while cooler temperatures will slow it down.
After 1–2 weeks, taste the sauerkraut. If it has reached your desired level of tanginess, transfer the jar to the fridge to slow down the fermentation process. The sauerkraut will continue to develop flavour and can be stored for several months in the fridge.
Whether you're a seasoned fermenter or a total newbie, this kraut is a low-effort, high-reward way to pack colour, crunch, and microbial magic into your week. And if you happen to hit 30 plants along the way — even better.
Thanks, Johnny! We wholeheartedly endorse the concept of increasing the diversity of plants in our diets, and especially adding all manner of herbs and spices to our ferments. There’s lots of room for minimalism in food, and just as much space for maximalism. Sometimes more is more.