Six years ago I bolted an external thermostat onto a cheap slow cooker with electrical tape and hope. Last week I watched a jar of L. Reuteri yoghurt hit a perfect 37.7°C and hold it there for 36 hours without me touching a thing.
That gap — six years of it — is what this post is actually about.
Why Would Anyone Build Their Own Yoghurt Machine?
I've made over 140 litres of this yoghurt by now. L. Reuteri, the SIBO-targeted blend, B. Coagulans — the strains William Davis writes about in Super Gut.
Not for the taste. For what these specific strains actually do once you have enough of them established: they signal the brain via the Vagus nerve to release more oxytocin — not just the "feel-good" hormone, but what Davis calls the hormone of shape and body composition. It helps preserve muscle mass as we age, lowers cortisol, and by his own account measurably increases emotional intelligence and social connection.
A gut-muscle-brain axis. Not the usual gut-brain one.
As a pharmacist, that's the kind of claim I don't take at face value. I looked into the mechanism myself before I believed it. But the case holds up — and it depends on one unglamorous detail almost nobody mentions: you actually have to culture these strains at home, in the right conditions, for long enough. Store-bought yoghurt has two boring FDA-approved bacteria. It won't do this.
What Almost Every Yoghurt Maker on the Market Gets Wrong
If you've read the book, you've probably already tried. And you've probably already hit the same wall I did:
Temperature cap
Most machines top out around 30°C. SIBO SuperGut needs 41°C. B. Coagulans needs 49°C. The dial simply doesn't go there.
Duration cap
These strains need up to 36 hours, sometimes more. Most consumer timers stop at 8, or 24 if you're lucky.
Wide hysteresis
Even the machines that can hit the number and the duration don't hold it. The "target" temperature is really a range — sometimes 6-8°C wide. Close enough for supermarket yoghurt. Not close enough for one specific strain that needs a steady number for a day and a half.
Fiddly, risky controls
Tiny buttons, unlabeled combinations, a manual you re-read every single time. Watching the temperature creep past where it should be, stabbing two buttons at once trying to remember the combination that stops it.
And 36 hours later, you often get something thin and watery — with no log of what actually happened overnight, and no way to know which of the above caused it.
That was me, for years.
How I Actually Solved the Yoghurt Maker Conundrum
The first fix, back in 2020, was exactly as crude as it sounds: an off-the-shelf machine, gutted, with a bolted-on external thermostat and a separate timer. It worked, in the sense that it didn't not work. It also had no real safety net — the sensor wasn't waterproof, broke down over time, and a replacement gave constant error messages.
Several generations later, I stopped patching other people's appliances and built my own controller from scratch. Real electronics — its own board, a calibrated temperature sensor checked against a certified reference thermometer, solid-state relay heating, a proper display and knob. Not a modified stock timer.
The part that actually took the longest wasn't hitting the right temperature. It was everything around it:
Problem: running dry
The machine could start heating an empty pan and nobody would know until the batch was ruined.
Solution: it watches for the temperature climbing too fast — the tell that the water's run low — warns you, and shuts the heater off safely if it's not corrected.
Problem: power cuts
A dropped power supply mid-batch used to mean silently going cold, with no way to know until it was too late.
Solution: it remembers exactly where it was and picks up from there.
Problem: not knowing if it's on track
At hour 20 of 36, there was no way to check in without standing over it.
Solution: it texts you — when it starts, periodic updates, and the moment it's done. Or just glance at the screen, WiFi or not.
It also turned out to be useful for more than yoghurt. Same principle — hold a steady temperature for a set time — works for kimchi, kefir, sourdough, kombucha, tempeh. Anything that needs patience more than attention.
What If You're as Frustrated as I Was?
I'm calling it Richard de Laat's Culture Craft™ Yoghurt Machine — and I want to be upfront about what it is right now: a hand-built, small-batch prototype. Each unit assembled and individually tested, not mass-produced. It hasn't gone through the independent third-party certification a retail appliance would. Joining the waitlist means buying into where this project actually is, not a finished consumer product.
Next round is 10 machines. If you've been fighting the same wall I was — dial that won't go high enough, timer that won't run long enough, or just tired of guessing why last night's batch turned out thin — the full story, the specs, and the waitlist are on the Culture Craft Yoghurt Machine page.
No payment now. Just an email the moment the next 10 open up.
Let me know what you think.
