Some deliveries just make your week. A friend of ours just got back from the States and brought me something I'd been waiting on for a while: a fresh supply of Bacillus subtilis HU58.

If you've been following along, you know we've made Dr. Davis's SIBO yogurt religiously for three years now — the classic triple-strain version, a fresh batch every couple of weeks, and we genuinely love it. But the recipe has evolved, and I've finally got what I need to catch up.

Two bottles of HU58 B. subtilis beside a box of BioGaia Gastrus
The new third strain (HU58) next to my trusty BioGaia Gastrus.

#What actually changed

In his 2025 update, Dr. Davis swapped Bacillus coagulans for Bacillus subtilis HU58 as the third strain in the SIBO yogurt — joining L. reuteri and L. gasseri.

It's not a random tweak. HU58 is a hardy, spore-forming probiotic that tends to ferment more reliably than coagulans, and it brings a little more firepower to the gut: it produces a range of bacteriocins (natural antimicrobial compounds) and helps break down the biofilms that troublesome bacteria hide behind. For a yogurt built to push back SIBO, that's a meaningful upgrade.

I dig into the full reasoning and the updated method in The 2025 SIBO Yogurt Update.

#Why I'm a little nervous (and a lot excited)

Here's the honest part: we love the old recipe. Three years of thick, creamy, reliable batches makes you loyal, and swapping out a strain feels like messing with a good thing.

But the whole point of this yogurt is the gut benefit — and if HU58 is the stronger anti-SIBO player, I want it in the jar. I'm genuinely curious how it'll change the texture and the tang. B. coagulans gave us a lovely, mild set; I have no idea yet how HU58 compares once it's fermented.

#Getting ready

The good news: my core setup doesn't change — same sous-vide rig and Mason jars, same prebiotic fiber. The twist is that I'm running this as a two-part ferment, because HU58 (a Bacillus subtilis) likes gentler conditions than the Lactobacillus strains:

  • L. reuteri + L. gasseri together — my usual 106°F for 36 hours.
  • HU58 on its own — a cooler ~98.5°F (in the 90–100°F range) for 24 hours, right around body temperature, which suits the Bacillus better.

Then I combine the two at serving time. Fermenting the HU58 separately means it isn't competing with the Lactobacillus strains, and each gets the temperature and time it actually wants.

Mason jars in a sous vide water bath with the Anova cooker holding temperature
The setup's ready and waiting — the first HU58 batch goes in this week.

#Stay tuned

I'm making my first HU58 batch this week, and I'll report back with the full verdict: texture, taste, how it sets, and whether it earns a permanent spot in our rotation.

If you've already made the switch to HU58, I'd love to hear how it went for you. Either way — here's to the next batch. 🥛