Rebuild the microbiome with lost species – With yogurt from L. reuteri, L. gasseri, B. subtilis, B. infantis - SIBO yogurt

Updated on August 31, 2025

Recipe: Make SIBO yogurt yourself

Also suitable for people with lactose intolerance (see notes below).

Ingredients (for approx. 1 liter of yogurt)

• 4 capsules L. reuteri (each 5 billion KBE)

• 1 capsule L. gasseri (each 12 billion KBE)

• 2 capsules B. subtilis (each 3 billion KBE)

• 2 capsules B. infantis (each 1 billion KBE)

• 1 tbsp inulin (alternatively: GOS or XOS for fructose intolerance)

• 1 liter (organic) whole milk, 3.8% fat, ultra-high temperature treated and homogenized or UHT milk
  (The higher the fat content of the milk, the thicker the yogurt)

Note:

• 1 capsule L. reuteri, at least 5 × 10⁹ (5 billion) CFU (en)/KBE (de)
• CFU stands for colony forming units – in German, kolonie-bildende Einheiten (KBE). This unit indicates how many viable microorganisms are contained in a preparation.

Notes on milk choice and temperature

• Do not use fresh milk – it is not stable enough for the long fermentation times and is not sterile.

• Ideal is UHT milk (long-life, ultra-high temperature treated milk): sterile and ready to use.

• The milk should be at room temperature – alternatively, gently warm in a water bath to 38 °C (100 °F). Please avoid higher temperatures: from about 44 °C, the probiotic cultures are damaged or destroyed.

• Do not heat above 44 °C – at this temperature, the probiotic cultures are damaged or destroyed.

Preparation (first batch)

1. Open all 9 capsules and pour the powder into a small bowl.

2. Add 1 tbsp Inulin. For people with fructose intolerance, GOS or XOS are suitable alternatives.

3. Add 2 tbsp milk and stir thoroughly until no lumps remain.

4. Stir in the remaining milk and mix well.

5. Pour the mixture into a fermentation-suitable container (e.g., glass).

6. Place in the yogurt maker and ferment at 38 °C (100 °F) for 36 hours.

Subsequent batches

From the second batch onward, use 2 tbsp of yogurt from the previous batch as a starter. This also applies if the first yogurt is still thin or not perfectly set. Important: only use if it smells fresh, tastes mildly sour, and shows no signs of spoilage (no mold, no unusual discolorations, no pungent odor).

Ingredients per 1 liter of milk (subsequent batch):

• 2 tbsp yogurt from the previous batch

• 1 tbsp Inulin

• 1 liter of UHT milk or ultra-high temperature treated, homogenized whole milk

Here's how:

1. Add 2 tbsp of yogurt from the previous batch into a small bowl.

2. Add 1 tablespoon of inulin and 2 tablespoons of milk, stir until smooth with no lumps.

3. Stir in the remaining milk and mix well.

4. Pour the mixture into a glass and place it in the yogurt machine.

5. Let ferment at 38 °C (100 °F) for 36 hours.

Important note

• Inulin is the food for the cultures – add 1 tablespoon per liter of milk with each batch.

If you have questions, we are happy to assist you via email team@tramunquiero.com or via our contact form.

Why 36 hours?

The choice of this fermentation duration is scientifically based: L. reuteri requires about 3 hours per doubling. In 36 hours, there are 12 doubling cycles – this corresponds to exponential growth and a high concentration of probiotic active germs in the finished product. Additionally, the longer maturation stabilizes the lactic acids and makes the cultures particularly resilient.

!Important to note!

The first batch often does not succeed for many users. However, it should not be discarded. Instead, it is recommended to start a new batch with two tablespoons of the first batch. If this also does not succeed, please check the temperature of your yogurt machine. For devices where the temperature can be set precisely to the degree, the first attempt usually succeeds well.

Tips for perfect results

• The first batch is usually still a bit more liquid or grainy. Use 2 tablespoons of the previous batch as a starter for the next round – with each new batch, the consistency improves.
• More fat = thicker consistency: The higher the fat content of the milk, the creamier the yogurt becomes.
• The finished yogurt can be stored in the refrigerator for up to 9 days.

Recommended consumption:

Enjoy about half a cup (approx. 125 ml) of the yogurt daily – preferably regularly, ideally for breakfast or as a snack in between. This allows the contained microbes to develop optimally and sustainably support your microbiome.

Restart after 20 fermentations

A common question in fermentation with Limosilactobacillus reuteri is: How often can you reuse a yogurt starter before you need a fresh starter culture? Dr. William Davis recommends in his book Super Gut (2022) not to reproduce a fermented Reuteri yogurt continuously for more than 20 generations (or batches). But is this number scientifically justified? And why exactly 20, not 10, not 50?

What happens during re-culturing?

Once you have made a Reuteri yogurt, you can use it as a starter for the next batch. This transfers live bacteria from the finished product into a new nutrient solution (e.g., milk or plant-based alternatives). This is ecological, saves capsules, and is often done in practice.

However, repeated re-culturing leads to a biological problem:
Microbial drift.

Microbial drift – how cultures change

With each transfer, the composition and properties of a bacterial culture can gradually change. Reasons for this are:

• Spontaneous mutations during cell division (especially with high turnover in warm environments)
• Selection of certain subpopulations (e.g., faster growers displace slower ones)
• Contamination by unwanted microbes from the environment (e.g., airborne germs, kitchen microflora)
• Nutrient-related adaptations (bacteria "get used" to certain milk species and change their metabolism)

The result: After several generations, it is no longer guaranteed that the same bacterial species, or at least the same physiologically active variant, is present in the yogurt as at the beginning.

Why Dr. Davis recommends 20 generations

Dr. William Davis originally developed the L. reuteri yogurt method for his readers to specifically harness certain health benefits (e.g., oxytocin release, better sleep, skin improvement). In this context, he writes that an approach "works reliably for about 20 generations" before a new starter culture from a capsule should be used (Davis, 2022).

This is not based on systematic lab tests but on practical experience with fermentation and reports from his community.

"After about 20 generations of re-use, your yogurt may lose potency or fail to ferment reliably. At that point, use a fresh capsule again as starter."
— Super Gut, Dr. William Davis, 2022

He justifies the number pragmatically: After about 20 times of re-culturing, the risk increases that undesirable changes become noticeable, such as thinner consistency, altered aroma, or reduced health effects.

Are there scientific studies on this?

Concrete scientific studies specifically on L. reuteri yogurt over 20 fermentation cycles do not yet exist. However, there is research on the stability of lactic acid bacteria over multiple passages:

• In food microbiology, it is generally accepted that genetic changes can occur after 5–30 generations, depending on species, temperature, medium, and hygiene (Giraffa et al., 2008).
• Fermentation studies with Lactobacillus delbrueckii and Streptococcus thermophilus show that after about 10–25 generations, a change in fermentation performance (e.g., lower acidity, different aroma) can occur (O’Sullivan et al., 2002).
• It is specifically known for Lactobacillus reuteri that its probiotic properties can vary greatly depending on subtype, isolate, and environmental conditions (Walter et al., 2011).

These data suggest: 20 generations is a conservative, sensible guideline to preserve the integrity of the culture – especially if you want to maintain the health effects (e.g., oxytocin production).

Conclusion: 20 generations as a practical compromise

Whether 20 is the "magic number" cannot be scientifically determined exactly. But:

• Throwing away fewer than 10 batches is usually unnecessary.
• Producing more than 30 batches increases the risk of mutations or contamination.
• 20 batches correspond to about 5–10 months of use (depending on consumption), a good period for a fresh start.

Recommendation for practice

After a maximum of 20 yogurt batches, a new start with fresh starter culture from capsules should be made, especially if you want to specifically use L. reuteri as a "Lost Species" for your microbiome.

Daily benefits

Lactobacillus gasseri

• Weight regulation: Studies show that certain L. gasseri strains can reduce belly fat and body weight (Kadooka et al. 2010).

• Immune system: Supports the mucosal barrier in the gut and reduces inflammatory processes (Usman & Hosono 1999).

• Gut health: Promotes the balance between beneficial and harmful germs, can alleviate symptoms of irritable bowel syndrome and diarrhea (Ljungh & Wadström 2006).

• Hormonal effects: Some studies suggest that L. gasseri can stabilize the vaginal microbiome in women and prevent infections (Mikolajczyk & Bode 2012).

Bacillus subtilis

• Spore former: Especially resistant to stomach acid, reliably reaches the intestine.

• Immune system: Promotes the production of antimicrobial peptides and thus supports the defense against pathogens (Hong et al. 2005).

• Gut barrier: Improves the integrity of the intestinal mucosa and reduces the risk of "Leaky Gut" (Elshaghabee et al. 2017).

• Digestion: Produces enzymes (e.g., amylases, proteases) that facilitate the breakdown of food.

• Probiotic use: Has been consumed for decades in Japan in fermented soy products ("Natto") and is considered safe.

Bifidobacterium infantis (B. longum subsp. infantis)

Bifidobacterium infantis is now taxonomically classified as Bifidobacterium longum subsp. infantis, a subspecies of B. longum, but in research and everyday use it is usually shortened to B. infantis.

• Infant microbiome: One of the key early gut colonizers in breastfed infants, specialized in breaking down human milk oligosaccharides (Underwood et al. 2015).

• Anti-inflammatory: Lowers systemic inflammatory markers and is associated with reduced symptoms in irritable bowel syndrome patients (Whorwell et al. 2006).

• Gut barrier and immune system: Promotes mucus production in the gut and modulates the immune system by reducing inflammatory T-cell responses (O’Mahony et al. 2005).

• Psychobiotic: There is evidence of a positive effect on depression and anxiety disorders through influence on the gut-brain axis (Desbonnet et al. 2008).

Sources

• Kadooka Y. et al. (2010). Eur J Clin Nutr.

• Usman & Hosono (1999). J Dairy Sci.

• Ljungh & Wadström (2006). Microbes Infect.

• Mikolajczyk & Bode (2012). Benef Microbes.

• Hong HA. et al. (2005). Trends Microbiol.

• Elshaghabee FMF. et al. (2017). Front Microbiol.

• Underwood MA. et al. (2015). Clin Perinatol.

• Whorwell PJ. et al. (2006). Am J Gastroenterol.

• O’Mahony L. et al. (2005). Gastroenterology.

• Desbonnet L. et al. (2008). Neuroscience.