Making L. reuteri yogurt is really a simple process, but it still trips up some people. Or they don’t understand what we are trying to achieve here, even believing that the benefits we seek can be achieved with conventional yogurt—no, not even close. Or that methods such as prolonged fermentation are unnecessary. So let’s list some of the tripping points to help avoid ending up with a liquid mess that fails to yield all the wonderful benefits of this microbe when restored to your microbiome.
I say “restored” because 96% of people have lost this microbe for a variety of reasons. (Take a look at your bowel flora analysis from Thryve, Viome, or Gut Zoomer, for instance, to see whether you have L. reuteri—you likely do not before consuming the yogurt.) Perhaps your mom lost this microbe and was thereby unable to provide it to you via passage through the birth canal and/or breastfeeding, or perhaps you were delivered by C-section and bottle-fed with little opportunity to obtain it. Or perhaps you took a course—or 5—of antibiotics for ear infections as a kid. Or you have been exposed to glyphosate that, while an herbicide, is also a potent antibiotic that kills off healthy microbial species. There are many reasons that the modern microbiome has been disrupted in the majority, perhaps all of us.
Recall that we ferment for an extended period of time: 36 hours, not the 4 hours of conventional yogurt making. L. reuteri doubles (1 microbe becomes 2, 2 becomes 4, 4 becomes 8, etc.) every 3 hours at 100 degrees F. Fermenting for 36 hours therefore permits 12 doublings, rather than the single doubling permitted by brief conventional fermentation. This is why we obtain greater than 200 billion CFUs (bacterial counts) per 1/2-cup serving. (Our last flow cytometry run yielded a live count of 262 billion.) We also add prebiotic fibers to the fermenting mix to both ensure greater microbial numbers, as well as thicken the end-result.
I have made well over 100 batches without a single failure, so I know that you can do it, too. And, if you join the discussions in our Undoctored Inner Circle website, you can add a number of other interesting fermentation projects that achieve effects such as shrinking your waist, deepening sleep, heightening your immune response, accelerating recovery after strenuous exercise, and reducing arthritis pain.
L. reuteri yogurt-making “Do’s”:
- Do choose dairy with no added ingredients, i.e., no added gellan gum, xanthan gum, carrageenan, etc. as this will cause too much separation into curds and whey.
- Do clean your utensils and jars/bowls with hot soapy water to minimize contaminants. Some people even heat their materials, e.g., in the oven, to kill any contaminants.
- Do begin by making a slurry of a couple tablespoons of yogurt from a prior batch or other source of bacteria (e.g, crushed Gastrus tablets, contents of one Osfortis capsule), a couple tablespoons of half-and-half or other liquid, 1-2 tablespoons prebiotic fiber; mix well. Only then add the remaining half-and-half. This prevents clumping of the prebiotic fiber.
- Do indeed ferment for 36 hours—no more, no less. The last 3 hours, for example, doubles the number of microbes, e.g., 130 billion becomes 260 billion—a considerable jump. Don’t listen to conventional yogurt makers who confuse what we are doing here with conventional yogurt-making: two very different things. (We are not actually making “yogurt” by the standard FDA definition; we are simply fermenting dairy–but it looks and tastes like yogurt so we call it “yogurt” even though it is much more powerful.) Ferment longer than 36 hours and the rate of microbial death begins to exceed the numbers obtained via doublings (likely due to competition for resources) and you can actually obtain fewer bacteria. Prolonged fermentation also maximally converts the lactose to lactic acid; people with lactose intolerance can typically eat the yogurt without any adverse effect. The drop in pH to 3.5, not the 10-fold less acidic pH of 4.5 of conventional yogurt, means that the casein beta A1 is at least partially denatured, disabling some of its immune-stimulating potential.
- Do verify the temperature of whatever device you are using to maintain the fermenting temperature, as not all devices are accurate. Also, some devices are pre-set for yogurt making but are set too high; if the device heats to 112 degrees F, for instance, it will kill L. reuteri, since this species dies starting at 109 degrees F or higher. Ideally, choose a fermenting device (yogurt maker, sous vide device, Instant Pot, etc.) that allows you to vary the temperature, as well as the time.
- Do store your yogurt in the refrigerator where it is generally fine for up to 4 weeks. You can also freeze the yogurt without killing the microbes. (It actually makes a delicious frozen yogurt; here’s a simple recipe for a Chocolate Frozen Yogurt, as shown in the photo above.)
- Do cover your yogurt lightly during fermentation to minimize fungal contamination, e.g., plastic wrap or a loosely-fitting lid.
L. reuteri yogurt-making “Don’ts”:
- Don’t pre-heat. If you choose a pasteurized dairy product, there is no need for pre-heating. Conventional yogurt-makers pre-heat because they typically start with a reduced fat milk and pre-heating improves the texture and mouthfeel of the end-result. We start with half-and-half with around 18% milk fat that yields a wonderful texture and mouthfeel—no need to pre-heat.
- Don’t stir the mixture while it is fermenting, as this increases separation.
- Don’t use a blender with your yogurt, as this kills the living microbes. While you may still obtain the oxytocin-provoking effect, you lose L. reuteri’s probiotic properties.
- Don’t put your fermentation setup near an air vent, as the high volume of air will cause fungal contamination.
- Don’t heat your end-result, i.e., don’t heat on a stove or stir into a hot mixture, as this kills the microbes.
I like to pour off the liquid whey after removing some of the curds, as this reduces whey’s potential to trigger insulin. Even better, filter through a coffee filter or cheesecloth placed into a colander; place the setup into a large bowl or pan and allow the whey to drip out over 4-6 hours, lightly covered. This yields a thicker Greek-style yogurt.
By the way, I’ve written a new book about the intestinal microbiome that goes far beyond any other book before it, packed with prescriptive strategies to achieve all sorts of health effects. Stay tuned. In the meantime, be sure to go wherever you get your podcasts and look for my new podcast, Defiant Health. (Available on Stitcher, Podchaser, Spotify, Amazon Music, iHeart Radio, and Podcast Addict. Waiting for approval on Pandora, Apple Podcasts, and a few others—yes, it’s that new.)