L. Gasseri FAQs

Reminder: L. Gasseri Superfood is fermented with prebiotic fiber. 

Click here to add our prebiotic fiber to your cart.


  • Is L. Gasseri Superfood a yogurt? No. L. Gasseri Superfood is not a yogurt, although it may look and taste like one, depending on the dairy used. (And for the same reason it may also look and taste very differently; like cheese, for example). L. Gasseri Superfood is a unique cultured dairy, made with completely different strains of bacteria than yogurt. These beneficial bacteria are called Lactobacillus Gasseri (L. Gasseri). Our L. Gasseri Superfood Starter was conceived as a method of introducing high quantities of L. Gasseri into your microbiome. The fermentation of the starter culture in dairy for 36 hours at a low temperature in the presence of prebiotic fiber (very different fermentation process than yogurt), enables the L. Gasseri to proliferate many times over, until there are hundreds of billions of live bacteria in the jar. The resulting concentrations of L. Gasseri are much higher than can be obtained from any currently available supplement or yogurt (including homemade ones) that we know of.
  • Why is the starter shipped without ice? See answer to "I live in a hot place. Is the starter still active after being shipped unrefrigerated in hot weather?"
  • I live in a hot place. Is the starter still active after being shipped unrefrigerated in hot weather? Yes. Our starters are designed to remain active for well over a week in non-refrigerated transit in warm weather, without the need for express shipping or ice. The formula and the packaging provide excellent protection for the live strains. For this reason, we use ambient shipping (which is also significantly less costly for the customer). The starters are kept cold in our warehouse until your order is ready for shipping, and when your order is shipped, we send you the tracking number so that you can see when it is due to arrive. Once received, the starter should be refrigerated (or frozen). 
  • Why do we add prebiotic fiber? As food for the L. Gasseri (which are living bacteria and need to eat), and for a thicker texture. (Get our prebiotic fiber here) 
  • Which strain of L. Gasseri does the starter contain? Our current L. Gasseri Superfood starter contains a high concentration of the BNR17 strain. One sachet of our starter is sufficient to ferment 1 quart of dairy. There are 4 such sachets in each pouch. Once you’ve made your first batch, you can use some of it to re-ferment subsequent batches. Over the fermentation period of 36 hours at 100 F, the L. Gasseri count doubles every 3 hours (12 doublings), resulting in a very high and beneficial final count. See our research
  • Which dairy should I use? 
    • For a very rich and vey thick end-product: 1 quart of half and half (ultra-pasteurized or heated to 195°F for 10 minutes and cooled, preferably organic, without additives).
    • For a rich and thick end-product: 2 cups of half and half + 2 cups of 2% or whole milk (ultra-pasteurized or heated to 195°F for 10 minutes and cooled, preferably organic, without additives).
    • For a fairly rich end-product: 1 quart of whole milk or 2% milk (ultra-pasteurized or heated to 195°F for 10 minutes and cooled, preferably organic, without additives). 
    • Why ultra-pasteurized? Because ultra-pasteurization, or heating the dairy and then cooling it, changes the dairy's composition in a way that helps it to thicken, and may also help prevent it separating into curds and whey. Most organic dairy is ultra-pasteurized. Use dairy without additives.
    • Why without additives? Because they interfere with the fermentation and increase separation into curds and whey
    • Dairy to avoid: low fat milk (too thin), cream only (too thick), and raw milk (it contains competing bacteria)
  • Can I use goat milk? Yes, but the result will be thin. Goat milk is also more prone to separation. 
  • Can I use raw milk? No. It contains competing bacteria.
  • Can I use non-dairy beverages? Our L. Gasseri Superfood was primarily designed for dairy. Fermentation of non-dairy beverages, while sometimes doable, is much trickier. See recipe here
  • Which device can I use? You'll need an appliance that can maintain a temperature of 100°F for 36 hours, and which can ideally hold at least one 1-quart jar. Best two options are:
        1. Sous-vide device. 
        2. Yogurt maker that can hold at least one 1-quart jar, with an adjustable time and temperature.
        • Other devices that might work: Instapot / slow cooker / brewing or kombucha warmer/heater - if these can be set to 100F for 36 hours, and ideally hold at least one 1-quart jar. Some of these appliances are automatically set to a higher temperature, which is too hot for the L. Reuteri to survive. The L. Reuteri bacteria love human body temperature. You may want to test your device with a cup of water and a thermometer before making your first batch. 
  • Do I have to ferment for 36 hours? Yes. The long, slow fermentation at a low temperature increases the L. Gasseri exponentially over the 36 hour period, and helps to create a thick, delicious final product.
  • Can I use a bowl for the fermentation, instead of a jar? You can, but a jar tends to work better (opt for 1-quart or 2-quart/half-gallon jars). The bacteria don't react well to air exposure. We therefore want to minimize the surface area that is exposed to air. A tall-ish jar will have a narrower rim than a bowl.
  • Why do I need to cover the jar with a loose lid? The bacteria don't react well to air exposure. The loose lid will minimize the surface area exposed to air and to condensation, while still allowing the mixture to expand and to release pressure. It's not enough to just close the appliance's cover -- this would still expose the bacteria to too much air inside the appliance. You need to place a loose lid on the jar itself.
  • What should the end-product be like? Thick, rich, and pleasantly tart, depending on the dairy you used. Separation is very common. 
  • How many times can I reculture? For as long as your batch comes out thick and pleasantly tart. Overall, batches should come out pretty similar to one another. When significant changes begin to occur (not tart enough or conversely, too pungent), although you're doing the same thing - go for a new sachet.
  • Can I make larger quantities? Absolutely! Save time by making larger quantities, with all the ingredients in proportion. For example, to make 2 quarts of L. Gasseri Superfood, just double the quantities: use 2 quarts of dairy, a 2-quart jar, 4 tablespoons of prebiotic powder, 2 sachets of L. Gasseri Superfood Starter (or 4 tablespoons of previously-made L. Gasseri Superfood), etc.
  • Can I use more than 1 sachet of starter culture? Only if you’re making larger quantities (see question on larger quantities). 
  • What are the starter's caloric/nutrition facts? These are printed on the back of the pouch. But overall, our starters contain such minuscule quantities of powder, that they are too tiny to have any impact on the end-product's caloric values. Our starters come in sachets of 1g - 3g of powder (depending on the starter), most of which, apart from the live strains, is either a carrier fiber containing no caloric value, or a trace of a natural sugar containing only a negligible value. When these teensy quantities of 1g - 3g are added to a quart of dairy, the starter's original caloric values, if ever there were any, become entirely diluted in the overall mass, and are practically non-detectable. The end-product's nutritional values of calories/fats/carbs etc., come directly from the dairy that the starter was added to, not from the starter itself. For example, if you use half-and-half, it will add more fat to your end-product than skim milk. 
  • How long does an unopened sachet of starter culture keep in the refrigerator? The Best By date is printed on the pouch and on each sachet. Please keep the starter culture refrigerated/frozen.
  • How long will the cultured dairy (the end-product) keep in the refrigerator? It will be good for several weeks. Flavor and texture may change over time.
  • How much L. Gasseri Superfood should I eat? Start with 1 teaspoon a day for the first couple of days. If all goes well, gradually increase the quantity until you reach ½ cup a day. If all is well, and depending on your individual considerations, you may increase that too.
  • Can I eat L. Gasseri Superfood if I’m lactose intolerant? Typically yes, since the prolonged fermentation converts the lactose into lactic acid, but to be sure, start small and see how you feel. If all goes well, increase the quantity. 
  • Is L. Gasseri Superfood hard to make? No, not at all. The first time is understandably a bit more demanding, because you're not yet familiar with the process. But you will soon get the hang of it, and subsequent batches (where some of your previous batch is used as a starter) will be much easier -- as easy as taking some dairy out of the fridge, whisking it with the starter and prebiotic fiber, and placing the jar in the fermenting appliance. Really easy!
  • Can I make Greek-style “yogurt”? Yes, strain the end-product through a cheesecloth to remove some of the whey.
  • Can I heat the L. Gasseri Superfood, or add it to a hot dish? This is not recommended. L. Gasseri is sensitive to high heat. High cooking temperatures would kill it.
  • Can I freeze the cultured dairy? Yes. Freezing does not kill the bacteria. You can make ice cream with it. Please note, however, that we haven't tested batches recultured from a previously-frozen batch.
  • Can I use metal utensils and lids to handle ferments? Overall yes, because the metal used in utensils and food-grade lids is most probably acid-resistant, and the utensil is not going to touch the ferment for very long. Metal lids can be used provided that they are acid-resistant and do not directly touch the fermented product for an extended period of time. Opt for the type of lids with a waxy interior, used for pickles, for example. If that interior is corroded though, better not use it. Also: the jar should not be full all the way to the top, to avoid direct contact between the ferment and the lid. There's no problem using stainless steel in the preparation stage, before fermenting.
  • Can I use a blender with the L. Gasseri? Better not. Blending is too forceful for the L. Gasseri which are living microorganisms. Blending could result in the shearing of some of the L. Gasseri bacteria, in which case you will get fewer live strains. Whisking, on the other hand, is fine. If you're making a smoothie, we recommend either to stir the L. Gasseri into the smoothie after the rest of the ingredients have been blended, or to keep the blending to a minimum and to use the lowest speed possible.
  • Can I make/consume L. Reuteri and L. Gasseri superfoods together? We have not tested this, so we cannot tell what the composition of such mixed batches might be, or how it might affect you. Nor did we test the resulting compositions of two separate jars (one with L. Reuteri, the other with L. Gasseri) fermented side by side at the same time in the same device.


My batch separated into curds and whey (solids and liquids) Separation

A separated batch is usually perfectly good and creamy and delicious. Separation is mostly a cosmetic thing. 

Separation of L. Gasseri cultured dairy is quite common, and happens spontaneously. It's the natural outcome of a long and active fermentation. It's a sign of activity and viability, not of inactivity/faultiness/failure. It’s usually not a sign that you did something wrong either. 

( Did you know, by the way, that store-bought yogurts tend to separate during production? If they look smooth and uniform, it's because a stabilizer additive is added to them in the factory. We, at Cutting Edge Cultures, on the other hand, do not put additives in our L. Gasseri starter culture.)  

If your end-product is pleasantly tart (this is the hallmark of fermentation), with no bitter aftertaste, then it is usually successfully fermented. You can eat a separated batch or add it to a smoothie. It’s rich and flavorful. (Conversely, if your jar is unpleasantly pungent, you don't want to use it.)

The jar in the picture came out delectable. The curds were used as a soft-cheese spread on a slice of bread, while a bowl of curds and whey, gently stirred together and topped with fruit, was enjoyed as a refreshing dessert.

See here for delicious recipes using separated batches, including ice cream, vinaigrette, beverages, and condiments.

A jar of separated L. Gasseri contains the same quantity of beneficial bacteria as a non-separated jar. The L. Gasseri are present in both the solids (curds) and the translucent liquid (whey), and therefore both should be consumed. Whey is often dubbed ‘liquid gold’. It's highly nutritious. 

You can use 2 tablespoons of a separated batch (1 tbsp. of whey and 1 tbsp. of curd, or 2 tbsp. of whey if the curd is too firm) to make your next batch, and this will be the ultimate test. If your new batch comes out thick and nicely tart, even if separated, then fermentation has been successful.

You can stir/whisk the solid and liquid back together just before consumption, but they will most likely separate again shortly thereafter.

L. Gasseri is not a yogurt. It's a unique cultured dairy with a unique fermentation process that yields a unique end-product which, depending on the dairy used, often looks different from other fermented dairy products, and often separates spontaneously, regardless of any measures you use in trying to prevent separation.

Given that L. Gasseri is not a yogurt, it shouldn't be compared to yogurt. Such comparison would be the equivalent of comparing apples to oranges, and wondering why the apples, despite all our efforts, don't make orange juice. That's because they're apples, not oranges. In much the same way, L. Gasseri is simply not a yogurt.

Our L. Gasseri Superfood Starter was conceived as a method of introducing high quantities of the beneficial bacteria L. Gasseri into your microbiome. This goal is achieved whether the dairy is separated or not. In terms of bacterial counts, the texture doesn't matter. The fermentation of the starter culture in dairy for 36 hours at a low temperature enables the L. Gasseri to proliferate many times over, until there are hundreds of billions of live bacteria in the jar. The resulting concentrations of L. Gasseri are much higher than can be obtained from any currently available supplement or yogurt (including homemade) that we know of. (More on bacterial counts here). It's also much more affordable than supplements, and saves you the trouble of having to crush tablets in order to create a starter.

Generally speaking, embracing this spontaneous separation is probably a better strategy than trying to prevent it at all costs. 

Tips that may help reduce separation somewhat:

    • Use ultra-pasteurized dairy, homogenized, preferably organic, without additives (half and half / whole milk / 2%). Note that using a combination of two different types of dairy (or using non-homogenized dairy), may increase chances of separation, due to differences in fat content.
    • When you make the recipe, use a whisk, rather than a spoon, to ensure even distribution of starter/fiber throughout the mixture
    • If you have the option, use large jars (1-quart or 2-quart) rather than small individual jars. (This helps with even distribution of starter/fiber throughout the mixture)
    • Do not open your device/jar(s) to check on your ferment during fermentation. You want to prevent airflow and condensation (and hence possible contaminants) from entering the mixture.
    • Heating the milk to 195°F/90°C for 10 minutes, and letting it cool to 100°F before starting the recipe, sometimes helps reduce separation somewhat. But if your ferment is nicely tart, don't worry too much about the separation.
My batch expanded outside of the jars

This can sometimes happen, especially if you didn't use ultra-pasteurized dairy. This could happen for several reasons:

  • You may have screwed the lid on the jar too tightly, and this caused pressure to build up.
  • It may be that the starter and prebiotic were not evenly distributed in the mixture. (When making the recipe, better use a whisk to mix the starter and prebiotic fiber throughout the dairy)
  • Perhaps the appliance overheated to above 100°F. Test your device with a cup of water and a thermometer before making the recipe. If it is above 100 F, lower the temperature to 98 F or even 97 F. 
  • The jar may have been too full.         

For obvious reasons, it's hard for us to assess your ferment from afar, but overall, fermented L. Gasseri should be pleasant to consume. If it's unpleasant, you may not want to use it. This will be your call. Ultimately, what you're looking for in the end-product is:

  • Flavor: nicely tart with no bitter aftertaste
  • Smell: some faint sour/tangy-dairy aroma, or none. It shouldn't smell spoiled.
  • Consistency: depending on the dairy used, fairly thick (the solid), even if separated. If a white-ish discoloration occurs at the top, scrape it off and then check the smell and flavor of the layer underneath.
What's the pink/white stuff at the top of my jar? 

This is usually a harmless yeast that forms due to air exposure or uneven distribution of the ingredients in the mixture. If this happens after several subsequent batches, and especially if it happens repeatedly and smells funky, it could also be a sign that it's time to start over with a starter from a sachet, rather than keep using the ferment itself as a starter. Scrape off the top layer and discard it. If the remaining quantity is pleasantly tart, with no bitter aftertaste, it should be fine to consume. Tip: When you make a batch of L. Gasseri Superfood, use a whisk. This will help to evenly distribute the ingredients in the mixture. Also, make sure you have a loose lid on the jars, and don't open the lids during fermentation. 

What could interfere with fermentation?
  • Fermenting temperature above 100 F (L. Gasseri are sensitive to heat)
  • Using dairy with additives
  • Uneven distribution of the ingredients in the mixture. (When making the recipe, better use a whisk to mix the starter and prebiotic fiber throughout the dairy)
  • Insufficient prebiotic fiber (the bacteria need it as food)
  • Unclean utensils (contamination)
  • Placing the jar near air flow such as a heater, air conditioning or air vent (contamination)
  • Opening the fermenting vessel/jar(s) during fermentation (contamination)
  • Not covering the jar(s) with a loosely-fitting lid/plastic wrap (contamination)

Important! Separation is not a sign of failure. See section 'My batch separated into curds and whey (solids and liquids)'

Need more info?
Go to L. Gasseri DAIRY Instructions
Go to L. Gasseri VEGAN Instructions
Go to L. Gasseri Research

Go to Cultured Dairy Recipes