Comparing Probiotics in Milk Kefir and Water Kefir

March 17, 2025

Kefir is a fermented beverage that is a probiotic powerhouse and may have positive effects on intestinal health. Did you know there are two forms of kefir: milk and water? While both provide probiotics, they differ greatly in terms of composition and the helpful bacteria and yeasts they contain.

This guide explores the distinctions between milk and water kefir to help you decide which probiotic option is best for you.

What are probiotics, and why do they matter?

Probiotics are live bacteria that, when taken in sufficient quantities, provide health advantages to the host. They primarily assist gut health by promoting healthy gut flora, which is needed for digestion, immunity, and even mental wellness.

Now that we know what probiotics are, let's look at how they appear in kefir.

What is milk kefir?

Milk kefir is made by fermenting milk (cow, goat, or sheep) with milk kefir grains. These grains are a complex symbiotic culture of bacteria and yeasts (SCOBY) embedded in a matrix of proteins, lipids, and sugars. Milk kefir boasts a creamy texture and a tangy flavour similar to yoghurt.

Does the mere mention of sugar water cause a sugar rush? Watch this video to see why sugar may not be as awful as you believe!

So, what kind of probiotics can you find in milk kefir?

Probiotic diversity in milk kefir

Milk kefir is obtained by fermenting milk with kefir grains, a symbiotic culture of bacteria & yeasts. This unique combination results in a diverse range of probiotic strains, including:

Lactobacillus: These bacteria are known for their ability to improve lactose digestion and enhance gut health.
Bifidobacterium: These beneficial bacteria play a vital role in maintaining a healthy gut microbiome & helping immune function.
Streptococcus: These bacteria contribute to the tangy flavour of milk kefir and also possess probiotic properties.
Saccharomyces: These yeasts contribute to the carbonation of milk kefir and also exhibit probiotic benefits.

Read this: Drinking Kefir: Its Health Benefits and Role in Fasting

Now, let's switch gears and explore water kefir.

What is water kefir?

Water kefir is made by fermenting sugar water with water kefir grains (also called tibicos). These grains are also a SCOBY, but they have a different composition than milk kefir grains. The resulting beverage is a light, fizzy drink with a slightly sweet and tangy flavour.

Just like milk kefir, water kefir has its own unique set of probiotics.

Probiotic profile of water kefir

Water kefir is obtained by fermenting sugar water with water kefir grains, which are composed of a different set of microorganisms. The primary probiotic strains found in water kefir include:

Lactobacillus: Similar to milk kefir, water kefir also contains various species of Lactobacillus, contributing to its probiotic benefits.
Acetobacter: These bacteria produce acetic acid, which gives water kefir its characteristic tart flavour.
Gluconobacter: These bacteria also contribute to the production of acetic acid and other beneficial compounds in water kefir.
Saccharomyces: Yeasts in water kefir contribute to carbonation and also exhibit probiotic properties.

Now that we've looked at each type individually, let's compare them directly.

Comparing probiotic content: Milk kefir vs. Water kefir

Both milk and water kefir are indeed excellent sources of probiotics, but they have distinct microbial profiles:

Diversity: Milk kefir generally exhibits a greater diversity of bacterial and yeast species. Studies have identified a wider range of strains in milk kefir, sometimes exceeding 50 different types of bacteria and yeasts.

This high diversity is one of the reasons milk kefir is often touted as a particularly potent probiotic food. Water kefir, while still diverse, typically has a smaller number of species, often ranging from 10-20.

CFU (Colony Forming Units) Count: Both milk and water kefir can achieve high CFU counts, meaning they contain a large number of live microorganisms. However, it's difficult to give an exact number, as the CFU count is highly variable. Several factors influence it:

Fermentation Time: Longer fermentation generally leads to higher CFU counts up to a certain point.
Temperature: Warmer temperatures can accelerate fermentation and potentially increase CFU counts, but excessively high temperatures can harm the microorganisms.
Specific Kefir Grains: The microbial composition of the kefir grains themselves can vary, influencing the final CFU count.
Starting Materials: The type of milk or sugar water used can also play a role.

Therefore, while both can be potent sources of probiotics, it's not accurate to say one definitively has more CFUs than the other without specific testing.

Types of Microorganisms: This is where the most significant difference lies. While there's some overlap, milk and water kefir host different dominant strains:

Milk Kefir: Dominated by lactic acid bacteria (LAB), particularly various Lactobacillus species (like Lactobacillus kefiranofaciens, which is almost unique to kefir), Lactococcus, Streptococcus, and Leuconostoc. It also contains yeasts like Saccharomyces cerevisiae, Kluyveromyces marxianus, and others.

The presence of Lactobacillus kefiranofaciens is particularly noteworthy, as it produces kefiran, a unique polysaccharide with potential health benefits.

Water Kefir: It also contains LAB, but it often contains different strains than milk kefir. Common bacteria include Lactobacillus casei and Lactobacillus brevis. The yeast population is also distinct, featuring species like Saccharomyces cerevisiae, Kazachstania exigua, and Zygotorulas.

Different Microbial Makeup = Different Benefits: The distinct microbial profiles of milk and water kefir may contribute to slightly different health effects. However, more research is needed to understand these nuances fully.

Both support gut health, but due to their unique components, such as kefiran, milk kefir is sometimes associated with additional benefits, such as improved lactose digestion and potential immune-modulating effects.

Water kefir, on the other hand, is a great option for those who avoid dairy or are seeking a lighter, more refreshing beverage.

Nutrient Content

Milk Kefir:

Protein: Contains protein from the milk source.
Calcium: Rich in calcium, especially important for bone health.
Vitamins: Provides B vitamins (B12, B2, B6) and vitamin D (if fortified).
Lactose: Contains lactose, which may be an issue for individuals with lactose intolerance.
Fat: Fat content varies depending on the type of milk used.

Water Kefir:

Low in Calories: Generally low in calories and fat.
Vitamins and Minerals: Provides trace amounts of B vitamins and minerals from the sugar source.
Lactose-Free: Naturally lactose-free, making it suitable for those with lactose intolerance.
Sugar Content: Sugar content depends on the amount of sugar used in the fermentation process.

Flavor Profile

Milk Kefir:

Tastes tangy and slightly sour, with a creamy texture.
Flavor can vary depending on the type of milk used (cow, goat, sheep, etc.).
Can be enjoyed plain or flavored with fruits, nuts, or honey.

Water Kefir:

Typically has a lighter, more effervescent flavor.
Can be quite tart, depending on the fermentation time.
Highly versatile for flavoring, well-suited for mixing with juices, fruits, or herbs.

Dosage

General Recommendation: For both milk and water kefir, a typical starting dosage is around 1-2 ounces per day.

Gradual Increase: It's generally recommended to start with a small amount and gradually increase your intake to assess your body's tolerance.

Individual Variation: The optimal dosage can vary depending on individual factors such as age, health status, and gut health.

In summary, both milk and water kefir are valuable sources of probiotics, but they offer different microbial compositions and potentially different benefits. The best choice depends on one's dietary needs, preferences, and health goals.

Potential health benefits: A comparative look

Both milk kefir & water kefir are rich in probiotics, offering numerous health benefits due to their impact on gut health and overall wellness. Here's how they compare:

1. Gut health

Both milk and water kefir contain beneficial probiotics that help balance the gut microbiome. These probiotics can support digestion, promote regular bowel movements, and alleviate digestive issues like bloating and constipation.

2. Immune support

A healthy gut is closely linked to a stronger immune system. By fostering a balanced gut microbiome, both kefir types can indirectly support immune defence, helping the body more effectively fend off infections and illnesses.

3. Milk kefir-specific benefits

Milk kefir offers unique advantages due to its dairy base:

Lactose digestion: The fermentation process reduces lactose content, making milk kefir easier to digest for some individuals with mild lactose intolerance.
Bone health: Milk kefir is a natural source of calcium, vitamin D, and vitamin K2, which are essential for maintaining strong bones and preventing osteoporosis.

4. Water kefir-specific benefits

Water kefir stands out for those seeking a dairy-free probiotic option:

Dairy-free and vegan-friendly: Since it's made with water, it suits individuals with dairy allergies, lactose intolerance, or those following a vegan diet.
Hydration support: Water kefir is a refreshing, hydrating beverage, often enhanced with fruits and herbs for added nutritional value.

Both beverages offer unique health advantages, making them versatile choices for improving gut health and overall well-being.

Must read: Storing Water Kefir: Plastic or Glass?

So, how do you choose between the two?

Choosing the right kefir for you

The best kefir for you depends on several individual factors, including your dietary needs, taste preferences, and specific health goals. Let's break down these considerations:

Dietary restrictions: This is often the primary deciding factor.

Dairy allergies or lactose intolerance: If you have a dairy allergy (an immune response to milk proteins) or lactose intolerance (difficulty digesting lactose, the sugar in milk), water kefir is a clear choice. It's made with sugar water and is naturally dairy-free.

Milk kefir, on the other hand, is made with milk and contains lactose, making it unsuitable for those with dairy restrictions.

Vegan or plant-based diets: Water kefir is also suitable for vegans and those following plant-based diets, as it does not contain animal products.

Flavour and texture preferences: The taste and texture of milk and water kefir are quite different:

Milk kefir: It has a creamy, yoghurt-like consistency and a tangy, slightly acidic flavour. Some describe it as similar to drinkable yoghurt, making it a good option for those who enjoy dairy-based fermented products.

Water kefir: It's lighter, thinner, and more effervescent than milk kefir. Its flavour is typically described as slightly sweet and tangy, with variations depending on the type of sugar and any added flavourings.

It's often compared to a naturally fizzy soda or a light cider. If you prefer a lighter, more refreshing drink, water kefir might be more appealing.

Specific health goals: While both types of kefir offer general gut health benefits due to their probiotic content, some research suggests potential differences in specific benefits:

General gut health: Both milk and water kefir can contribute to a healthy gut microbiome, which can improve digestion, nutrient absorption, and immune function.

Lactose digestion: Milk kefir may be particularly beneficial for individuals with mild lactose intolerance. The fermentation process lessens the lactose content, and the bacteria present can further aid in lactose digestion.

However, it's not recommended for those with severe lactose intolerance or dairy allergies.

Bone health: Milk kefir is a good source of calcium and vitamin K2, both of which are important for bone health.

This makes it potentially beneficial for supporting bone density and reducing the risk of osteoporosis. Water kefir does not naturally contain these nutrients in significant amounts.

Blood sugar management: Some preliminary studies suggest that both milk and water kefir may have a positive affect on blood sugar management, but more research is needed in this area.

By expanding on these points, the section provides more concrete information to help readers make an informed choice based on their circumstances. It also clarifies the differences between dairy allergies and lactose intolerance, which is a common point of confusion.

Regardless of which you choose, there are some important considerations.

Important considerations for all kefir consumption

Start slowly: If you're new to kefir, start with small amounts and gradually increase your intake to avoid potential digestive upset.
Listen to your body: Pay attention to how your body responds to kefir and adjust your consumption accordingly.
Consult with a healthcare professional: If you have any underlying health conditions or are taking medications, consult with a healthcare professional before consuming kefir.

In conclusion, both types of kefir are great for your health.

Both milk and water kefir are excellent sources of probiotics and offer potential health benefits. While they differ in their microbial composition and flavour profiles, both can be valuable additions to a healthy diet. Choosing between them depends on your individual needs, preferences, and dietary restrictions.

For a trusted source of probiotics, consider The Good Bug's range of kefir products to support your gut health journey.