How do you start kefir from scratch?

November 29, 2025 •

4 min read

The market for functional and fermented foods is a multi-billion dollar industry, with many consumers turning to homemade options for gut health [2, 3]. Starting your own kefir is a simple way to create a probiotic-rich beverage. This guide explains how you start kefir from scratch using either milk or water kefir grains, providing a sustainable source of beneficial bacteria.

Quick Summary

A comprehensive guide on creating homemade kefir using live grains. Includes simple instructions for both milk and water varieties, fermentation tips, and what to expect during the process.

Key Points

Acquire Live Grains: True kefir cannot be started without live milk or water kefir grains; they must be purchased or sourced.
Avoid Metal Utensils: Always use non-metal strainers and spoons when working with kefir grains to prevent damage from reactive metals [5].
Use Quality Ingredients: High-quality milk (for milk kefir) or organic cane sugar and filtered water (for water kefir) are crucial for feeding the grains [5, 7].
Maintain Temperature: Consistent room temperature is important for successful fermentation, generally between 68-85°F (20-30°C) [5].
Observe and Taste: Pay attention to the signs of healthy fermentation, such as thickening and separation in milk kefir, and adjust your process as needed.
Be Patient with Activation: The first few batches of kefir, especially with dormant grains, may take longer or taste different as the grains wake up and adjust.

Understanding the Basics: What You Need

Starting kefir from scratch fundamentally requires live kefir grains, a symbiotic colony of bacteria and yeast (SCOBY). Unlike sourdough starter, you cannot cultivate kefir grains from scratch; they must be acquired from a trusted source or a fellow fermenter [6].

What are Kefir Grains?

Kefir grains are not cereal grains but small, gelatinous, cauliflower-like masses containing the beneficial microbes necessary for fermentation. These grains consume the lactose (in milk) or sugar (in water) and produce a tangy, effervescent, and probiotic-rich beverage. The grains multiply over time, providing a self-sustaining source of kefir.

Essential Equipment

Kefir Grains: Live milk or water kefir grains.
Glass Jar: A 1-quart or 1-liter jar is a good starting size.
Strainer: A plastic fine-mesh strainer or nylon mesh is essential. Avoid metal strainers, as metal can harm the grains over time [5].
Spatula/Spoon: A non-metal utensil for stirring.
Breathing Cover: A coffee filter, cheesecloth, or loose jar lid to allow gases to escape while keeping contaminants out.
Storage Container: A jar with a tight-fitting lid for storing finished kefir in the refrigerator.

Starting Milk Kefir from Scratch

Making milk kefir is a straightforward process that yields a creamy, tangy drink. The first few batches, known as 'activation' or 'transition' batches, may not taste perfect, but the grains will settle into a rhythm.

Prepare the Grains: If your grains arrived dormant or dehydrated, you will need to activate them according to the supplier's instructions. If they are already active, you can begin immediately [6].
Combine Ingredients: Place 1-2 tablespoons of milk kefir grains into a clean glass jar. Add 1 cup of fresh, high-quality milk. Whole, pasteurized milk is a great starting point for robust grains [5].
Cover and Ferment: Place a breathable cover over the jar and secure it with a rubber band. Place the jar in a warm spot, out of direct sunlight. The ideal fermentation temperature is 68–85°F (20–30°C) [5].
Monitor Fermentation: Fermentation typically takes 12-48 hours. You will know it's ready when the milk has thickened and you see pockets of whey (a yellowish liquid) separating from the curds [5].
Strain the Grains: Once ready, gently stir the contents with a plastic spoon and strain the kefir into a new jar, catching the grains with the plastic strainer [5].
Start a New Batch: Immediately place the strained grains back into the original jar and add fresh milk to begin the next batch.

Starting Water Kefir from Scratch

Water kefir is a lighter, slightly carbonated alternative to milk kefir. The process is similar but requires a specific sugar-water solution.

Activate Grains: Follow your supplier's instructions for activating dehydrated or dormant water kefir grains. Active grains can be used immediately [7].
Prepare the Sugar Water: In a glass jar, dissolve ¼ cup of organic cane sugar into 1 quart (4 cups) of warm, filtered water. Stir until fully dissolved. Allow the water to cool to room temperature before proceeding [7].
Add Grains and Optional Ingredients: Add 1-2 tablespoons of water kefir grains to the sugar water. For added minerals and flavor, you can include a slice of lemon and a few raisins or dried figs [7].
Cover and Ferment: Cover the jar with a breathable cloth and secure it. Place it in a warm, dark location for 24-48 hours [7].
Strain and Store: Strain the water kefir into a clean jar, reserving the grains for the next batch. The finished water kefir can be drunk immediately or undergo a second fermentation.
Start the Next Batch: Refresh the sugar water and repeat the process with the strained grains [7].

Comparison: Milk Kefir vs. Water Kefir


Feature	Milk Kefir	Water Kefir
Grains	Milky, soft, cauliflower-like masses	Small, translucent, crystal-like grains
Fermentation Liquid	Cow, goat, or other milk	Filtered water with sugar, sometimes fruit
Flavor Profile	Tangy, creamy, slightly sour, can be fizzy	Mildly sweet, slightly tart, effervescent
Second Fermentation	Often done to add flavor (e.g., fruit, vanilla)	Common for carbonation and flavor (e.g., juice)
Nutritional Profile	Contains lactose (less than milk), high in protein and calcium	Lower in calories, no dairy, contains different probiotic strains
Dietary Suitability	Not suitable for those with dairy allergies or who are vegan	Dairy-free, suitable for vegans

Common Problems and Troubleshooting

Grains Not Activating: Some grains may need a few batches to wake up. Give them fresh milk or sugar water and be patient. Ensure the temperature is correct [5, 7].
Off-Flavor/Smell: If the kefir smells yeasty or cheesy, it might be fermenting for too long. If it smells bad or has mold, discard the batch and rinse the grains [5].
Kefir Is Not Thickening (Milk Kefir): This can be due to temperature, grain-to-milk ratio, or grain health. Try a warmer spot or a bit less milk. Sometimes, the grains just need a few batches to get going [5].
No Fizz (Water Kefir): Lack of effervescence can be a sign of tired grains or not enough sugar. Ensuring the water is filtered and the sugar is good quality helps [7]. Adding a slice of fruit during the primary fermentation can also help provide nutrients.
Grains Reproducing Slowly: This can be caused by low-quality ingredients, inadequate temperature, or aging grains. Ensure you are using high-quality milk or a good source of minerals for water kefir.

Conclusion: Enjoying Your Homemade Kefir

Learning how to start kefir from scratch is a rewarding process that provides you with a consistent supply of delicious, probiotic-rich beverages. Whether you choose the creamy tang of milk kefir or the light effervescence of water kefir, the key is to be patient and attentive to your grains. With proper care, your grains will thrive and multiply, allowing you to share the joy of homemade kefir with others. Enjoy experimenting with second fermentations to add your favorite flavors and create unique custom drinks.

Visit a resource like the National Center for Complementary and Integrative Health for more information on probiotics and health.

Frequently Asked Questions

No, you cannot make true, traditional kefir without live kefir grains. Kefir grains are the specific symbiotic colony of bacteria and yeast that ferment the milk or sugar water to create kefir. While there are powdered starter cultures, they produce a single batch and cannot be re-cultured indefinitely like grains.

You can purchase live kefir grains from a number of reputable online suppliers or health food stores. Some home fermenters may also share their extra grains with others, often found through online fermentation communities or local groups [6].

Most milk kefir grains thrive on whole, pasteurized cow's milk. While you can use other types like goat's milk or even plant-based milks, the latter may require specific instructions or a 'transition' period for the grains [5].

Active kefir grains will produce kefir consistently. For milk kefir, this means the milk thickens and separates within 12-48 hours. For water kefir, you will see bubbles forming and the water will become cloudy. You will also notice the grains multiplying over time [5, 7].

If your milk kefir isn't thickening, it could be due to a cool room temperature, a poor grain-to-milk ratio, or unhealthy grains. Try moving the jar to a warmer spot or adding more grains. The grains may also just need a few batches to become fully active [5].

For a short break (up to a few weeks), you can place your grains in fresh milk or sugar water and store them in the refrigerator [5]. For longer breaks, water kefir grains can be dried, while milk kefir grains can be frozen or dried.

While organic cane sugar is the most recommended for water kefir grains, you can experiment with others like coconut sugar or molasses for different flavors. However, some sweeteners may not provide the necessary nutrients for the grains to thrive [7].