Making Water Kefir in an Open Jar: A Step-by-Step Guide

January 15, 2025

If you're exploring fermented beverages, you’ve likely come across water kefir—a refreshing, probiotic-rich drink made by fermenting sugar water with kefir grains. But what if you don’t have a fancy airtight container? Can you make water kefir in an open jar? The short answer is yes, but with some important considerations!

This guide will take you through the step-by-step process of safely and effectively making water kefir in an open jar, ensuring delicious results every time.

What is water kefir?

Water kefir is a naturally fermented beverage made by combining water, sugar, and water kefir grains—a symbiotic culture of bacteria and yeast (SCOBY). The fermentation process turns sugar into beneficial probiotics and organic acids, creating a refreshing, fizzy, and slightly sweet drink.

Unlike traditional milk kefir, which is made from dairy, water kefir is dairy-free, making it an excellent option for those following a vegan or dairy-free diet.

Why ferment in an open jar?

Using an open jar for fermentation allows the grains to breathe and thrive. As long as proper hygiene and contamination prevention are maintained, it’s an accessible option for beginners who don’t have specialized equipment.

Convenience: Open fermentation eliminates the need for burping bottles, which can be messy and time-consuming.
Reduced Pressure Buildup: Fermenting in an open jar minimizes the risk of bottle explosions due to excess carbonation.
Easier Monitoring: You can easily observe the fermentation process and make adjustments as needed.

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Now that we understand water kefir let’s discuss the steps for making it in an open jar.

How to make water kefir in an open jar

Making water kefir in an open jar is a simple and cost-effective method.

Supplies you'll need

To make water kefir in an open jar, you’ll need a few essential supplies:

Water kefir grains: These live cultures of bacteria and yeast (SCOBY) ferment sugar water into a probiotic-rich drink. Ensure you obtain active, high-quality grains from a trusted source to guarantee proper fermentation.
Sugar: Natural, unprocessed sugars like cane sugar, coconut sugar, or jaggery work best. Avoid using honey, as its antibacterial properties can disrupt the fermentation process.
Mineral water: Use filtered or mineral-rich water, as chlorinated tap water can harm the delicate kefir grains.
Open jar: A clean glass jar is ideal for fermentation. Choose a jar large enough to accommodate the grains and the fermenting liquid.
Covering material: Use a breathable material like muslin cloth, cheesecloth, or a coffee filter. Secure it with a rubber band to keep contaminants out while allowing airflow.
Non-metallic utensils: Always use plastic or wooden spoons to stir or handle the grains, as metal can damage their structure and affect fermentation.

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Here’s a step-by-step guide to help you get started

A step-by-step guide to making water kefir in an open jar

Making water kefir in an open jar is a straightforward process. Below, we’ll break down each step in detail to ensure your kefir turns out perfectly every time.

Step 1: Prepare the sugar water

Sugar water forms the nutrient-rich base needed for fermenting water kefir. Here’s how to prepare it correctly:

Measure the sugar-to-water ratio:

Use 1 tablespoon of sugar for every 1 cup of water. If your jar holds a quart (4 cups), you’ll need 4 tablespoons of sugar. Adjust these quantities based on the size of your jar.

Dissolve the sugar:

Heat a portion of the water slightly (not boiling) and add the sugar. Stir until it dissolves completely. Heating helps the sugar integrate into the water, but ensure the water doesn’t boil as it might degrade some minerals.

Cool the sugar water:

Once the sugar is dissolved, let the mixture cool to room temperature. This is crucial because hot water can kill the beneficial bacteria and yeast in the kefir grains.

Combine with the rest of the water:

If you initially heated only part of the water, mix it with the remaining cool water to reach the desired volume for your jar.

Use filtered or mineral-rich water. Avoid chlorinated tap water, as chlorine can harm the kefir grains. If tap water is your only option, leave it uncovered for 24 hours to allow the chlorine to evaporate.

Must read: Kefir: Discovering the Benefits of Probiotic Milk

Step 2: Add kefir grains

Once your sugar water is at room temperature, it’s time to introduce the kefir grains.

Measure the grains:

Use 1-2 tablespoons of kefir grains for every quart (1 liter) of sugar water.

Add grains to the jar:

Gently place the grains into the sugar water.

Distribute evenly:

Use a non-metallic spoon (plastic or wooden) to stir the mixture gently. Metal can react with the grains and harm their activity. Stirring also ensures the grains are evenly distributed in the water, which promotes balanced fermentation.

Step 3: Cover the jar

Since you’re fermenting in an open jar, protecting the mixture while allowing airflow is critical.

Choose a breathable cover:

Use a muslin cloth, cheesecloth, coffee filter, or any clean, breathable material. Avoid tight lids, as they can trap fermentation gases, leading to pressure buildup.

Secure the cover:

Place the cloth or filter over the jar opening and secure it with a rubber band. This setup prevents dust, insects, or contaminants from entering while allowing the necessary exchange of gases.

Step 4: Allow fermentation

Fermentation is where the magic happens. At this stage, the kefir grains transform sugar water into a tangy, probiotic-rich drink.

Choose a fermentation spot:

Place the jar in a warm, dark spot with a stable temperature of 68-78°F (20-26°C). Ideal locations include kitchen counters away from direct sunlight or a pantry shelf.

Ferment for 24-48 hours:

Allow the mixture to ferment for 24-48 hours, depending on your flavor preference. A shorter fermentation yields a sweeter drink, while a longer one produces a tangier, less sweet kefir.

Monitor activity:

Look for bubbles rising to the surface, which indicate active fermentation. After 24 hours, you can taste the kefir to determine whether it’s ready.

Adjust for preferences:

If you prefer a slightly less tangy flavor, strain the kefir at 24 hours. For a stronger flavor, let it ferment for closer to 48 hours. Avoid fermenting beyond 48 hours as it may turn overly sour and reduce the grains' activity.

Step 5: Strain and store

Once fermentation is complete, it’s time to separate the grains and store your water kefir.

Strain the mixture:

Use a fine plastic or nylon strainer to separate the kefir grains from the liquid. Avoid metal strainers, as they can react with the grains and harm their effectiveness.

Transfer the liquid:

Pour the strained water kefir into a clean glass bottle or jar. If you prefer a fizzy drink, seal the bottle tightly and let it sit at room temperature for an additional 12-24 hours to build carbonation. This process, called second fermentation, enhances the flavor and texture.

Refrigerate the kefir:

Once the second fermentation is complete (if desired), store the kefir in the refrigerator. Chilling stops the fermentation process and preserves the drink’s freshness.

Rinse and reuse the grains:

Rinse the grains gently with clean water to remove any residue. They’re now ready for your next batch.

If you won't be making a new batch immediately, keep the grains in fresh sugar water. Store them in the refrigerator to keep them active.

Also read: Restoring Gut Health and Flora After Antibiotics.

Now that you know how to make water kefir in an open jar, let’s discuss some tips and troubleshooting advice to help you succeed.

Tips for making water kefir in an open jar

Following these tips, you can ensure a smooth and successful fermentation process, resulting in a delicious, probiotic-rich drink.

1. Maintain cleanliness

Cleanliness is crucial for successful fermentation. Before starting, ensure all your equipment, including jars, utensils, and strainers, is thoroughly cleaned and sanitized. This step minimizes the risk of contamination from unwanted bacteria or mold.

2. Avoid over-fermentation

Over-fermenting can result in an overly sour or acidic taste, which might not be palatable. Check your kefir after 24 hours and taste it.

Suppose it meets your flavor preference, strain and bottle it immediately. If you like it tangier, let it ferment for another 12-24 hours, but monitor it closely.

3. Use non-chlorinated water

The beneficial bacteria in water kefir grains are sensitive to chlorine and other chemicals found in tap water. Always use filtered, spring, or dechlorinated water to create an environment where the grains can thrive.

If tap water is your only option, let it sit uncovered for 24 hours to allow the chlorine to evaporate.

4. Pay attention to temperature

Fermentation works best at a consistent temperature between 68-78°F (20-26°C). Keep the jar in a warm, dark spot, away from direct sunlight or heat sources. Extreme temperatures—either too hot or too cold—can inhibit the fermentation process or damage the grains.

5. Monitor and care for your kefir grains

Healthy kefir grains are essential for successful fermentation. If you notice they aren’t fermenting properly, they might need a "rest" period in plain sugar water or additional sugar to regain their vitality.

Regular feeding and proper care will keep the grains active and productive for future batches.

Let’s wrap up with some common questions about making water kefir in an open jar.

Common questions about making water kefir in an open jar

1. Is it safe to ferment in an open jar?

Yes, it’s safe as long as you follow proper hygiene practices and cover the jar securely to prevent contaminants. The breathable cover allows fermentation gases to escape while keeping harmful substances out.

2. How do I know if fermentation is working?

Bubbles in the liquid and a tangy aroma are signs of active fermentation. When ready, the kefir should taste slightly sweet and tangy.

3. What if mold forms on the surface?

Mold is rare if you maintain hygiene, but if it appears, discard the batch and start over. Clean all equipment thoroughly before the next use.

4. Can I reuse the grains?

Absolutely! Rinse the grains gently with clean water and use them for your next batch. With proper care, kefir grains can last indefinitely.

The Challenges of Open Fermentation

Evaporation: Open jars allow moisture to escape, which can affect the fermentation process and the final flavor.
Contamination: Exposure to air increases the risk of contamination from unwanted microorganisms such as mold.
Slower Fermentation: Open fermentation may result in slower fermentation times compared to closed containers.

While open fermentation presents some challenges, it can be a viable method for making water kefir. By following these tips and closely monitoring the process, you can successfully create a delicious and refreshing probiotic beverage at home.

Making water kefir in an open jar is a simple, rewarding process that allows you to enjoy a healthy, probiotic-rich drink without investing in specialized equipment.

By following this step-by-step guide, you can ferment water kefir safely and effectively. Remember to monitor the process, maintain hygiene, and experiment with fermentation times to achieve your desired flavor.

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Ready to start your water kefir journey? Explore quality kefir grains and tips from trusted sources like The Good Bug. Cheers to good health and delicious drinks!