How to Make Water Kefir
How to Make Water Kefir at Home: Step by Step Guide
The Short Answer
To make water kefir, dissolve sugar in filtered water, add your live water kefir grains and leave to ferment at room temperature for 24 to 48 hours. Strain out the grains, start a new batch immediately, then bottle the liquid for a second fermentation to build natural carbonation. The whole process takes about 5 minutes of hands on time per batch. New to water kefir? Read our guide on what water kefir is and how it works first.
In This Water Kefir Guide
What You Need to Make Water Kefir
Equipment and Ingredients
- Live water kefir grains, 25g for a standard batch or 50g for a large batch
- Glass jar, 500ml minimum with a wide mouth
- Filtered or still mineral water, tap water contains chlorine and fluoride that can weaken the grains over time
- Organic cane sugar, the cleanest food source for the grains
- Plastic or nylon strainer, never use metal as it can damage the grains
- Breathable cover, muslin cloth or a coffee filter secured with a rubber band
- Swing top glass bottles, for second fermentation
NutriBrew Tip: Always use plastic or wooden utensils when handling water kefir grains. Metal can affect the microbial balance of the culture over time, particularly during repeated contact. A plastic sieve and a wooden or silicone spoon are all you need.
Which Sugar Works Best for Water Kefir?
The sugar you use directly affects how well your grains ferment, how consistently they grow and what your finished water kefir tastes like. Not all sugars are equal and some should be avoided entirely.✓ Organic Cane Sugar
Best choice. Clean, reliable and no residual chemicals. Most consistent results batch after batch.
✓ Dark Brown Sugar
Good for occasional use. High mineral content, useful for reviving sluggish grains. Can add a molasses flavour.
⚠ Coconut Sugar
Use sparingly. Very mineral rich. Mix at no more than 25% with cane sugar to avoid grains going soft.
✗ Honey or Sweeteners
Avoid entirely. Honey has antimicrobial properties that damage the culture. Sweeteners contain nothing the grains can ferment.
Sugar and Water Ratios for Water Kefir
Getting the ratio of sugar to water right gives your grains a consistent food supply and produces a well balanced finished drink. Too little sugar and the grains starve and shrink. Too much and the brew becomes overly acidic before the fermentation cycle is complete.Standard Batch
Grains: 25g
Water: 500ml filtered
Sugar: 30 to 40g
Large Batch
Grains: 50g
Water: 1 litre filtered
Sugar: 60 to 80g
🌿 Water kefir grains need minerals to thrive in filtered water. Add one organic raisin or a small pinch of sea salt to each batch. This replaces the trace minerals that are removed during filtration and keeps your grains healthy and growing consistently.
How to Make Water Kefir: Step by Step First Fermentation
Step by Step: First Fermentation
Step 1: Dissolve your sugar
Dissolve the sugar in a small amount of warm water, then top up with cold filtered water until you reach your target volume and the water is at room temperature, around 20 to 22°C. Never add grains to warm or hot water as heat will damage the culture.
Step 2: Add minerals
Add one organic raisin or a small pinch of sea salt to the sugar water. This provides the trace minerals the grains need to stay healthy in filtered water. Skip this step and your grains may gradually shrink and lose vitality over time.
Step 3: Add your water kefir grains
Add your live grains to the sugar water. Give the jar a gentle swirl to distribute them evenly through the liquid.
Step 4: Cover and ferment
Cover the jar with a muslin cloth or coffee filter secured with a rubber band. Place in a spot away from direct sunlight at room temperature. Ferment for 24 to 48 hours. In an Irish kitchen during winter, 48 hours is usually needed. In summer, check at 24 hours as warmer temperatures speed up the process.
Step 5: Strain and start again
Using your plastic strainer, separate the grains from the finished liquid. Put the grains straight into a new batch of sugar water to keep them active. Do not leave them sitting dry or in plain water for extended periods.
NutriBrew Tip: Taste your water kefir at 24 hours. If it is still quite sweet, leave for another 12 to 24 hours. If it tastes lightly tangy with just a trace of sweetness, it is ready. The exact timing depends on your kitchen temperature, grain health and personal taste preference.
How to Carbonate Water Kefir: The Second Fermentation
First fermentation produces the probiotic drink. Second fermentation is what gives it the fizz. This is the stage where you bottle the liquid, add fruit or flavouring, and leave it sealed for 24 to 48 hours to build natural carbonation. The result is a naturally sparkling drink you can customise completely.Step by Step: Second Fermentation
Step 1: Bottle the liquid
Pour your strained first ferment water kefir into swing top glass bottles. These are the only safe option for second fermentation as they are designed to handle the pressure that builds during carbonation.
Step 2: Add fruit or flavouring
Add a small amount of fruit juice, fresh fruit or ginger to each bottle before sealing. Around 50 to 100ml of juice per 500ml bottle works well. The natural sugars feed the remaining yeast and produce the carbonation. Browse our water kefir recipes for flavour combination ideas.
Step 3: Leave headspace
Fill each bottle leaving 2 to 3cm of air at the top. This gap is essential for carbonation to build safely without the pressure having nowhere to go.
Step 4: Ferment at room temperature
Leave the sealed bottles at room temperature for 24 to 48 hours. Burp each bottle once daily by opening briefly over a sink to check and release pressure. Once you hear a healthy hiss, move all bottles to the fridge.
Step 5: Refrigerate and enjoy
Cold temperatures stop fermentation and lock the carbonation in. Always open bottles slowly over a sink. For a full guide to getting the fizz right every time, visit our water kefir second fermentation guide.
Water Kefir Grain Care: Keeping Your Grains Healthy Long Term
Healthy grains grow a little with each batch and produce a consistent, well flavoured ferment. Here is what to watch for and how to keep your grains in good condition over time.Signs of Healthy Water Kefir Grains
- Translucent or slightly white in colour, similar to small crystals or jelly pieces
- Firm but slightly soft to the touch
- Growing slowly but consistently from batch to batch
- Producing a lightly tangy, mildly sweet finished drink within 24 to 48 hours
- Bubbles visible in the liquid during fermentation
Taking a Break from Brewing
Short break, up to 2 weeks: Place grains in a jar of fresh sugar water, seal tightly and store in the fridge. The cold slows fermentation right down. Feed with fresh sugar water once a week.
Longer break: Dry the grains by spreading them on baking paper and leaving at room temperature until fully dried. Store in an airtight bag in the freezer. To revive, rehydrate in sugar water at room temperature and feed daily for 3 to 5 days until active again.
Common Water Kefir Problems and How to Fix Them
Grains Not Growing
Cause: Mineral deficiency or chlorinated water
Fix: Add a raisin or pinch of sea salt, switch to filtered water
Grains Turning Mushy
Cause: Too many minerals, often from coconut sugar
Fix: Use plain organic cane sugar for 3 to 4 batches
No Fizz After Fermenting
Cause: First fermentation does not produce strong carbonation on its own
Fix: Bottle with fruit juice or sugar and follow our second fermentation guide to build the fizz
Tastes Too Sweet
Cause: Under fermented
Fix: Leave for another 12 to 24 hours before straining
Tastes Too Sour
Cause: Over fermented or kitchen too warm
Fix: Reduce fermentation time by 12 hours next batch
Grains Shrinking
Cause: Not enough sugar or batches left too long
Fix: Start a fresh batch immediately with correct ratio
Frequently Asked Questions About Making Water Kefir
How long does water kefir take to ferment?
First fermentation takes 24 to 48 hours at room temperature. In a warm Irish kitchen above 22°C, check at 24 hours. In a cooler kitchen below 20°C, 48 hours is usually needed. Second fermentation for carbonation takes a further 24 to 48 hours in sealed bottles at room temperature. For a full guide to getting the fizz right visit our water kefir second fermentation guide.Can I use tap water to make water kefir?
Tap water can work but filtered or still mineral water gives significantly better results. Irish tap water contains chlorine and fluoride which can weaken the grains over time, particularly if used for every batch. If filtered water is not available, boil the tap water and allow it to cool completely before use, or leave it in an open container overnight to allow the chlorine to dissipate.Why are my water kefir grains not growing?
Slow or no grain growth is almost always a mineral deficiency. Water kefir grains need trace minerals to produce the cellulose matrix that makes them grow. Add one organic raisin or a small pinch of sea salt to each batch to provide these minerals. Also check that you are using filtered water and organic cane sugar, and that your kitchen temperature is above 18°C.How do I know when my water kefir is ready to drink?
Taste it from day one using a clean spoon. Finished water kefir should be lightly tangy with just a trace of residual sweetness. If it is still quite sweet, leave for another 12 hours and taste again. If it is very sour or tastes like vinegar, it has fermented for too long. Use it in smoothies or as a starter for your next batch and reduce the fermentation time next time.Can I make water kefir without a second fermentation?
Yes. First ferment water kefir is perfectly good to drink straight after straining. It will be lightly flavoured, mildly tangy and only very slightly fizzy (if at all). Second fermentation adds the stronger carbonation and allows you to add fruit flavours, but it is optional. Many people drink their water kefir straight from the first ferment and find it refreshing and easy to enjoy.How much water kefir should I drink each day?
If you are new to water kefir, start with 100 to 150ml per day and increase gradually over one to two weeks as your gut adjusts to the increase in probiotic activity. Most regular drinkers settle at around 200 to 250ml per day. Find out more about what water kefir can do for you in our kefir benefits guide.Everything You Need for Water Kefir Success
From your first batch to advanced second fermentation, our guides cover every step.