Why Is My Kombucha Not Fizzing And How To Carbonate It Properly At Home

Many home brewers fall in love with kombucha for its tangy flavor, probiotic benefits, and satisfying effervescence. But there’s nothing more disappointing than opening a bottle expecting a crisp, fizzy pop—only to find flat, lifeless tea. If your kombucha isn’t carbonating as expected, you're not alone. Carbonation issues are among the most common challenges in home fermentation. The good news? With a few adjustments to your process, you can consistently achieve that sparkling finish you’re after.

Carbonation in kombucha comes from trapped CO₂ produced during fermentation. Unlike commercial sodas that inject gas, natural fizz develops through biology—specifically, yeast consuming sugar and releasing carbon dioxide. When this occurs in a sealed environment, the gas dissolves into the liquid, creating bubbles. But several factors can interrupt this process, leading to lackluster results. Understanding these variables is key to mastering second fermentation and achieving reliable fizz.

Understanding Why Kombucha Fails to Fizz

The absence of carbonation typically stems from one or more preventable causes. Identifying the root issue allows you to troubleshoot effectively rather than repeating the same mistakes batch after batch.

Insufficient Sugar for Secondary Fermentation

During the first fermentation (primary), much of the sugar is consumed by the SCOBY (Symbiotic Culture Of Bacteria and Yeast). For the second fermentation—where carbonation happens—you must reintroduce sugar. Without enough fermentable sugar, the remaining yeast have nothing to eat, so no CO₂ is produced.

Tip: Always add 1–2 teaspoons of sugar per 16 oz (500ml) bottle before sealing for second fermentation.

Poor Sealing of Bottles

Even if CO₂ is being produced, it will escape if bottles aren’t airtight. Standard mason jars with ring lids won’t hold pressure. You need bottles specifically designed for carbonation, such as glass swing-top (Grolsch-style) bottles or thick-walled plastic soda bottles.

Incorrect Temperature

Yeast activity slows dramatically below 68°F (20°C). If your kitchen is too cold, fermentation stalls. Conversely, temperatures above 85°F (29°C) may kill beneficial cultures or encourage off-flavors. The ideal range for secondary fermentation is 72–78°F (22–26°C).

Over-Fermenting the First Brew

If the primary fermentation runs too long, most sugars are already consumed, leaving little fuel for carbonation later. A kombucha that tastes overly vinegary likely has minimal residual sugar, reducing fizz potential.

Using Non-Fermentable Sweeteners

Honey, stevia, monk fruit, and artificial sweeteners do not feed the yeast needed for CO₂ production. Even some fruit juices contain preservatives like potassium sorbate, which inhibit fermentation.

“Consistent fizz starts with understanding microbial timing and proper bottling technique.” — Dr. Lila Nguyen, Fermentation Scientist at Oregon State University

How to Properly Carbonate Kombucha at Home: A Step-by-Step Guide

Creating naturally carbonated kombucha requires precision and patience. Follow this timeline-based method to maximize bubble formation safely and reliably.

1. Complete Primary Fermentation (7–14 Days): Brew your base kombucha using black or green tea and cane sugar. Allow it to ferment with a healthy SCOBY until it reaches balanced tartness—not too sweet, not too sour. Taste daily after day 7.
2. Prepare Flavor Additives (Optional): Use fresh fruit chunks, juice (without preservatives), herbs, or ginger. These provide both flavor and additional sugars for carbonation.
3. Bottle with Fresh Sugar: Transfer kombucha to clean, sterilized bottles. Add 1–2 tsp of sugar or 1/4 cup fruit per 16 oz bottle. This feeds the yeast during second fermentation.
4. Seal Tightly: Use air-tight bottles. Check seals on swing-top closures; ensure plastic soda bottles are free of cracks.
5. Ferment at Room Temperature (2–7 Days): Store bottles at 72–78°F away from direct sunlight. Burp bottles daily after day 3 to release excess pressure and avoid explosions.
6. Refrigerate to Stop Fermentation: Once desired fizz level is reached, move bottles to the fridge. Cold halts yeast activity and preserves carbonation.

Tip: Test carbonation by gently squeezing plastic bottles—if they feel firm, CO₂ has built up. Glass bottles should be opened carefully over a sink.

Best Practices for Reliable Carbonation: Do’s and Don’ts

Do’s	Don’ts
Add fermentable sugar (cane sugar, fruit, honey*) before bottling	Use preservative-laden store-bought juices
Use high-quality, pressure-rated bottles	Store bottles in warm areas (>85°F) for extended periods
Keep bottles at consistent room temperature	Forget to burp bottles during active fermentation
Refrigerate promptly once fizzed	Use metal lids directly on kombucha (can corrode)
Label bottles with brew date	Open bottles without protection—use a towel and point away

*Note: While honey is fermentable, raw honey contains microbes that may interfere with SCOBY health. Best used only in second fermentation.

Real Example: From Flat to Fizzy – One Brewer’s Journey

Sophie, a home fermenter in Portland, struggled for months with flat kombucha. Her first batches tasted great but lacked any noticeable bubbles. She used mason jars with standard lids, added flavored syrups she bought at the grocery store, and kept her bottles in a cool basement corner.

After researching, she made three key changes: switched to swing-top glass bottles, started adding fresh ginger and a teaspoon of sugar per bottle, and moved her brew station to a warmer cupboard near the stove. Within a week, her next batch developed a satisfying hiss upon opening. “I finally got that restaurant-style sparkle,” she said. “It was all about giving the yeast what they needed—and keeping the gas in.”

Troubleshooting Common Carbonation Problems

Even when following best practices, issues can arise. Here’s how to diagnose and fix them.

• No fizz after 7 days: Likely due to low sugar, poor seal, or cold temps. Try adding a small amount of sugar solution to each bottle, resealing, and placing in a warmer spot for 2–3 more days.
• Weak fizz that disappears quickly: Indicates partial sealing or premature refrigeration. Ensure caps are tight and allow longer conditioning at room temp.
• Too much pressure or gushing: Over-carbonation from excessive sugar or delayed refrigeration. Reduce sugar next time and refrigerate earlier. Always burp bottles daily after day 3.
• Sediment buildup: Normal. It's yeast and fiber. Shake gently before pouring or strain during bottling if preferred.

Tip: For stronger fizz, try “ginger bug” addition—a wild-fermented ginger starter rich in active yeast—to boost carbonation power.

Checklist: Ensuring Perfect Kombucha Carbonation

Before sealing your bottles, run through this essential checklist:

• ✅ Used fresh, fermentable sugar source (e.g., cane sugar, fruit, juice without preservatives)
• ✅ Added 1–2 tsp sugar or equivalent per 16 oz bottle
• ✅ Employed airtight, pressure-safe bottles (swing-top or PET plastic)
• ✅ Stored bottles at 72–78°F (22–26°C), out of direct sunlight
• ✅ Burped bottles daily starting on day 3 of second fermentation
• ✅ Refrigerated bottles once desired fizz level achieved
• ✅ Waited at least 12 hours in fridge before opening (allows CO₂ to stabilize)

Frequently Asked Questions

Can I carbonate kombucha without adding more sugar?

No—natural carbonation requires fermentable sugar. Without it, yeast cannot produce CO₂. However, the amount needed is small (1–2 tsp per bottle), and most is consumed during fermentation, so the final sugar content remains low.

Why did my bottle explode?

This usually happens when too much sugar is added, temperatures are too high, or bottles aren’t burped. Over-pressurization can also occur if kombucha is left at room temperature for more than 7–10 days. Always use strong bottles and monitor pressure buildup.

Is it safe to drink flat kombucha?

Yes. Flat kombucha is still safe and beneficial if properly fermented and stored. Lack of fizz doesn’t indicate spoilage. However, if it smells rotten, moldy, or sulfur-like, discard it.

Final Tips for Consistent, Crisp Fizz

Achieving consistent carbonation is less about luck and more about control. Monitor your environment, measure your additives, and use reliable equipment. Keep notes on each batch—sugar type, temperature, duration, and results—to refine your process over time.

Ginger, berries, citrus zest, and even pineapple chunks not only enhance flavor but also contribute fermentable sugars that support robust fizz. Experiment thoughtfully, but always prioritize safety: never use cracked or weak bottles, and keep children and pets away during active fermentation.

Remember, kombucha brewing is both science and art. Each batch teaches you something new about microbial behavior and environmental influence. With attention to detail, even beginners can produce sparkling, professionally fizzy kombucha at home.

💬 Ready to perfect your brew? Start your next batch with precise sugar additions and proper bottles—then share your fizz success story in the comments!