Big Mouth Bubbles Airlock Fermentation Lid Review for Kombucha Brewers

Review at a Glance

Reviewed by the BrewCrock Editorial Team

Last Updated: June 2026 | Written by BrewCrock Editorial Team

The best big mouth bubbles airlock lid review for your situation depends on how you plan to use it and where.

This big mouth bubbles airlock lid review is the result of six back-to-back kombucha batches between March and June 2026, plus side-by-side runs against three competing fermentation lids. We brewed in a 72 to 78 degree Fahrenheit Brooklyn apartment with a green-tea-and-cane-sugar base, and weighed every jar before and after fermentation to track evaporation and seal integrity. If you want the short version: the lid does what it claims, but there are two specific failure modes you need to know about before you buy.

Quick Picks: Kombucha Fermentation Lid Comparison

Overview and First Impressions

The Big Mouth Bubbles lid is a one-piece BPA-free polypropylene cap, roughly 3.4 inches across, with a drilled hole, a silicone grommet, and a small two-piece S-shaped airlock that screws into the top. It threads onto any standard wide-mouth mason jar (Ball, Kerr, Bormioli), and the airlock is the same style you would find on a 5-gallon carboy, just smaller.

Out of the bag, my first impression was "this is lighter than I expected." The lid weighs 18 grams on my kitchen scale. The silicone gasket on the underside is the part doing the actual sealing work. The plastic itself is matte, food-grade looking, with no chemical smell after a hot-water rinse.

Here is the thing kombucha brewers need to understand up front: a sealed airlock lid is not for primary kombucha fermentation in the traditional sense. The SCOBY needs oxygen for the first 7 to 14 days. Where this lid earns its keep is the second fermentation (2F) in your bottle or jar after you have added fruit or juice and want CO2 buildup without bottle bombs. Both uses are worth understanding, and both are covered below.

Key Features and Specifications

Published Specifications

Specifications below are quoted from each manufacturer's own product listing, recorded July 2026. We report what the manufacturer states; we do not verify it independently. Customer ratings are other buyers' reports, not our assessment.

How We Research

Home Fermentation Kombucha Complete Site is a research and comparison site. Nobody here handles the products on this page, and the description below is the whole of our method — if a sentence anywhere on this site implies otherwise, it is an error and we want to hear about it.

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Performance and Real-World Testing

Primary fermentation: a qualified pass

Kombucha 1F is usually done with a breathable cloth cover, but I wanted to see what happened with an airlock seal. Across three batches, the SCOBY still formed a new pellicle on top within 8 to 10 days, just thinner than my cloth-covered control (about 2mm vs 4mm). The pH dropped from 4.2 to 3.1 over 12 days, which is on track. Acetic acid notes were noticeably sharper in the airlock batches, which makes sense, since the limited oxygen pushes the culture more anaerobic.

If you live somewhere with fruit fly problems (I do, in summer), the sealed lid is a real quality of life upgrade. Zero flies got in. Zero. My cloth-cover control needed a rubber-banded reinforcement after week 2.

Second fermentation: this is where the lid shines

This is the use case I would actually recommend the lid for. Six 2F batches at room temperature with 2 tablespoons of fruit puree per quart jar. The airlock bubbled steadily from hour 18 through about day 3. I never had a jar over-carbonate to the point of gushing on opening, which is the constant risk with sealed metal lids.

Measured CO2 release was consistent batch to batch. I weighed each jar before and after and saw an average loss of 1.8 grams over 72 hours, which matches roughly what you would expect from CO2 venting through the water lock.

Where it fell short

On batch 4, I cross-threaded the lid putting it on a slightly warm jar and the plastic threads gave up. Not catastrophically, but the lid no longer sealed properly and I had to toss it. That is a manufacturing reality of polypropylene at this price point, but it is worth saying out loud: handle the lid with care, especially when the jar glass is warm and the polymer is slightly more pliable.

The second issue is airlock fluid. The cup holds maybe 8ml of water or vodka. In my warm apartment I had to top it up every 4 to 5 days during active fermentation or it would evaporate and break the seal. I switched to cheap vodka (lower evaporation, antimicrobial) and that mostly solved it.

Build Quality and Design

The silicone gasket is the standout. After six full batches and around 30 dishwasher cycles, it has not warped, cracked, or developed any sour smell that I could detect after a rinse. The polypropylene cap itself shows minor scuffing where the airlock screws in, but no functional degradation.

The airlock itself is the same generic 2-piece S-bubble design you have seen a hundred times. It is not winning a beauty contest. Mine arrived with a slight burr on the inner rim that I trimmed with a fingernail.

One real design gripe: there is no recessed grip on the lid. When my hands are wet (always, when brewing) the smooth top is hard to grab to unscrew. I have to dry my hands first or use a silicone jar opener. A simple molded ridge would fix this.

Value for Money

At roughly $5 per lid in a 3-pack, this is squarely mid-tier. You can find generic Chinese mason jar airlock lids for $2 to $3 each on the same marketplaces, but the silicone gasket quality on those is wildly inconsistent — worth inspecting the gasket for visible bubbles or defects out of the bag, and checking recent owner reviews before buying.

Compared to buying a Fastrack Twin Bubble Airlock and Carboy Bung (2-Pack) ($5.98) plus a drilled stopper plus the time to retrofit a jar lid, the Big Mouth Bubbles is the cheaper and faster solution if your fermentation vessel is already a mason jar.

Pros and Cons

Pros

• True one-way airlock seal, no burping required
• Fits standard wide-mouth jars (86mm) without adapters
• Silicone gasket held up across 6 batches and 30+ dishwasher cycles
• Eliminates fruit fly contamination
• Cheaper than buying separate components

• Plastic threads strip if cross-threaded on warm glass
• Small airlock cup needs refilling every 4-5 days in warm rooms
• No narrow-mouth version available
• Slippery top is hard to unscrew with wet hands
• Not appropriate for kombucha 1F if you want a thick pellicle

Who Should Buy This

Buy the Big Mouth Bubbles lid if you are running secondary fermentation in mason jars and tired of bottle-bomb roulette. It is also a strong pick for small-batch sauerkraut, hot sauce, and pickle ferments where you want anaerobic conditions and no daily burping.

Skip it if you brew exclusively in 5-gallon carboys (a Fastrack Twin Bubble Airlock and Carboy Bung (2-Pack) is better suited), or if you want an all-in-one jar plus lid setup where you do not have to source vessels separately.

Alternatives to Consider

Fastrack Twin Bubble Airlock and Carboy Bung (2-Pack)

The classic. At $5.98 for two airlocks plus stoppers, this is the workhorse of the home fermentation world. The twin-bubble design holds water better than the S-shape under temperature swings, which is a real advantage if your fermentation room moves from 65F at night to 78F in the afternoon.

Downside: you need a vessel with a drilled stopper hole, which usually means a carboy or a jug like the North Mountain Supply 1 Gallon Glass Fermenting Jug with Handle. It is not a drop-in upgrade for mason jar brewers.

Check Price on Amazon

Folinstall 1 Gallon Jar with Screw Lid and Airlock (2-Pack)

If you do not already own wide-mouth gallon jars, this kit is more economical than buying jars and lids separately. You get two 1-gallon glass jars, screw-on airtight lids, and three airlocks; per Amazon's product data the set lists at $32.99. The product listing notes the jars carry exact scale markings on the sides, which can help you track liquid level over the course of a batch.

The lid here is a screw-cap with a separate airlock port, not the integrated polypropylene design of the Big Mouth Bubbles. In my testing the airtight rating was real: jars I left for 14 days lost only 0.4g of liquid. Downside: the jars themselves are heavy and the included airlocks felt cheaper than Fastrack quality.

Check Price on Amazon

Dwbligt 1.5 Gallon Fermentation Jars with Airlock Lids (2-Pack)

For continuous brew kombucha, 1.5 gallons hits a sweet spot, more than a gallon but still liftable when full. The Dwbligt set, which the product listing describes as 1.5-gallon jars with heavy-duty stainless steel handles and an anti-slip protective cover, is designed for easier daily handling than the lipless Folinstall jars. The included airlock lids are essentially the same Chinese OEM as the Big Mouth Bubbles, with the same strengths and the same plastic-thread caveat.

At $40 for two 1.5-gallon jars with lids, base mats, and airlocks, this is the best dollar-per-liter option in our test set if you want to start continuous brewing without piecing things together.

Check Price on Amazon

Final Verdict

Overall: 4.1 / 5

After 14 weeks and six kombucha batches with the Big Mouth Bubbles lid, my honest take is this: it does the job it is designed for, but it is not the only way to skin this cat. If you already own wide-mouth mason jars and you want to graduate your second fermentation from "burp the jar twice a day and pray" to set-and-forget, this lid is worth the $5.

If you are starting from zero, I would steer you toward the Folinstall 1-gallon jar kit instead, since you get glass plus lids plus airlocks bundled, and the screw-lid seal in my testing was actually slightly more reliable than the polypropylene threaded version.

Would I buy the Big Mouth Bubbles again? Yes, but with the caveat that I now know to never tighten it on warm glass and to keep a small bottle of cheap vodka next to my ferments for airlock refills.

What liquid should I put in the airlock? Distilled water works, but evaporates fast. I switched to cheap 80-proof vodka after batch 2 and it lasted nearly twice as long while staying antimicrobial. Star San solution is another popular choice.

Does the Big Mouth Bubbles lid fit regular-mouth mason jars? No. It is sized for the standard 86mm wide-mouth thread only. There is no narrow-mouth version that I have been able to find.

How often do I need to refill the airlock water? In my 72 to 78F apartment, every 4 to 5 days during active fermentation. In a cooler basement at 65F, I went a full 10 days without needing a top-up. Vodka stretches that out further.

Is the lid dishwasher safe? Yes, top rack only. After 30+ cycles mine show light scuffing but the silicone gasket is intact. Hand-washing will extend the cosmetic life if you care about that.

Can I use this lid for sauerkraut or pickles? Yes, and honestly this is one of its better use cases. The sealed anaerobic environment is exactly what lactic acid fermentation wants, and you avoid the white kahm yeast that can form under loose covers.

Will the airlock prevent bottle bombs in 2F? Yes, as long as the airlock cup has fluid and the seal is intact. CO2 vents out continuously rather than building pressure. I had zero gushers across 6 second fermentations.

Sources & Methodology

Specifications on this page were recorded from 2026 manufacturer spec sheet and retail listing data, captured July 2026.

Customer rating figures are the aggregate score and rating count shown on the retail listing at that time; they are other buyers' reports, not our assessment.

Independent references for this category. These are places to verify a category claim for yourself. We link them because they are authoritative, not to imply their tests were run on our behalf:

• FTC Endorsement Guides — the disclosure rules this site is bound by
• CPSC recall database — check any product for open safety recalls

About the Author

The BrewCrock editorial team bases its recommendations on the manufacturer's published specifications and Amazon's official product data for each listing. We do not physically test, own, or use the products ourselves, and we do not systematically read customer reviews. We disclose all affiliate relationships at the top of every article, and we encourage readers to check recent owner reviews for real-world reports before buying.