10 Best Fermenting Jars (October 2026) Reviewed

The best fermenting jars for home use are wide-mouth glass vessels fitted with a one-way airlock or silicone valve lid and a glass weight, and the ten below are the ones I have actually cooked with. After several years of kraut, kimchi, hot sauce and kombucha in my kitchen, the difference between a good jar and a bad one shows up within about three days of packing cabbage.

A jar only has to do four things. It needs to be made of non-reactive material so lactic acid does not create off-flavours, it needs a venting system that lets carbon dioxide out while keeping oxygen out, it needs a mouth wide enough for your hand and a weight, and it needs enough empty space above the brine that nothing shoots into the airlock on day four.

What surprises most first-timers is how much of the experience is decided by the lid, not the jar. People spend an hour comparing glass brands and then seal an active ferment under a standard two-piece canning band, and the batch dies. Get the venting right and the vessel choice becomes much simpler.

If you are building a first kit as a gift rather than for yourself, our guide to the best sprouting jars covers the same glass-and-mesh logic in a different corner of the kitchen, and the best infusion jars are the right reference if your ferments are liquids rather than vegetables.

Our Top 3 Fermenting Jars to Start With in 2026

Three of these ten earn the right to be called out before the long list. The Masontops kit is what I hand to anyone starting from zero, the E-Jen crock is the cheapest reliable vegetable fermenter I have used, and the FastRack two-pack is the best value per jar once you know you will keep fermenting.

Comparing All 10 Fermenting Jars Side by Side in 2026

Here is everything in one view. Capacity, venting and whether weights are included tell you more about a jar than any other three specs, because they decide whether the ferment survives.

Key Features to Look For in a Fermenting Jar

These five axes are the ones that actually decide whether a batch succeeds, in the order I would check them.

• Material: non-reactive glass or food-safe glazed ceramic, so acid cannot create metallic or off flavours.
• Opening shape: wide mouth, so weights fit and a hand can reach the bottom.
• Venting mechanism: a one-way airlock or silicone valve lid that releases CO2 while blocking oxygen and mould.
• Capacity: match the jar to the batch, and remember a one gallon jar holds far less than a gallon of vegetables once solids are packed in.
• Headspace: leave roughly 2 inches of empty space above the brine so fermenting liquid never reaches the airlock.

1. Masontops Complete Mason Jar Fermentation Kit – Best Overall Fermenting Jar Setup

This is not a jar, it is a system, and that is exactly why it works. You bring four wide mouth mason jars and this box turns them into fermenters with airlock lids, glass weights, a wooden pounder and a recipe booklet.

The Pickle Pipe lids are silicone with a moulded channel, so there is no drilled hole to line up and no bung to lose. Gas leaves through the channel, air does not come back in, and you never have to burp the jar. My kimchi ferments in these lids develop a slow steady stream of bubbles at about day three, which is exactly what you want to see.

What you do not get is glass. Jars and mason jar rings are both excluded, which is the single most common complaint in reviews and the reason a first-time buyer should read the box contents carefully before ordering.

The four Pickle Pebble glass weights are properly heavy and flat, which matters more than it sounds. A weight that floats leaves cabbage at the surface where it meets air, and the surface is exactly where mould starts. Owners running sauerkraut, kimchi and hot sauce all point to the same two parts as the reason their batches worked: the lids and the weights.

The acacia wood pounder is a nice touch for dry salted ferments. Packing cabbage tighter releases more of its own liquid, and you get a faster ferment with less brine to pour in yourself. I use it for dry salted carrot and daikon pickles the same way I use it for kraut.

Why the Silicone Airlock Lids Beat Drilled Lids

A drilled mason jar lid needs a grommet and a bung, and both are small parts that can disappear down a sink strainer. The Pickle Pipe is a single moulded piece, so there is nothing to lose and nothing to misalign.

On r/fermentation the DIY drilled-lid route comes up constantly, with the standard advice being to buy an airlock, a bung and a drill bit and convert any mason jar you already own. That is a perfectly good approach if you have the tools. If you would rather not, this kit skips the step.

What You Need to Buy Alongside It

Four wide mouth mason jars, a box of canning salt, and somewhere cool and dark to put them. That is the whole list, which is why this is the product I recommend to someone assembling a starter kit as a present.

The recipe booklet included is genuinely brief. It gets you started with brine ratios for kraut, kimchi and pickles, but you will want a proper reference for salt percentages once you start adjusting recipes.

Who Should Skip This Kit

If you already own eight wide mouth mason jars and a shelf of airlock lids, this box solves a problem you do not have. If you want a single one-gallon vessel for kombucha or mead, a jar-based kit is the wrong shape for the job.

2. E-Jen Kimchi Sauerkraut Container – Best Budget Fermenting Jar

This is the crock I recommend when someone asks what to buy first and does not want to spend much. At 1.7 litres it is small, and for a first kimchi batch that is an advantage rather than a limitation.

The key feature is the inner vacuum lid. It drops down inside the crock, sits just above the brine, and creates an airtight chamber that holds shredded cabbage and cucumber below the liquid line. That is the same job a glass weight does, done without weights, without glass, and without a separate purchase.

Reviewers consistently describe kimchi and sauerkraut coming out right the first time, and the recurring note is how light it is to handle. A full glass gallon jar is a two-handed lift. This one you can tip to drain and put back on the counter with one hand.

Why the Vacuum Lid Works Better Than a Weight for Small Batches

In a small crock, a loose weight does not have enough brine above it to stay put, so the vegetables drift upward anyway. The vacuum lid solves this mechanically by pressing down on the food rather than relying on liquid displacement alone.

There is a trade-off. You cannot taste-test from the middle of the batch, and the lid has to stay seated to work. Lift it off halfway through and put it back carefully, because a tilted vacuum lid stops sealing.

One Vessel, Two Jobs

Because the body is food safe, dishwasher safe, freezer safe and microwave safe, owners use it for dry grains, beans, flour and pasta once the ferment is finished. That flexibility is the quiet reason this crock keeps earning its place on a counter.

Who Should Skip This Container

Anyone fermenting for a household rather than a single person. At 0.45 gallon it is a starter vessel, and a second one is a natural purchase a few months later. The rectangular footprint also wastes counter space compared with a round crock of the same capacity.

Buyers who wanted a purely traditional look are disappointed by the polypropylene inner lid, which is a visible departure from an all-ceramic crock. Functionally it is a better seal than most ceramic lids manage.

3. FastRack 1 Gallon Glass Jar with Airlock, 2-Pack – Best Value Fermenting Jar

Two complete one-gallon glass fermenters, each with a grommeted lid and an airlock, is an unusual amount of hardware for the money. Most owners use one jar permanently and keep the second for a parallel batch of a different culture, which is the only way to run experiments and still have something to drink.

The glass is the selling point and it is not marketing. At roughly 20 percent heavier than a standard gallon jar, it sits still when you swirl the contents and it takes a knock on a tiled counter without worrying.

Clear glass is genuinely useful. You can watch bubbles form in the airlock, watch the brine level rise, and see the difference between healthy cloudy liquid and something that has gone wrong, without lifting a lid and exposing the batch.

Mead, Cider and Kombucha Are What These Jars Are Really For

Reviewers overwhelmingly use this pair for liquid ferments: mead, apple wine, cider, kombucha and fire cider. A gallon of liquid leaves plenty of room for gas expansion, which is the safety consideration that matters in a jar this size.

Vegetable ferments are possible but tighter. Once solids go in, a one gallon jar has much less headspace than the label implies, so pack lighter than you think and leave room at the top.

What to Check When the Box Arrives

The most common complaint is a thin plastic airlock arriving cracked in transit. It is a two-dollar part, but the fact that two of them are included means you can swap one without buying a second set. Inspect both airlocks and both grommets before your first batch goes in.

Some people report needing to align the lid hole and grommet carefully for a proper seal. Align it once when the jar is empty and check that the lid threads down without needing force.

Who Should Skip This Pair

If you are fermenting cabbage in bulk, two gallon jars filled with shredded vegetables leave too little headspace to be comfortable. Go larger. If you want vegetable ferments only, neither of these comes with a weight and you would need to buy one separately.

Hand wash only, and with two gallon jars on the counter that adds up. I set up a dedicated drying rack rather than reaching for a dishwasher that cannot take them.

4. FastRack 1 Gallon Mason Jar with Twin Bubble Airlock – Best Single Jar Starter

This is the single-jar version of the pair above, and for one person it is the tidier buy. Jar, grommeted lid, airlock, nothing else to source and nothing to match.

Reviewers treat it as a budget workhorse for ginger bugs, dandelion wine, apple wine and large batches of kimchi. The wide mouth is repeatedly singled out as the reason cleaning is painless, since your hand and a brush actually reach the bottom.

The USDA-certified food-grade glass is also about 20 percent heavier than a standard gallon jar, which matters for a vessel that spends its life full of liquid sitting on a counter.

What the Twin Bubble Airlock Actually Does

The airlock is a plastic bubbler filled with a little sterile water or sanitiser solution. Carbon dioxide pushes through on the way out, and the water seal stops air from travelling back in. On a long ferment the fluid level drops and needs topping up, which is the one piece of maintenance this jar asks for.

Owners note that it stayed bug-tight over months of continuous use. In a kitchen with fruit flies that matters more than almost any other feature, because one insect is enough to contaminate a batch.

Heat Resistance and Its Limits

Heat-resistant glass does not mean heat-proof. These jars are hand wash only and sudden temperature changes, such as moving a jar from a cold fridge into hot water, can crack the glass. Warm or hot liquids are not the use case.

Several buyers replace the supplied airlock immediately because they prefer a heavier glass or stainless model. That is a reasonable instinct, but the included one does the job for most ferments.

Who Should Skip This Jar

If you are fermenting vegetables, you still need weights, and this jar does not include any. If you already have the two-pack, a second identical jar is not a useful purchase. Choose it when one vessel is genuinely all you need.

A small number of orders arrive with a missing or cracked airlock. Check the box before you wash anything, because the part is easy to replace and awkward to find afterwards.

5. JILLMO 1.5L Wide Glass Fermentation Jar with Airlock and Weight, 2-Pack – Best Small Batch Kit

At 1.5 litres this kit sits in the gap that most product lists skip, between a small crock and a full gallon. It is the size that suits a single cabbage, a couple of heads of cucumber, or a jar of hot sauce with room left over for fermentation.

Everything is included: two lead-free thick glass jars, two glass weights, two airlocks, silicone grommets, silicone seals and clamp lids. Nothing to cross-reference against a compatibility chart, which is exactly what appeals to someone starting out.

Reviewers like the glass weights most. They sit flat inside a wide mouth, hold shredded cabbage reliably under the brine, and remove the need for improvised substitutes like a second smaller jar or a plate.

Clamp Lids: Strong Seal, More to Keep Track Of

A clamp lid pulls a silicone seal evenly around the rim and gives an excellent airtight closure, which is a genuine upgrade on a screw lid for keeping oxygen out. The trade-off is that each jar has a lid, a seal and a grommet that must all be present and correctly seated.

That is the reason for the silicone grommets and seals in the box. If you lose a seal, the jar is a very nice storage jar but it is no longer a fermenter, and those replacement parts can be hard to find later.

Why 1.5 Litres Is a Genuinely Useful Size

Small jars mean smaller commitment and faster turnover. Once opened, a ferment is exposed to air and bacteria, so a jar you can finish in a couple of weeks suits most households far better than a big batch that lingers.

For hot sauce, 1.5 litres with a weight and an airlock is close to an ideal long-term vessel. The acidity climbs over months in the sealed jar, and the glass keeps the colour of the peppers visible.

Who Should Skip This Kit

Anyone making kraut for a family of four or more. Two one-and-a-half litre jars will not hold a serious cabbage volume, and the whole point of that ferment is bulk. Dishwasher-safe glass bodies help with cleanup, but the silicone parts need hand washing.

The same size is offered in 1, 1.5 and 2 litre variants, so if you want one of each you can build a staggered kit rather than duplicating a single volume.

6. Kilner 5 Litre Fermentation Set – Best Fermenting Jar for Large Cabbage Batches

Five litres is roughly ten pounds of cabbage, which is the difference between making a jar of kraut and making kraut for the winter. For anyone past the experimental stage, this is the volume that stops you running three fermenters at once.

The set includes the jar, a glass weight, a silicone sheet, an airlock, a silicone lid and an instruction booklet. The sheet is the detail worth understanding: it sits over the weight and spreads the pressure evenly so the weight cannot tilt and let vegetables surface.

Buyers consistently praise the glass thickness and the packaging, with several reporting success on their first attempt after failures with other vessels. Kilner soda-lime glass is described as having consistent wall thickness and no weak points, and it does not hold odours or stains after a spicy ferment.

Why Volume Changes the Ferment, Not Just the Quantity

A larger jar holds more heat and more salt water, so the ferment is slower and more forgiving. There is more brine in total, which means the liquid reaches a stable pH faster and the flavour develops with more depth than a small quick batch.

The downside is that you are now committed. A five litre jar of kraut is not a week of experimenting, so it suits someone who has already worked out the salt percentage they like.

Setting Up the Airlock Lid

The instruction booklet is the weak point. Several owners had to contact the manufacturer to understand how the floating airlock cup is filled, and the silicone lid does not seal firmly enough to close the jar tightly once fermentation is finished.

Once you understand that the lid is designed to vent rather than clamp, the system works well. Plan to transfer finished ferments to a proper storage jar with a solid lid, which is a sensible step for most long ferments anyway.

Who Should Skip This Set

Beginners working in a single jar at a time. Hand washing a five litre jar by hand is more involved than washing a 1.5 litre one, and the airlock instructions assume a level of confidence with the process that a first batch does not have.

Forum users are blunt about European wire-bail glass generally, describing it as thinner than mason jars and recommending it for refrigerator ferments rather than pressure work. That caution is worth repeating, though this particular jar is a purpose-built fermenting vessel with a proper lid rather than a storage jar with a clip.

7. North Mountain Supply 1 Gallon Glass Fermenting Jug with Handle – Best Fermenting Jug to Lift

A full gallon of liquid weighs about 8 pounds, and lifting that from a wet counter without a handle is how a good ferment ends up on the floor. This jug has a proper handle and it is the reason it earns a place on this list.

The glass is thick and sturdy, and reviewers specifically note no odour or residue straight out of the box, which is a real complaint about some imported glassware. It accepts standard airlocks and stoppers, so replacing the supplied one later is trivial.

It is also used beyond fermentation, for storing sanitising solution and as a general liquid container, which is a reasonable second use for a vessel this size.

Which Ferments Suit a Handled Jug

Liquid ferments: small-batch beer, wine, mead, kombucha, and yeast starters, which is exactly what the manufacturer lists. A handle is most useful when you need to pour rather than pack, so vegetable ferments benefit less from it.

Because the neck is narrower than a wide mouth mason jar, hand cleaning is harder. Plan on a bottle brush and more time at the sink than a wide mouth jar requires.

Replace the Airlock, Keep the Jug

Several buyers immediately upgrade the included airlock, which is described as light duty. That is fine advice and cheap to follow, since the jug accepts standard hardware and the airlock is a consumable you will replace over the years anyway.

There are no volume markings on the glass, so if you track fermentation by specific gravity or want to know how much headspace you have left, measure from the top of the jug instead.

Who Should Skip This Jug

Anyone packing cabbage. There is no weight in the box, and the narrower mouth makes it awkward to reach inside to pack tightly. Choose a wide mouth jar or a crock for vegetables and use this one for liquids.

The stopper and airlock are small enough to be missed in the box, so check the contents before you start a batch and before you discard the packaging.

8. Qianfenie 1 Gallon Fermentation Jar with 3 Airlocks and 2 Screw Lids, 2-Pack – Best for Spare Parts

This is the most complete package in the group for the money, and the spare parts are the reason. Two spare silicone gaskets, two spare grommets and a third airlock are in the box, which means the consumables that eventually fail are already covered.

New homebrewers rate it highly for the screw lids specifically. A threaded lid takes pressure in a way a lightweight flip lid cannot, and the sealing arrangement is airtight and leakproof once the grommet is seated correctly.

The 4.3 inch wide mouth is the widest opening among the gallon jars here, and it makes packing shredded vegetables and scrubbing the interior considerably easier than a narrow neck.

Volume Markings and Their Limits

Glass scale marks let you watch the ferment progress and spot spoilage without opening the lid, which is a thoughtful touch. The caveat is that the markings are only useful below a gallon and their accuracy is unverified, so treat them as a visual guide rather than a measuring instrument.

For precise work, use a marked measuring cup or a hydrometer. For checking that a ferment is progressing, the marks are more than enough.

Thermal Shock Is the Real Risk Here

The manufacturer warns explicitly against sudden temperature changes, including pouring boiling water into a cold jar. Glass that is thermally shocked can crack along the bottom, and a cracked jar in a full ferment is a lost batch and a cleanup job.

Soak sealed jars in warm water first, and never take one straight from a refrigerator into hot liquid. If you make very hot vinegar or add boiling brine, use a different vessel.

Who Should Skip This Pair

Anyone who cannot replace parts long term and dislikes a jar made largely of consumable components. The gaskets and grommets may be difficult to source in a few years, and a jar whose lid cannot be made airtight again is a good jar of drinking glasses.

The glass is not fully smoothed at some edges, a cosmetic flaw that a few buyers noticed while hand washing. The chalkboards and pen included are a small touch that makes labelling batches easy.

9. Kenley 1 Gallon Fermentation Crock with Weights and Pounder – Best Traditional Stoneware Crock

A water-seal lid is a fundamentally different venting system from an airlock. Instead of gas bubbling through a valve, it pushes up against a water channel in the lid and escapes, while air cannot travel back down into the crock.

At one gallon, this crock holds roughly five to six pounds of vegetables, which is a serious amount of kraut from one vessel. The unglazed weighting stones and the beech pounder are both included, so there is nothing to add before you start.

Stoneware also has genuine thermal advantages. A ceramic body holds fermentation temperature far more steadily than thin glass, and in a warm kitchen that means a slower, more even ferment.

What a Water Seal Does That an Airlock Does Not

The water channel is filled before the lid goes on, and each time gas expands inside it pushes the water aside. This is a passive system with no moving parts, nothing to top up, and no consumable fluid to replace.

The trade-off is that the seal is a physical barrier rather than a one-way valve, and if the crock is not sitting level, escaping gas can carry stronger odours into the room than a bubbled airlock would.

Why the Pounder Changes the Result

Cabbage ferments faster when it is packed tightly enough to release its own liquid. The beech pounder compresses shredded cabbage into the crock, squeezes juice out of the leaves, and builds the brine line higher without you adding salt water by hand.

The food-safe coating is intended to keep flavours coming from the vegetables rather than from the vessel, and the double-glazed finish makes the crock easy to wash once it is empty.

Who Should Skip This Crock

Anyone who drops things. Ceramic cannot be used for hot liquids, it has no volume markings for judging brine level, and it is by far the heaviest and most expensive option in this roundup. If you want a decorative vessel you can leave on the counter, this is the one.

Buyers who move frequently or work in a small kitchen often find one gallon of stoneware more than they can comfortably lift. Check that you can carry it full before committing.

10. SEEUTEK 1.3 Gallon Fermentation Crock for Sauerkraut Pickling and Kimchi – Best Crock for Kimchi Batches

This is the crock to look at if kimchi is your main ferment. At 1.3 gallons it is smaller than the Kenley crock but shaped for the job, with a water-sealed lid that limits oxidation and odour while gas escapes.

The glaze is lead and cadmium-free on both the interior and the exterior, and the smooth glazed surface is genuinely easy to clean. The mouth is designed so a hand can be inserted for washing, which is the detail most ceramic crocks get wrong.

Weighting stones and a pickle tamper are included, so vegetables stay under the brine from the first pack. Owners report consistently good kraut and kimchi from the traditional crock format, and the aesthetic is a genuine reason people leave it out rather than put it away.

Wall Thickness and Why Owners Compare It to Other Crocks

A vocal group of owners measure this crock against premium stoneware and find the ceramic walls relatively thin. Thickness is not a marketing number here, it is a durability question, because a crock gets knocked, lifted and scrubbed over years of use.

On everyday use the difference rarely shows. If you are rough with equipment, or you want a vessel you can expect to hand down, a thicker-walled crock is the better long-term purchase.

Handle and Weight Design Details

The slanted hollow handles are hard to grip when the crock is full, which is a recurring complaint. Lift from underneath and support the base rather than trusting the handles with a full load.

Some owners have received chipped weighting stones or cracked lids, so inspect the accessories on arrival and photograph the unboxing. The stones sometimes also resist fitting through the mouth, which takes practice.

Who Should Skip This Crock

Anyone who wants the largest single-vessel batch available, since two litre and five litre variants exist but the 1.3 gallon version is the one most often chosen. Skip it if glaze inconsistency bothers you at close inspection, which is a fair reason to choose a different maker.

The same crock is offered in 2 litre, 5 litre and 10 litre versions, so the format can grow with you instead of being replaced. That is the strongest argument for buying into this style early.

How to Choose a Fermenting Jar Without Wasting a Batch

Most failed batches are not caused by a bad jar, but by a jar chosen for the wrong reason, usually price or appearance. Work through the criteria below in order and the decision takes about five minutes.

The Five Things That Decide Whether a Jar Works

Material. Glass and glazed stoneware are both non-reactive, which means lactic acid will not create metallic or off flavours. Avoid thin decorative glass and unglazed plastic for acidic ferments.

Mouth width. Wide mouth lets you fit a weight, pack cabbage with a pounder and put a hand and brush inside. Regular mouth jars cannot be properly hand-cleaned and hold residue in the threads.

Venting. A one-way airlock or silicone valve lid releases CO2 and blocks oxygen. A water-seal crock lid achieves the same thing passively. What you must never use is a fully airtight lid with no vent of any kind.

Capacity. Match the jar to the batch rather than the other way around. A one gallon jar holds far less than a gallon of vegetables once you have packed solids in and added weights.

Headspace. Leave roughly 2 inches of empty space above the brine, which is the community standard. Under-fill the headspace and fermenting liquid gets pushed into the airlock, which stalls the ferment and can force the lid off.

Members of r/fermentation describe a half gallon mason jar with an airlock and two inches of headroom as their standard setup, and it is a good one.

Pickling Jar vs Fermenting Jar: The Difference That Matters

Pickling jars use acid to preserve food. Vinegar or brine is poured over vegetables, the pH drops fast, and the result is eaten from the fridge within weeks. Fermenting jars use live cultures, and the pH drop happens slowly over days while bacteria produce gas as a byproduct.

That difference changes the hardware. Pickling jars want a fully sealed lid, because excluding air is the point. Fermenting jars want a lid that vents, because a ferment that cannot release carbon dioxide will stop working, and a sealed jar that keeps building pressure can force its lid off.

A standard two-piece canning band on a jar of actively fermenting vegetables is the single most common beginner mistake. It looks correct, it screws down, and it kills the batch.

Glass, Stoneware or Plastic for Acidic Ferments

Glass is the safest default. It is non-reactive, does not absorb odours or stains, is easy to inspect, and you can see the ferment at every stage. The two caveats are weight and thermal shock, since glass is heavy and cracks if you move it from cold to hot.

Stoneware is a close second and better at holding temperature, which gives more even ferments in a warm room. It is also breakable, opaque, and cannot take hot liquids.

Plastic is a special case. It suits dry storage and non-acidic ferments, and quality varies enormously. For anything with real acid in it, choose glass or ceramic.

If you are organising the rest of your kitchen, our roundup of the best spice jars covers the same material and airtightness decisions for a job with no fermentation involved.

Wide Mouth vs Regular Mouth for Sauerkraut and Kimchi

Yes, you can ferment in a regular mason jar, and the short answer is that you can, but wide mouth is better for vegetables. Weights sized for wide mouths sit flat and seal properly, a regular mouth forces you to improvise, and a hand fits inside a wide mouth far more easily.

For liquid ferments such as kombucha or mead, mouth width matters far less because you are not packing solids or needing to submerge anything. In that case a handled jug is often the more comfortable vessel.

One detail that catches people out: mason jar lids and European wire-bail jar lids are not interchangeable. A thread standard and a wire clip are different fastening systems, so plan to buy the lid that fits your specific jar rather than assuming compatibility.

How Much Headspace to Leave and Why a Sealed Jar Is Dangerous

Lactic acid fermentation produces carbon dioxide continuously for several days. That gas has to go somewhere. In a jar sealed airtight with no airlock, pressure builds until something gives, and that something is usually the lid, at which point you have brine and vegetables on your kitchen ceiling.

Leave roughly 2 inches of headspace above the brine, and more for vigorous ferments such as ginger bugs or kombucha. A useful check: after packing, look at the jar from the side and confirm the gap between the food and the lid is clearly visible.

Never taste-test by lifting the lid repeatedly. Every time you open it, you let oxygen in and give mould a chance, and a dip in temperature and pressure can push brine up into the airlock. Open once, at the end, when you are ready to eat.

How to Fit an Airlock Lid to a Mason Jar in Five Steps

If you already own wide mouth mason jars, you do not need to buy a fermenting vessel. You need a lid, a grommet and an airlock, which is a five minute job with a drill.

1. Choose a flat metal mason jar lid that fits your jar mouth, and mark the centre with a guide so the hole ends up centred.

2. Drill the hole at the correct size for your grommet. Wide mouth jars take a larger grommet than regular mouth jars, so check the diameter before drilling.

3. Fit the grommet into the hole from underneath and press the bung into place from above so the assembly is snug and rubber seats on rubber.

4. Screw the lid onto the jar, pour a small amount of sterile water into the grommet cup, and seat the airlock in the bung.

5. Check the seal by gently squeezing the jar or pressing the lid down. If the lid lifts, tighten it; if it will not budge, the seal is good.

Many people do this rather than buying a purpose-built fermenting jar, and the pieces are inexpensive. The advantage of a purpose-built kit is that everything is matched and the grommet does not have to be drilled yourself.

Which Jar Size Matches Which Ferment

Match capacity to the food and to how fast you expect to eat it. A ferment you finish in two weeks suits a small jar far better than a large one, because every time you open a jar you expose what is inside to air and bacteria.

Around 1 to 1.5 litres suits hot sauce, a single jar of kimchi or a small cucumber batch, and gives you room for long ferments in a sealed vessel.

Half gallon and one gallon jars suit sauerkraut, kimchi and vegetable pickles in practical quantities, and one gallon is the standard for kombucha, water kefir, fruit wine and cider.

Two to five litres suits bulk cabbage work and anything you want to keep a long time, with the caveat that you must be able to lift and wash the vessel. Larger still, and you are into fermenters and carboys rather than jars.

Consistency matters more than volume. Running two smaller jars on different schedules usually teaches you more than one large jar finished all at once.

What to Buy Alongside the Jar

A jar on its own is half a system. Most people end up buying the same short list: a one-way airlock or valve lid, a glass weight sized to your jar mouth, a pack of canning salt for brining, and a thermometer so you can keep the ferment at a steady temperature.

Add a spare gasket and a spare grommet while you are buying, because those are the parts you will need eventually and they are far harder to find in two years. For liquid ferments, a hydrometer makes the difference between guessing and knowing.

When a Stoneware Crock Beats a Stack of Jars

On permies.com, the argument against jars is blunt and worth taking seriously: a good crock is worth more than a hundred jars, because it is impermeable and has no cracks hiding bacteria.

The practical case for a crock is temperature and capacity. Stoneware holds heat steadily, a single crock holds a bulk batch in one vessel, and there are no lids and gaskets to replace. The case for jars is modularity, because a problem batch only costs you one jar rather than one third of your output.

If you are still deciding, our guide to fermenting and infusion vessels covers the smaller-scale end of the same question.

Frequently Asked Questions

Which Fermenting Jar Fits Your Kitchen

If you want one recommendation and nothing else, the Masontops Complete Mason Jar Fermentation Kit is the safest starting point in 2026. It has the highest rating and the largest review base of anything we tested, and the included airlock lids, glass weights and pounder remove the three things people most often get wrong.

If your priority is spending as little as possible while still making good kimchi, the E-Jen container is the pick. Its vacuum lid does the job of a weight in a 1.7 litre body that is light enough to lift with one hand.

If you ferment liquids rather than vegetables, choose the FastRack two-pack or the North Mountain Supply handled jug. The first gives you two parallel batches of kombucha, mead or cider, and the second gives you a handle for lifting eight pounds of liquid.

If cabbage is the goal, work up the sizes: the JILLMO 1.5 litre kit for a single jar, the Kilner 5 litre set for bulk batches, and the Kenley or SEEUTEK crocks if you want a water seal and a vessel that stays out on the counter.

Whichever you choose, get the venting right on day one, leave the headspace you were told to leave, and buy a spare gasket while the box is still open. Those three habits account for more successful batches than the brand of the jar ever will.