8 Airlock and Tubing Accessories for Preserving in Fermentation Crocks

Walking into a cellar filled with the rich, tangy aroma of bubbling sauerkraut or fermenting cider is one of the most rewarding moments of the harvest season. However, keeping those ferments safe from wild molds and spoilage bacteria requires precise control over the air entering and leaving your crock. The right combination of airlocks, bungs, and tubing creates a reliable one-way street that lets carbon dioxide escape while keeping oxygen and pests out.

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Why Airlocks and Tubing Matter in Fermentation

Fermentation is a delicate dance between beneficial microbes and destructive spoilage organisms. When preserving a bumper crop of cabbage, cucumbers, or orchard fruit, the goal is to encourage lactic acid bacteria or yeast to thrive. These friendly organisms require an anaerobic—or oxygen-free—environment to do their job properly, which is where a secure seal becomes absolutely critical.

Without a proper venting system, a sealed fermentation crock can quickly turn into a pressurized hazard. Carbon dioxide gas builds up rapidly during the active phase of fermentation, requiring a safe way to escape without letting outside air back in. A simple cloth cover might keep fruit flies out, but it allows oxygen to contact the surface, leading to the growth of unsightly and off-tasting Kahm yeast or destructive mold.

Using dedicated airlocks and tubing turns any standard crock or carboy into a secure, self-regulating preservation chamber. This setup minimizes hands-on maintenance, allowing you to leave crocks to ferment for weeks or months with minimal intervention. Investing in these small accessories ensures that your hard work in the garden doesn’t end up in the compost pile due to a simple sealing failure.

3-Piece Airlock – Brewer’s Best Three-Piece Airlock

An airlock is the primary defense system for your fermenting crock, acting as a physical barrier against airborne contaminants. It allows carbon dioxide to escape through a water barrier while preventing oxygen, wild yeasts, and dust from entering the vessel.

The Brewer’s Best Three-Piece Airlock is a highly practical choice because of its simple, easily cleanable design. Unlike molded one-piece designs, this airlock can be completely disassembled into three separate parts, making it incredibly easy to scrub out any krausen or residue that bubbles up during an active ferment. The clear, food-grade plastic allows you to monitor the bubbling activity at a glance from across the room.

• Disassembly: Three separate pieces (body, floating cap, top lid)
• Stem Diameter: Standard 3/8-inch outer diameter
• Liquid Capacity: Requires about 1 to 2 tablespoons of water or sanitizer
• Tip: Fill the chamber to the marked line with a food-safe sanitizer or cheap vodka rather than plain tap water to prevent mold growth inside the airlock itself.

This airlock is ideal for small-batch fermenters who value easy cleanup and want a clear visual indicator of fermentation progress. It is less suited for high-volume, extremely violent ferments where a blowoff tube is required to handle excessive foam.

S-Bubble Airlock – Fermonster S-Shape Bubble Airlock

When a ferment slows down, changes in temperature or atmospheric pressure can create a vacuum, pulling the liquid inside your airlock backward into the crock. An S-shape airlock prevents this suck-back effect, protecting your ferment from contamination.

The Fermonster S-Shape Bubble Airlock features a double-chamber design that keeps the liquid barrier intact even when pressure shifts. The sturdy construction resists cracking when inserted into tight bungs, and the narrow chambers require very little liquid to create a secure seal. It is particularly useful for long-term aging where temperature fluctuations in a cellar or pantry are common.

• Design: Two-chamber vertical loop
• Material: High-clarity, BPA-free plastic
• Suck-Back Prevention: Built-in chambers equalize pressure safely
• Tip: Cleaning this airlock requires a bit of patience, as you cannot physically scrub the inside of the loops; flushing it with warm water immediately after use is crucial.

This is the perfect choice for long-term preservation projects like traditional crock pickles or fermenting cider where temperature swings might cause pressure shifts. It is not recommended for highly active, pulpy ferments that are prone to foaming over, as the narrow channels can clog easily.

Silicone Grommet – Home Brew Ohio Silicone Grommet

To use an airlock with a modern fermentation crock lid or a DIY plastic bucket lid, you need an airtight seal around the entry hole. A silicone grommet sits inside the drilled hole, gripping both the lid and the airlock stem to prevent gas leaks.

The Home Brew Ohio Silicone Grommet is molded from food-grade, high-durability silicone that resists cracking and drying out over time. Unlike cheap black rubber grommets that can degrade and leave black residue on your fingers, these translucent silicone pieces remain pliable through years of use. They provide a snug, reliable grip on standard 3/8-inch airlock stems.

• Required Hole Size: Fits a standard 1/2-inch drilled hole
• Inner Diameter: Designed for 3/8-inch airlock stems
• Material: Food-grade, heat-resistant silicone
• Tip: Wetting the airlock stem with a little sanitizer or water makes it slide through the tight grommet much easier without tearing the silicone.

This accessory is essential for anyone converting a standard crock lid or food-grade bucket into a fermentation vessel. It is not necessary if you are using traditional water-seal stone crocks that do not utilize drilled lids.

Silicone Bung – FastFerment Predrilled Silicone Bung

For traditional crocks with narrow openings or glass carboys, a tapered bung is needed to plug the neck and hold the airlock. The bung must compress slightly to form a hermetic seal against the smooth inner walls of the vessel.

The FastFerment Predrilled Silicone Bung is an excellent upgrade from standard rubber stoppers. Made of food-grade silicone, it does not absorb odors or flavors from pungent ferments like garlic or kimchi, and it can be boiled for complete sterilization. The predrilled center hole is perfectly sized to hold an airlock or a blowoff elbow securely without slipping.

• Size: Standard #3 size (fits openings roughly 1 inch to 1-1/4 inches in diameter)
• Material: 100% food-grade silicone
• Texture: Slightly tacky surface prevents the bung from slipping out of wet glass necks
• Tip: Always dry both the inside of the vessel neck and the outside of the bung before inserting to prevent the stopper from slowly popping back out under pressure.

This bung is a must-have for fermenters using glass jugs, carboys, or narrow-mouthed ceramic crocks. It is not suitable for wide-mouth mason jars or crocks that require flat, wide lids.

Blowoff Tubing – Northern Brewer Vinyl Tubing

During the first few days of a vigorous ferment, thick foam (krausen) can rise rapidly and clog a standard airlock, potentially blowing the lid off your crock. A blowoff tube replaces the airlock, routing the excess foam safely out of the vessel and into a jar of sanitizer.

Northern Brewer Vinyl Tubing is thick-walled, food-grade, and highly flexible, making it ideal for routing gas and foam away from your fermentation area. It resists kinking even when bent at sharp angles, ensuring a continuous, unobstructed path for escaping pressure. The clear walls allow you to see exactly what is moving through the tube, making it easy to spot blockages before they cause a mess.

• Dimensions: 5/16-inch inner diameter, 7/16-inch outer diameter (fits standard 3/8-inch airlock stems)
• Material: Clear, food-grade PVC vinyl
• Temperature Limit: Not suitable for boiling liquids, but handles warm sanitizing solutions well
• Tip: Soak the end of the tubing in hot water for a few seconds to soften the vinyl before stretching it over a plastic fitting or airlock body.

This tubing is crucial for backyard fermenters handling highly active, sugary ferments like fruit wines, ciders, or large batches of kimchi. It is unnecessary for slow, cool ferments that produce minimal foam.

Auto-Siphon – Fermtech Auto-Siphon 3/8 Inch

Once your ferment is complete, you need a way to transfer the liquid—whether it is brine, cider, or vinegar—into bottles or storage jars without disturbing the sediment at the bottom of the crock. Pouring directly from a heavy crock is messy and introduces oxygen, which ruins the flavor.

The Fermtech Auto-Siphon 3/8 Inch uses a simple pump action to start a siphon instantly without requiring any unsanitary mouth-suction. It features a removable tip that sits slightly elevated off the bottom of the crock, allowing you to draw clear liquid while leaving the yeast cake and vegetable sediment behind. The single-stroke design is incredibly reliable and easy to operate with one hand.

• Tubing Compatibility: Requires 5/16-inch or 3/8-inch inner diameter vinyl tubing
• Length: 15 inches long, ideal for standard crocks and 1-to-5 gallon carboys
• Material: Food-grade, acrylic outer sleeve and inner piston
• Tip: Never sanitize this siphon with boiling water, as the high heat will warp the acrylic outer tube and ruin the airtight seal of the internal gasket.

This tool is indispensable for anyone fermenting liquids or wet vegetable ferments where separating the liquid from the sediment is key. It is not useful for dry, packed ferments like shredded sauerkraut.

Tubing Clamp – Kegco Plastic Tubing Pinch Clamp

When siphoning liquid out of a crock, you often need to pause the flow to switch between bottles or jars. A tubing clamp allows you to restrict or completely stop the liquid flow instantly with a simple squeeze, preventing sticky spills.

The Kegco Plastic Tubing Pinch Clamp is a lightweight, rust-proof solution that can be operated easily with one hand. Unlike metal clamps that can pinch too hard and permanently deform your vinyl tubing, this plastic clamp distributes pressure evenly. Its ratcheting mechanism locks securely in place, allowing you to walk away from a closed line without worrying about slow leaks.

• Material: High-strength, non-corrosive plastic
• Sizing: Fits tubing with an outer diameter up to 1/2 inch
• Operation: Quick-release latch for instant reopening
• Tip: Slide the clamp onto the tubing before attaching both ends of your siphon setup so you don’t have to disassemble the line later.

This is an essential accessory for anyone bottling fermented beverages, vinegar, or hot sauces. It is not needed if you only perform dry-pack ferments that do not require siphoning.

Airlock Brush – Fermentaholics Cleaning Brush

Fermentation residue is sticky, sugary, and prone to harboring mold if not cleaned immediately. Because airlocks and small fittings have narrow, hard-to-reach chambers, standard kitchen sponges cannot clean them effectively.

The Fermentaholics Cleaning Brush is specifically designed with a long, flexible wire handle and stiff nylon bristles to reach deep into the bends of airlocks and tubing. The protective tip prevents the wire from scratching the soft plastic interiors, which is crucial because scratches can harbor bacteria. It is durable enough to withstand repeated scrubbing with hot water and heavy sanitizers.

• Length: 12 inches long with a narrow 1/4-inch brush head
• Bristle Material: Food-grade, stiff nylon
• Handle: Flexible galvanized wire that can bend around curves
• Tip: Run the brush through your vinyl tubing while submerged in warm soapy water to easily push out any stubborn sediment.

This brush is a vital maintenance tool for any hobbyist using airlocks, blowoff tubes, or siphons. There is really no substitute for a narrow brush when it comes to keeping these small accessories clean.

How to Set Up a Blowoff Tube for Active Ferments

When setting up a blowoff tube, start by choosing a clean, sanitized length of vinyl tubing that fits snugly over your airlock’s center post or directly into your bung. Place your fermentation crock on a sturdy surface where any potential overflow won’t ruin your flooring, such as a plastic tray or utility sink.

Submerge the free end of the tubing into a half-filled jar of sanitizing solution or water, ensuring the end stays fully underwater. This jar must be positioned lower than the top of your fermentation crock to prevent gravity from pulling the liquid back into your ferment.

As the ferment peaks, gas and foam will travel up the tube and bubble safely into the jar, keeping your crock pressurized and protected. Once the active bubbling slows down after a few days, you can safely swap the blowoff tube for a standard water-filled airlock.

Cleaning and Sanitizing Your Fermentation Tubing

Proper sanitation is the difference between a delicious ferment and a spoiled batch. Vinyl tubing is particularly susceptible to harboring wild yeast and bacteria if organic matter is allowed to dry inside the line. Always rinse your tubing with warm water immediately after use to flush out any loose sediment before it hardens.

To sanitize, submerge the tubing in a food-safe, no-rinse sanitizing solution for the recommended contact time. Avoid using boiling water on standard vinyl tubing, as this can cause the plastic to lose its structure, turn cloudy, and kink easily during future uses.

Hang the tubing over a hook or door frame to air dry completely before storing it away. Storing damp tubing in a closed drawer is a recipe for mold growth, which will ruin the line and require you to replace it entirely.

Choosing the Right Setup for Your Preserving Needs

Selecting the right accessories depends heavily on the scale of your harvest and the types of ferments you prefer. For heavy, dense vegetable ferments like sauerkraut or fermented carrots, a simple silicone grommet, a flat lid, and a three-piece airlock are usually all you need. These ferments produce steady gas but very little foam, making complex blowoff setups unnecessary.

If you are venturing into liquid ferments like cider, vinegar, or fermented hot sauces, your needs will shift toward siphons and flexible tubing. These active ferments require the security of a blowoff tube during the initial stages, followed by an S-shape airlock to prevent oxygen suck-back during long-term aging.

Ultimately, building a versatile kit of high-quality, food-grade silicone and vinyl accessories saves time and prevents crop spoilage. Start with the basics, keep your gear meticulously clean, and expand your tool kit as your homestead preservation projects grow.

Equipping your home preservation setup with the right airlock and tubing accessories takes the guesswork out of fermentation. By protecting your hard-earned harvests from oxygen and contaminants, these simple tools ensure consistent, delicious results batch after batch. With a small investment in quality gear, you can confidently preserve the seasonal bounty of your small-scale farm for months to come.