Have A Question?|info@fermentaholics.com

Rubber Stopper – Bung Stoppers for Fermentation – Home Brew – Beer, Cider, Wine Making


Rubber Stopper For Fermentation

  • Non drilled Solid Rubber Stoppers Available Here
  • Creates an airtight seal keeping oxygen out
  • Food grade rubber
  • #2,  #5.5, #6, #6.5, #7, #7.5, # 10, # 10.5, # 11
  • Rubber Stopper Bung Sizing Chart
Share this


Rubber Bung Stoppers for Fermentation

Rubber bungs are used when fermenting to completely seal or create an airtight barrier between the airlock and opening of your fermenter.
Depending on your needs you have two options: Solid Rubber stoppers create a complete seal while drilled rubber stoppers have a hole drill into them which fits a standard size airlock or a small blow-off tube.

Rubber stoppers come in assorted sizes and are required to create an airtight seal in most fermentation. Our food-grade stoppers are made of solid rubber. The rubber bung is tapered for a better seal and holds the airlock securely in place. The curved lip also stops the bung from accidentally sliding into your fermenter. These stoppers have many uses in fermentation which include beer brewing, cider, and winemaking, just to name a few.

How does the rubber stopper work?

Plug the stopper into the mouth of your carboy or fermenter. This will create an airtight seal that prevents oxygen contact during fermentation.

What size rubber stopper do I need for my fermenter?

Stoppers come in various sizes and are sized by number but what do these numbers mean? To determine the correct stopper size, measure the diameter of the mouth of your carboy or fermenter, and compare it to the rubber stopper size chart below. This chart will help you quickly determine which stopper you need by most popular brewing equipment and provides a diameter for each stopper style in inches.

Stopper Type Compatible With:

No. 2 Stopper fits standard beer and wine bottles.
No. 5 Stopper fits Big Mouth Bubbler® EVO 2 w/screw-on lid (older EVO 2 models) & Little BMB.
No. 6 Stopper Drilled or Solid fits standard 1 Gallon Jugs.
No. 6.5 Stopper Drilled or Solid fit Glass carboys, Big Mouth Bubbler® plastic (5 or 6.5 gallons), or EVO 2 w/ Universal Lid. The ideal fit is the 6-gallon carboy.
No. 7 Solid Stopper fit 5 Gallon glass carboys
No. 10 Solid Stopper fits Bubbler® 5 or 6 gallon
Small Universal Stopper – Drilled or Solid Glass Carboys (3, 5, 6, 6.5), Big Mouth Bubbler® Plastic 5 or 6.5-gallon or EVO 2 w/ Universal Lid.
Medium Universal Stopper – Drilled or Solid Bubbler® 5 or 6-gallon.


We are DEDICATED to producing the highest quality, affordable products. Our highly trained staff is committed to upholding the integrity and putting the customers first.


The Fermentaholics support team is a fellow group of fermentation fanatics. We LOVE to talk about fermentation and help each other learn, grow, and experiment with different techniques and flavors. Reach out to have any of your fermentation questions answered! By purchasing our products, you are instantly a part of an ever-growing community of fermenters like yourself. Welcome to our fermenting family!

Additional information

Weight .2 lbs
Dimensions 1 × 1 × 1 in
Solid Rubber Stopper

# 2 Solid Rubber Stopper, # 5 Solid Rubber Stopper, #5.5 Solid Rubber Stopper, # 6 Solid Rubber Stopper, # 6.5 Solid Rubber Stopper, # 7 Solid Rubber Stopper, # 7.5 Solid Rubber Stopper, # 10 Solid Rubber Stopper, # 10.5 Solid Rubber Stopper, # 11 Solid Rubber Stopper


There are no reviews yet.

Be the first to review “Rubber Stopper – Bung Stoppers for Fermentation – Home Brew – Beer, Cider, Wine Making”

Go to Top