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Rubber Stoppers - Drilled

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Rubber Stoppers - Drilled

SKU: 6100x

Rubber stoppers with a hole drilled in the center, perfectly sized to accept airlocks or what have you.
Product Name Price Qty
No. 5 Stopper - Drilled
No. 6 Stopper - Drilled
No. 6.5 Stopper - Drilled
No. 7 Stopper - Drilled
Size 10 Stopper - Drilled

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Rubber stoppers with a hole drilled in the center, perfectly sized to accept airlocks or what have you. All suggested "Best Fits" are for new carboys purchased from Midwest Supplies. If you've got an older carboy, jug or bottle, be sure to measure the mouth and use the dimensions provided.
Details & Instructions

Additional Information

4.9 / 5.0
33 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
It would be really helpful to make it easy to find the dimensions for the stoppers. I got a 6.5 and it was way too small for what I need. The quality seems top shelf however.
May 1, 2014
Love these!
Between all the different stopper styles these are my favorite! They are soft enough to tightly fit all openings and keep air from getting in. The key is making sure both the stopper and opening are totally dry, otherwise it'll slip out.
March 31, 2014
Make sure you check your size
I bought several of these, #7 for a 6 gallon carboy and #6 for some 1 gallon carboys. Double check the sizes you need before you order.
March 30, 2014
Air Tight
For long term aging I use these rather than drilled stoppers with air locks because Oxygen can get in through the solution in the air lock over time.
February 18, 2014
Small Batch Experiments
I use these on 2, 4, and 5 liter Erlenmeyer flasks. Since the neck sizes vary so much I need a variety of sizes. The 9.5 size has been hard for me to find, but Midwest carries it. These stoppers fit well and are much cheaper than what I was getting at my local laboratory equipment shop.
February 12, 2014
Nice Fit
The #6 drilled stopper fits great in a 1 gallon glass jug, as well as 50.7 oz apple juice containers for making cider. Nice tight seal and easy to remove. I've used both S type and 3 piece airlocks with no problems. I prefer this to screw on tops.
December 5, 2013
Rubbery smell
Solid and grips well, it wont fall down or pop up. Keep the neck and stopper dry when inserting. But it smells bad. I soak it in soap water for a week to try and get rid of that smell.
December 4, 2013
Had trouble keeping it from pushing out
I'm using one of these in my carboy right now, I'm leaning toward user error because I know these are extremely common and pretty much everyone is using them but I had trouble getting it to stay in the carboy, it could be that the carboy was wet, or the stopper was still wet from sanitizing it. To keep it from coming out I grabbed a wire hanger and bent it so that I created a latch which is keeping the stopper in place, I wrapped the wire hanger around the neck of the carboy to keep it from moving.
October 23, 2013
Works well
Get the right size and they fit carboys and better bottles. I have an assortment.
October 19, 2013
good fit
They work well on the 1 gallon jugs but be careful when inserting and removing airlocks. After being in place for fermentation, I had trouble removing without breaking my plastic s-lock.
August 1, 2013
Customer Q&A
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Browse 8 questions Browse 8 questions and 6 answers
Can you tell me what size the hole that's drilled in the stopper is?
A shopper on Apr 2, 2017
The 6.5 stopper is that for the 6.5 garboy and 10 for the 10 gallon, etc
D E on Nov 28, 2015
BEST ANSWER: Hello Dennis

here's a helpful guide to stopper sizes:

Stopper Type Compatible With:

No. 2 Drilled Stopper Standard Beer bottles

No. 5.5 Drilled Stopper Big Mouth Bubbler® EVO 2 (5 gallon

6.5 gallon & Little BMB)

No. 6 Stopper Drilled or Solid 1 Gallon Jugs

No. 6.5 Stopper Drilled or Solid Glass carboys & Big Mouth Bubbler® plastic (5 or 6.5 gallon). Ideal fit is 6 gallon carboy.

No. 7 Drilled Stopper

& 5 Gallon glass carboys

No. 10 Drilled Stopper Bubbler® 5 or 6 gallon

Small Universal Stopper - Drilled or Solid Glass Carboys (3



6.5) & Big Mouth Bubbler® Plastic 5 or 6.5 gallon

Medium Universal Stopper - Drilled or Solid Bubbler® 5 or 6 gallon
I have Better Bottle plastic carboys, both 5 & 6 gallon, and they have the same sized opening - 4.4 cm (1 3/4 inches) - which is the appropriatr stopper?
J E on Sep 12, 2016
BEST ANSWER: The Better Bottle carboys, and our similar "Bubbler" carboys will use the "Medium Universal Stopper" ( SKU 40490 ) or a #10 stopper ( SKU SD10 ) They are also available in an undrilled style. -Mike W, Midwest Supplies
What is the stopper size that fits the 6 gallon plastic carboy? some say #7 and some say #10 ?
M N on Aug 2, 2016
BEST ANSWER: If looking at The Bubbler 6 Gallon Plastic carboy, you want a #10 stopper.

If looking at our Plastic Big Mouth Bubblers or standard glass carboys, want a #7,
What size stopper fits a regular gallon jug?
J A on Jul 28, 2016
BEST ANSWER: The number 6 fits the 1 gallon jug that we sell, but different styles of jugs can ave different size openings. For these, you'll want to refer to a stopper sizing chart (you can find them with a quick google search), or let us know the diameter of your jug's opening and we can let you know which one will work for you.
what is the size of the #6 stopper?
T C on Feb 9, 2016
BEST ANSWER: No.6 stopper dimensions:

Top Diameter: 1.26"

Bottom Diameter: 1.024"

Length: 1"
Where do I find the sizes in inches or mm?
Harry D on Jan 27, 2016

We don't have that info on our site, but here's a chart that I refer to often:

Let me know if there's anything else I can help with. Cheers!

what size fits a 3 gallon carboy?
A shopper on Jul 2, 2017

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