# 6 gallon better bottle fermentation capacity **URL:** \ **Category:** Systems, Gear, & DIY\ **Created:** [September 10, 2014, 12:00am UTC](https://forum.homebrewersassociation.org/t/6-gallon-better-bottle-fermentation-capacity/17595 "2014-09-10T00:00:01Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Smilee](https://avatars.discourse-cdn.com/v4/letter/s/dfb087/32.png) [@Smilee](https://forum.homebrewersassociation.org/u/Smilee)\ **Post date:** [September 10, 2014, 12:00am UTC](https://forum.homebrewersassociation.org/t/6-gallon-better-bottle-fermentation-capacity/17595/1 "2014-09-10T00:00:01Z")
Hello fellow brewers. I’m a new brewer here, and have a silly little question.  What would you say a max fermentation capacity of a 6 gal Better Bottle would be?  In researching recipes I have seen recommended top offs of 5.25 gal or higher.  Wondering if I am ok still. Thanks in advance for your insight. ---
**Author:** ![duboman](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/duboman/32/5890_2.png) [@duboman](https://forum.homebrewersassociation.org/u/duboman)\ **Post date:** [September 10, 2014, 12:23am UTC](https://forum.homebrewersassociation.org/t/6-gallon-better-bottle-fermentation-capacity/17595/2 "2014-09-10T00:23:11Z")
At 5.25 gallons you would have adequate head space with a blow off tube but you might lose a bit of yeast as it blows out.  Even with only 5 gallons I’d still recommend a blow off tube. Remember that at the bottle tapers at the top reducing available space for krausen. ---
**Author:** ![Smilee](https://avatars.discourse-cdn.com/v4/letter/s/dfb087/32.png) [@Smilee](https://forum.homebrewersassociation.org/u/Smilee)\ **Post date:** [September 10, 2014, 12:37am UTC](https://forum.homebrewersassociation.org/t/6-gallon-better-bottle-fermentation-capacity/17595/3 "2014-09-10T00:37:28Z")
So would you say that is pretty much the max? ---
**Author:** ![duboman](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/duboman/32/5890_2.png) [@duboman](https://forum.homebrewersassociation.org/u/duboman)\ **Post date:** [September 10, 2014, 12:38am UTC](https://forum.homebrewersassociation.org/t/6-gallon-better-bottle-fermentation-capacity/17595/4 "2014-09-10T00:38:18Z")
Yup:) ---
**Author:** ![Smilee](https://avatars.discourse-cdn.com/v4/letter/s/dfb087/32.png) [@Smilee](https://forum.homebrewersassociation.org/u/Smilee)\ **Post date:** [September 10, 2014, 12:49am UTC](https://forum.homebrewersassociation.org/t/6-gallon-better-bottle-fermentation-capacity/17595/5 "2014-09-10T00:49:53Z")
Brilliant! Thanks. ---
**Author:** ![skatz](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/skatz/32/6982_2.png) [@skatz](https://forum.homebrewersassociation.org/u/skatz)\ **Post date:** [September 10, 2014, 4:48am UTC](https://forum.homebrewersassociation.org/t/6-gallon-better-bottle-fermentation-capacity/17595/6 "2014-09-10T04:48:46Z")
I put 5.25-5.5 gallons in all the time. I always use a blowoff and need it about half the time. ---
**Author:** ![reverseapachemaster](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/reverseapachemaster/32/19_2.png) [@reverseapachemaster](https://forum.homebrewersassociation.org/u/reverseapachemaster)\ **Post date:** [September 10, 2014, 1:48pm UTC](https://forum.homebrewersassociation.org/t/6-gallon-better-bottle-fermentation-capacity/17595/7 "2014-09-10T13:48:13Z")
No more than 5.2513543234321. ---
**Author:** ![stevo155](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@stevo155](https://forum.homebrewersassociation.org/u/stevo155)\ **Post date:** [September 10, 2014, 2:44pm UTC](https://forum.homebrewersassociation.org/t/6-gallon-better-bottle-fermentation-capacity/17595/8 "2014-09-10T14:44:30Z")
5.5 gallon in mine with a blowoff tube.  Some blow off more than others.  I also use Fermcap-S at the start of my boil so I don’t know if any of that carries over. The orange carboy caps and 1/2" vinyl tubing making a great blowoff setup. ---
**Author:** ![skatz](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/skatz/32/6982_2.png) [@skatz](https://forum.homebrewersassociation.org/u/skatz)\ **Post date:** [September 10, 2014, 3:48pm UTC](https://forum.homebrewersassociation.org/t/6-gallon-better-bottle-fermentation-capacity/17595/9 "2014-09-10T15:48:40Z")
I use the orange caps as well but attach the blow off to the smaller end and use 3/8". The tube will sometime get constipated and I won’t here any bubbles. It’s like the fat kid from willy wonka. I do it this way since I stick a thermowell in the later port. I also use large hose clamps with a wing nut to tighten seal it up well. ---
**Author:** ![4swan](https://avatars.discourse-cdn.com/v4/letter/4/71c47a/32.png) [@4swan](https://forum.homebrewersassociation.org/u/4swan)\ **Post date:** [September 10, 2014, 5:25pm UTC](https://forum.homebrewersassociation.org/t/6-gallon-better-bottle-fermentation-capacity/17595/10 "2014-09-10T17:25:21Z")
A number 10 drilled stopper will work for a blow off too. The 3/8" tube will sometimes get clogged like Steve said.  A few years ago I bought a drilled No. 10 with a 1/2" hole which works better.  Northern Brewer sells it as a Blowoff Assembly for PET  Fermenters.  If you use StarSan as a sanitizer, the stopper gets a little slick and likes to pop out until it dries. ---
**Author:** ![duboman](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/duboman/32/5890_2.png) [@duboman](https://forum.homebrewersassociation.org/u/duboman)\ **Post date:** [September 10, 2014, 5:28pm UTC](https://forum.homebrewersassociation.org/t/6-gallon-better-bottle-fermentation-capacity/17595/11 "2014-09-10T17:28:56Z")
Without the cap I believe 1" tubing will fit snug in the opening as well ---
**Author:** ![erockrph](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/erockrph/32/13330_2.png) [@erockrph](https://forum.homebrewersassociation.org/u/erockrph)\ **Post date:** [September 10, 2014, 7:27pm UTC](https://forum.homebrewersassociation.org/t/6-gallon-better-bottle-fermentation-capacity/17595/12 "2014-09-10T19:27:28Z")
> [@duboman](#): > > Without the cap I believe 1" tubing will fit snug in the opening as well For a regular carboy, yes, but not for a BB. They have an extra wide (1.75 in) opening, which is much larger than a standard glass carboy. ---
**Author:** ![duboman](https://sea1.discourse-cdn.com/brewersassociation/user_avatar/forum.homebrewersassociation.org/duboman/32/5890_2.png) [@duboman](https://forum.homebrewersassociation.org/u/duboman)\ **Post date:** [September 10, 2014, 8:28pm UTC](https://forum.homebrewersassociation.org/t/6-gallon-better-bottle-fermentation-capacity/17595/13 "2014-09-10T20:28:22Z")
> [@erockrph](#): > > > [@duboman](#): > > > > Without the cap I believe 1" tubing will fit snug in the opening as well > > For a regular carboy, yes, but not for a BB. They have an extra wide (1.75 in) opening, which is much larger than a standard glass carboy. Thanks, it’s been awhile since I used a carboy:)