Ss Brewtech’s Biggest Baddest Holiday Giveaway Ever!

Home Brew Forums > Home Brewing Beer > Beginners Beer Brewing Forum > Outgassing vs. Fermentation
Thread Tools
Old 04-08-2009, 08:03 PM   #1
Feedback Score: 0 reviews
Join Date: Feb 2009
Location: Tucson, AZ
Posts: 2,551
Liked 30 Times on 22 Posts
Likes Given: 16

Default Outgassing vs. Fermentation

I have a primary that has had airlock activity for over 3 weeks. What is the difference between outgassing and fermentation, and how long can outgassing occur after fermentation is finished?

follow me @ Broken Glass Brewery

Okham's Razor - simplest explanation is usually the correct one.

My DIY Kegerator - My DIY Fermentation Chamber - My DIY Portable Pump Box
Schnitzengiggle is offline
Reply With Quote
Old 04-08-2009, 08:06 PM   #2
Feedback Score: 0 reviews
bradsul's Avatar
Join Date: Sep 2006
Location: Ontario, Canada
Posts: 4,894
Liked 26 Times on 23 Posts
Likes Given: 4


Only your hydrometer knows the difference. Once the reading is the same for 3 days in a row it's finished fermentation and just outgassing. At three weeks I'd guess fermentation is most likely finished.
Canadian Brewers Unite!

Projects: Sylvania Kegerator Conversion, Tower Cooling, Grain Milling Station
bradsul is offline
Reply With Quote
Old 04-08-2009, 09:16 PM   #3
Feedback Score: 0 reviews
Join Date: Nov 2007
Posts: 4,457
Liked 115 Times on 103 Posts
Likes Given: 32


If you have a carboy or Better Bottle, it's easy to tell - shine a flashlight in there and see where the bubbles originate. If they all come from the yeast bed, you've got fermentation (or, at least, organic activity - anaerobic breakdown of organic matter can also release gases unrelated to fermentation). If the bubbles originate from the walls of the carboy well above the yeast bed, you've got outgassing.

As long as your expected final gravity has been reached and has remained stable for a week or so, you can convince those last, persistent yeast to quit by cold crashing.
ArcaneXor is offline
Reply With Quote

Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
Fermentation cooler vs refrigerator vs son of fermentation Belmont General Techniques 18 08-15-2015 05:54 PM
Wine fermentation vs beer fermentation Tophe Wine Making Forum 4 11-19-2010 07:38 PM
Which is better? A fast, very active fermentation, or a slow steady fermentation? cerberus9 Beginners Beer Brewing Forum 6 09-24-2009 04:56 PM
Lager outgassing HotbreakHotel Fermentation & Yeast 4 09-04-2009 10:45 AM
Imperial stout still outgassing or infected? gyoder Fermentation & Yeast 1 08-11-2009 01:32 AM

Forum Jump

Newest Threads