On Jan 19, I brewed what will end up being a 5 gal. batch of Nut Brown Ale. I had decent mash efficiency and ended up at 1.046 @ 68 deg. after the boil and subsequent cool. I then split the total of six(6) gal of wort evenly into two sanitized corneys. The evening before I made a yeast starter with 2C water to 1/2C light DME and two packets of Safale S-04 dry Ale Yeast and left it on the stir plate with sanitized foil over the top of the flask. I pitched this yeast split evenly between the two corneys and sealed and shook/stirred the kegs. Then I installed my air locks which are nothing more than air in connectors with a copper tube for structure running through a vinyl tube to a regular air lock. I have used this method once before quite successfully. I stored these in the den with a brew belt around the middle of both kegs. After only a few hours, I started to see reasonable activity in the air locks. Just two days later we were hit with a cold snap that dropped the house temp to between 60 and 64. At that point, the activity stopped completely. It is now the 31st of Jan. The cold snap has been over for a couple days now but the former activity has not resumed.

Should I be concerned that the fermentation is completely stalled? Should I do something to restart it and if so, what?

  • How did you brew a 5 gal batch and end up with 6 gallons of wort?
    – paul
    Jan 31, 2014 at 20:15
  • It will end up at 5 gal +/- once I move it from the two fermenters to the serving keg. Jan 31, 2014 at 20:34
  • Just took a sample and SG comes in at a whopping 1.022 and I was looking for 1.008. Seems to me it's not done yet but I don't know where to go next. Feb 11, 2014 at 16:35
  • Beers sometimes don't attenuate all the way for a variety of reasons. It's a common problem. But 51% is very low. I would wait a few more days though, 14 days minimum on an ale like this. You may be able to get it to go a little further warming it up, swirling it around or adding more yeast. Try to control temp. The cause may mean that you can't go any further (bad pH for yeast, a lot of unfermentables in there, etc). homebrew.stackexchange.com/search?q=stuck+fermentation homebrew.stackexchange.com/questions/tagged/attenuation howtobrew.com/section4/chapter21-1.html
    – paul
    Feb 11, 2014 at 18:53

2 Answers 2


You need to know what the gravity is to know if it has stalled. Airlock activity will not tell you this. This is documented in several other questions. For example:

No bubbles in the airlock - should I still bottle the brew?

First Time Airlock Won't Start

Also for future reference, one standard 11.5g packet of S-04 easily has enough cells to ferment 5 gal, or even 6 gal at that 1.046, without a starter. A good place to check to see if you need to make a starter is the Mr. Malty pitching rate calculator. Not having to make a starter is a big advantage of dry yeast.

Also, S-04 is designed to be pitched directly into wort, so you don't really even need to rehydrate it (although some homebrewers advocate rehydration).

60-64 degrees probably would not knock out S-04 though. So it's probably finished, but the only way to know is with a hydrometer reading.

There are other questions about rousing yeast (increase temp, rock the fermentor), or adding more yeast (almost definitely not going work here, you should have had plenty to begin with with 2 packets of dry yeast).

For more information I would search this site, there are a bunch of questions and answers related to this: https://homebrew.stackexchange.com/search?q=stuck+fermentation


In my experience, S04 is really slow at lower temps. I had an oatmeal stout that took about 4 weeks to reach the anticipated FG at about 62F ambient temps. Time is your friend. As Paul points out, the airlock is not much of an indicator, as well, when fermentation slows you may not be able to see any activity, but it will still be working. Check the gravity every week or so until it reaches anticipated FG and you should be fine.

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