Stuck or Slow Fermentation

Question

Stuck or Slow Fermentation

briansimmons

2010年3月5日 12:19

So I have my first possible stuck fermentation. First, my recipe:

http://hopville.com/recipe/166971/extra-special-strong-bitter-english-pale-ale-recipes/shoals-pale-ale-clone

I pitched with two Wyeast packs of London ESB Ale as recommended by the LBS due to starting gravity. When I finished brewing, I realized that a hydrometer I had bought turned out to be a floating thermometer, so I could not take a first reading. I let it go as normal. Activity was normal for the first few days but never got really bubbling. I chalked this up as my first primary in a bucket vs. a carboy.

After 4 days, bubbling activity really slowed down. I considered adding more fermentables, but I had at least 5lbs of liquid malt extract plus my grains. I also find it hard to imagine that with two smack packs, the yeast didn't take off (I also aerated my wort before pitching and let the smack packs inflate for a few hours).

Today is day 8 and I picked up a hydrometer last night and took a reading. It is currently sitting at a gravity reading of 1.015, estimated at 2% ABV. My target is 5.5% ABV. Do I possibly have a stuck fermentation? What should I do, besides wait it out a few more days and take another reading?

EDIT: In my haste, I failed to check the temperature of my sample. My hydrometer is accurate at 60 degrees F. I will take a second sample and repost the new results.

UPDATE: 2nd reading at 60 was very close to the original. Maybe 1.018 for the gravity. I guess I can't figure out my ABV without an original reading but I can take another reading in a few days and see if it's still fermenting?

Topic smack-pack original-gravity fermentation homebrew troubleshooting

Category Mac

brewchez · Accepted Answer · 2010年2月25日 12:58

My anser may be a bit late, but the best way to handle a stuck ferment is to up the temp and rouse the yeast.

First step would be to get the fermentor someplace warmer and try and get the beer to 72Fish. Next step would be bear hug the fermentor and gently swirl it until some of the yeast starts to get lifted off the bottom. But you have to get it warmed up first, other wise the yeast will just a fall back to the bottom.

Problem with the swirl is that you need to see what's happening (so a bucket makes it tough) and limited head space makes it hard to swirl. Another option is to open the fermentor if its a bucket and go in with a long spoon or racking cane and stir up the cake a bit. There will be a little bit of oxygen introduction but it shouldn't be to bad, because of the layer of CO2 on top of the beer already if some fermentation already occured. Lastly, if the yeast do get going again, they'll suck up some of the O2 that was introduced during stirring.

I like this method prior to pitching more yeast or adding anything.

Adding more fermentables may bring back some activity as the yeast consume the fresh sugars, but there's no reason to believe they'll keep going and then get you below where you were when it got stuck. If anything you'll end up with a higher than before stuck gravity.

JackSmith · Accepted Answer · 2010年2月21日 17:58

How did you come up with 2% ABV? If you followed the recipe you posted exactly and you're currently at 1.015, then you're definitely done. That recipe says you should reach 1.019. With a starting gravity of 1.061 and and final gravity of 1.019, you'd be at 5.6% ABV. Assuming you started out at 1.060 and you hit 1.015, you're ABV is 5.81%. Not only are you not stuck, but you got a better-than-expected fermentation.

Stuck or Slow Fermentation

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