Stuck Fermentation or Just A High Final Gravity

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rtrevino

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First off I'm sorry but I don't have the recipe with me for this batch but it is a Dos Equis clone with an OG of 1.046 and I've checked it several times this week but the gravity has been stuck at 1.020 and we are going on about 3 weeks now. Im not sure about attenuation values and such but from what I've read this value is like 24%. Should I just try stirring up the yeast cake, should I repitch, or should I just call it quits and keg it?
 

Revvy

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If it is extract I'd say it is the 1.020 curse, and it is done. It's almost expected these days that extract batches often finish at 1.020 (or 1.030 on occasion) and nothing will bring them lower. Back in my extract days I bottled many a batch that finished that high, the beers were fine. I've often wondered if it doesn't have something to do with the production of some nonfermentable sugars in the wort carmelization during the boil.

A recipe would help though....
 

KAMMEE

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I agree with Revvy, I've had a few finish higher than I liked but actually turned out surprised at the result in that they're better than originally anticipated.
 

Calder

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If it is at 1.020, it is not finished. You didn't provide too many details. Most common cause of stuck fermentation is temperature. Get it up to 70 F and see what happens.

If it is extract I'd say it is the 1.020 curse, and it is done. It's almost expected these days that extract batches often finish at 1.020 (or 1.030 on occasion) and nothing will bring them lower. Back in my extract days I bottled many a batch that finished that high, the beers were fine. I've often wondered if it doesn't have something to do with the production of some nonfermentable sugars in the wort carmelization during the boil.
I totally disagree! I am getting tired of people blaming extract for high FGs. Agreed, you can get lower with mashing grains low, but that's only if you deliberately mash low. Agreed, there are some extracts that have a lot of unfermentables (example; Laagerlander). But for the most part they are just as fermentable as an average (low to mid 150s) mash.

I partial mash, about 5 lbs grain per brew, so the majority of my fermentables are from extract. Occasionally to I use extract exclusively. I have never had a stuck fermentation, and usually get higher than the advertised max attenuation advertised by the yeast.

I'm on brew number 180, highest finish I've ever had is 1.016, and that was 75% attenuation ...... right in line with the yeast spec.
 

Revvy

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I totally disagree! I am getting tired of people blaming extract for high FGs.
You may be tired of hearing something, but that doesn't make it any less true. It's unfortunate but it does seem that a lot of extracts beers that new brewers come in here having issues with are stuck at 1.020, despite everything they try, swirlirng, raising the temps, even pitching more yeast....I didn't coin the term 1.020 curse afterall. It just seems to happen to a lot of folks. I had my share of extracts peter out at that number over the years. It's no big deal, it's just seems to be a fact of life for many brewers that their extract batches finish there. There's countless discussions about it on every beer forum. What is it they say, "1 is an anamoly, 2 is a coincidence, 3 is an epidemic...."

*shrug*

But that point is moot since this isn't an extract batch anyway is it?
 

soundsandsuds

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It will also vary with the brand of extract. Calder: what are you using?

Extracts with adjuncts will have unussually high fermentability.
 

Calder

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I almost exclusively use Briess; Light or Pilsner.

I think a lot of the problem with high FGs has nothing to do with the extract, but has more to do with 'New brewers', and poor practices; under-pitching, fermenting too hot/too cold, and general yeast health, inadequate aeration, and racking off too early and leaving the yeast in the primary.

Revvy; I think the common thread is 'New brewer', and not the extract. I think you or I could take any of these kits and produce a well attenuated beer from it. Probably the first thing we would do is replace the yeast (often times you don't know it's age, storage conditions, or even what yeast it is), and pitch a healthy starter, aerate well, and keep it at the right temperature.
 

Homebrewtastic

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Should I just try stirring up the yeast cake, should I repitch, or should I just call it quits and keg it?
Stirring up the yeast cake isn't really going to do anything to help fermentation. The yeast could have stopped for a few reasons. The most likely is that they ran out of food. If you're doing all grain, is it a possibility you missed your mash temps (thermometer could've been off)? If so that could be an easy culprit.

You might have pitched too much or too little yeast. You could've stressed the yeast out with temperature fluctuations... There's all sorts of things.

Pitching more yeast directly in won't necessarily help either. One possibility is to take some fresh yeast and make a starter. Once your starter is at high krausen add that to the fermenter. By doing this you're ensuring that your yeast are awake and healthy and giving your beer a fighting chance.
 

MuddyMo

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You probably have fermented all the fermentables you extracted then. Without seeing your recipe and you temps it's really hard to tell.

But remember there's no sin in a 1.020 beer. If it's finished it's finished.
Revvy, I have virtually the same problem, but I have all the info. So, allow me to highjack this thread, if I may.

8 lbs. Maris Otter info
.75 lbs. 2-Row Caramel Malt 40L info
.25 lbs. Belgian Special B info
.25 lbs. Chocolate Rye Malt info
.5 lbs. Cara-Pils® Malt info
Yeast : WYeast 1084 Irish Ale info 1L Yeast starter

BIAB method, Mash @ 152F for 60 min. Iodine test shows conversion, sparge @ 170F to get 5.5 gallons gravity @ 1.041

60 min boil, cool and rack to carboy, top up to 5 gal with 4 cups water, gravity at 1.044.

1L Yeast starter pitched into @ 75F wort (should have just pitched the slurry, I know). Placed in swamp cooler with chilled water with intent to lower to 62F, but it got down to 54 after 6 hours. I nixed the ice, the temp started rising an signs of fermentation began at 6 hours, with the krausen formed and vigorous fermentation starting about 30 hours later and lasted about 48 hours, temp never gets above 63F. As the krausen started dropping, the fermenation slowed but was steady for 2 more days. On the fourth day let temp rise to 64F and began to rouse the yeast daily.

refractometer reading 1.020 after 7 days with temp at 64F, another reading 24 hours later was unchanged, raise temp over two days to 68F, today's reading still 1.020; The sample does not taste overly sweet.

Its not that I can't live with a batch of 3.1% beer, but I would feel better if I could be reasonably sure there weren't any fermentable sugars remaining. It is hard to imagine I only got 53% attenuation considering how vigorous the fermentation was. But this is the first time I have tried to ferment by chilling the wort, so I'm not sure what to expect.
 
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