Consistent stuck fermentations

[crocks86]

Hello,

This is my first post on here, I've come here for advise a good few times but I haven't found anything exactly like my current problem. I know theres a thousand stuck fermentation threads here but I seem to be having a consistent problem with fermentation (4 batches now).

Basically they all start off solid, quick bubbling within 12 hours and good looking krausen they seem to be going fine for a few days and then start to drop out, everything looks fine but after a week or 2 when I check the gravity they haven't dropped near as far as they should have. Example: my pale ale started at 1.050 or so, should have had a FG of 1.013 but after about 4 weeks is at 1.035.

This is 4 batches in a row that do the same kind of thing, different types of beer and yeast (I 've used Irish ale, American ale and London ESB all from wyeast) and even tried adding extra dry yeast to the pale ale and it hardly changed the gravity. I've tried them in different areas of the house ranging from about 16-22C and nothing seems to help. The yeast appeared healthy, packages swelled properly, and one I made a starter that was overflowing by the time I used it.

I'm using very small fermenters (1 gal) I don't know if that could have an effect on them, I was told by my LHBS that it shouldn't, and they didn't have any idea what was happening either.

I would blame it on being a total newb but my first batch (fermented in the same area (same temps) that most of the stalled ones were in) came out perfect. Also these are all extract batches so I can't blame it on bad mash temps.

any suggestions would be great, Thanks.

 

[NordeastBrewer77]

First off, welcome to the forum!! Second, a bit more info, like recipes and process, would be useful. Maybe we can figure out what's causing your beers to stall.

 

[william_shakes_beer]

If you have a wort with a large amount of infermentable sugars they will finish out high. Aside from not having the alcohol you're looking for, how do they taste?

 

[PistolsAtDawn]

Yes, more info please. Are you doing extract kits or all-grain?

 

[hector]

Yes, more info please. Are you doing extract kits or all-grain?

"crocks86" already said that they were all Extract Batches .

Hector

 

[kapbrew13]

If you have a wort with a large amount of infermentable sugars they will finish out high. Aside from not having the alcohol you're looking for, how do they taste?

Yes, how does it taste? Is it sweet?

 

[hector]

This is my first post on here, I've come here for advise a good few times but I haven't found anything exactly like my current problem. I know theres a thousand stuck fermentation threads here but I seem to be having a consistent problem with fermentation (4 batches now)....

I've had exactly the same problem with my previous Extract Batches .

You didn't mention the most important thing , BOILING .

Do you add all of the Extract at the beginning of the boil ?!

Hector

 

[crocks86]

I'm using muntons light dry extract with regular hop additions (not any prehopped extract or anything). I won't bother writing out all the recipes yet but the pale ale for example was one from the ibrewmaster app 'Petes wicked clone':

0.85lbs light extract
0.04 lbs Chocolate
0.1 lbs Crystal 80

0.05 Oz Chinook (60 min)
0.08 Cascade(60 min)
0.08 Cascade (10 min)

American ale yeast

Final volume was about 0.8 gal to give room in the 1 gal fermenter, start at about 1.5.

The amounts look ridiculous since its such a small recipe but I don't think that should affect anything, at least I was told it shouldn't.
The others were around the same volume with the extract making up at least 80% for all but one, but that one actually didn't have as big a difference between the predicted FG and actual FG.

They taste alright actually, to be honest the bitterness is coming through more than the sweetness, I assume since the hop amounts are so small its bound to be inaccurate on the scale but thats not my main problem here.

I assume the recipe is okay, I didn't change much from the actual one besides maybe hop types.

 

[hector]

I'm using muntons light dry extract with regular hop additions (not any prehopped extract or anything). I won't bother writing out all the recipes...

I repeat my question :

How did you add your Extract ?

All at the beginning ?!

Hector

 

[crocks86]

I missed that last post, I've been adding it all at once at the beginning. I've heard it may be better to split but I didn't think that had an effect on fermentation I thought it was just for hop utilization.

 

[scoundrel]

The amount of yeast maybe to blame. Alcohol is toxic to yeast; kinda like swimming in your own waste, so adding yeast back near the end of the process is no guarantee that the yeast will wake back up.

I've used this analogy before but think of it like this. If you and a friend won a sweepstakes to eat 70% of a buffet. You can bring as many additional people as you need to reach the goal.

Now if you and your friend tried to do it alone, you'd fall on the floor after a few plates of food, but if you brought 100 friends, you'd easily reach your 70% goal.

1.035 sounds really high and will be sweet. Next time pitch double the amount of yeast and see what happens.

 

[hector]

I missed that last post, I've been adding it all at once at the beginning. I've heard it may be better to split but I didn't think that had an effect on fermentation I thought it was just for hop utilization.

That's why I insisted on my question .

Boiling all of the Extract for 60 minutes leads to lots of unfermentables due to caramelizing the simple sugars .

Therefore , it's recommended to add a small amount of it , for example 30% at the beginning of the boil and the rest after 45 minutes .

Some Homebrewers add the remaining even at Flame-out to prevent it from being caramelized .

Hector

 

[crocks86]

Well that makes sense, I'll try that next time. Thanks Hector

but why doesn't that affect all grain batches? I'm hoping to move up to all grain within a few weeks when I get a new house and more room to work with.

 

[TimTrone]

Well that makes sense, I'll try that next time. Thanks Hector

but why doesn't that affect all grain batches? I'm hoping to move up to all grain within a few weeks when I get a new house and more room to work with.

There's many reasons. The main being that with AG you have control over the fermentability over the wort with the mash temp. Plus, you do a full boil with AG.

With extract, you can do late extract additions, full boils, or even add some simple sugar to help with fermentability of your wort.

 

[crocks86]

Thanks guys. Should help for next time but I guess theres nothing I can do but toss or drink very low alcohol beer for now

 

[bmbigda]

I'm wondering if overpitching may be causing this. It seems highly unlikely, and I admittedly have nothing to support this theory other than that the only thing you are different from most people is very small batches, with the same yeast cell counts. Perhaps someone who's read Jamil's book can chime in.

 

[Yooper]

Thanks guys. Should help for next time but I guess theres nothing I can do but toss or drink very low alcohol beer for now

The extract didn't caramelize. But adding 1/2 the extract at the end of the boil instead of all at once is good practice, as it will give the flavor a less "cooked extract" taste. That's not why it stalled, though.

I would consider lack of oxygen and not enough healthy yeast as the likely cause of a stuck fermentation. But with a starter, it should have viable yeast. How much yeast did you pitch in the 1 gallon batches?

How are you measuring the FG? I assume a hydrometer? One thing to make sure you get accurate FG readings is to spin the hydrometer a bit and make sure it's not being held up by any bubbles in it and not touching the side.

Does the beer actually taste sweet? At 1.035, it should taste very sweet.

 

[scoundrel]

The extract didn't caramelize. But adding 1/2 the extract at the end of the boil instead of all at once is good practice, as it will give the flavor a less "cooked extract" taste. That's not why it stalled, though.

I would consider lack of oxygen and not enough healthy yeast as the likely cause of a stuck fermentation. But with a starter, it should have viable yeast. How much yeast did you pitch in the 1 gallon batches?

How are you measuring the FG? I assume a hydrometer? One thing to make sure you get accurate FG readings is to spin the hydrometer a bit and make sure it's not being held up by any bubbles in it and not touching the side.

Does the beer actually taste sweet? At 1.035, it should taste very sweet.

Ya, I don't buy boiling extract for 60 minutes is the reason. It's not like an AG brewer mashing at higher temps to increase dextrins. The supplier who originally mashed your extract determined fermentability. Like Yooper said you'll get less of a cooked taste and also lighter beer by adding extract later in the boil.

I agree that lack of oxygen and not enough healthy yeast is most likely the culprit.

 

[hector]

I would consider lack of oxygen and not enough healthy yeast as the likely cause of a stuck fermentation.

I've had the same problem by my previous batches , although by all of them I had aerated the wort well after the boil and used a healthy yeast strain !

Hector

 

[SwampassJ]

Are you using a hydrometer or a refractometer?

 

[hercher]

At the risk of asking an obvious question, are you certain your hydrometer is accurate? Test it in some water @ 65 degrees and be sure it shows a gravity of 1.000. You mentioned that beer tastes OK, so that's why I ask.

 

[crocks86]

I'm using a hydrometer and making sure its not stuck to the side or affected by bubbles, also tested pure water to make sure it was reading properly, I'm waiting on a refractometer in the mail.

I've been pitching full smack packs, I was going to split them up but the guys and the brew store said it wasn't worth it and too much yeast shouldn't be a problem, then I could just harvest the yeast after fermentation.

And it doesn't taste too sweet really, not near as sweet as I would expect.

I also give the fermenter a good shake/swirl for a couple of minutes once the yeast is added.

 

[PistolsAtDawn]

I agree that a lack of oxygen in the wort before pitching is a likely culprit.

Shaking a carboy or other fermenter really, really well can provide a decent amount of dissolved oxygen for the yeast, but it's likely not really enough to provide the healthiest fermentation.

Commercial breweries actually inject pure O2 into their wort, and we're dealing with regular ol' air. All the same, you might try to aerate a lot more.

I hope you get it nailed down.

 

[ChillWill]

Commercial breweries actually inject pure O2 into their wort, and we're dealing with regular ol' air. All the same, you might try to aerate a lot more.

We actually use air through a sterile filter and can get over 8ppm which is ample for pitching 5 million cells /ml

 

[crocks86]

I thought the problem may have been aeration, but my first batch was aerated less if anything compared to the stalled ones and it came out fine. Maybe it was a combination of lack of air and older yeast compared to the first one. It kills me that I have to wait till May to do another batch and find out if my problem is solved.

 

[PistolsAtDawn]

There's a great summary of some recent thinking in regards to aeration in this thread:

https://www.homebrewtalk.com/f163/i-completely-underestimated-role-oxygen-235663/index5.html

It's definitely worth a read from the beginning, but pages 5 and 6 have what I think is the most persuasive information.

 

[crocks86]

cool, thanks!