Stuck fermentation... Why?

Looking for any reasons, input, suggestions, condolences... My brown ale has been in the fermenters for 2 weeks now, and has only moved 20 gravity points... The recipe is:

Golden promise
Carabrown
Red wheat
C-120
Aromatic

Yeast is wyeast 1450, 1 liter starter for 10 gallons, split into two fermenters

Mashed at 155 for 60 minutes...

Both fermenters started up in <24 hours, krausen coming out of the blow off tube, I thought it was a healthy fermentation, but after 2 weeks its only moved 20 points. Started at a 1.061 now I'm at a 1.041.

I pulled one liter out of one fermenter and pitched a fresh jar of yeast to ensure it is ferment able wort and repitch, but I'm looking for any reasons why or other suggestions to save this beer...

Sounds like it could just have been underpitched. For 10gal at 1.061 you'd need a 4-5L starter with only one pack of yeast.

Double check the accuracy of your thermometer. Also, how much of each grain/malt did you use in the recipe?

A 1L starter, even if you used a stirplate, is way too little yeast for that batch size. You needed 431 billion yeast cells for that batch (total). Even if the yeast pack was young, and from the same month, you would have needed a 9.4L starter with intermittent shaking, or 6.2L starter on a stirplate. Going with a two step starter schedule would have knocked those down into lower numbers.

How did you aerate/oxygenate the wort?? Did you add any nutrients to the wort during the boil?

Golddiggie said:

Double check the accuracy of your thermometer. Also, how much of each grain/malt did you use in the recipe?

A 1L starter, even if you used a stirplate, is way too little yeast for that batch size. You needed 431 billion yeast cells for that batch (total). Even if the yeast pack was young, and from the same month, you would have needed a 9.4L starter with intermittent shaking, or 6.2L starter on a stirplate. Going with a two step starter schedule would have knocked those down into lower numbers.

How did you aerate/oxygenate the wort?? Did you add any nutrients to the wort during the boil?

Click to expand...

I'll take a look and post up the exact recipe.

My initial thought was under pitched, but would it behave like this of that was the case? It started up quickly and krausened high... Then it just putzed out.

With it kicking off that fast, into full active fermentation, the yeast wasn't the issue (IMO). More likely your thermometer is seriously off and you mashed much higher than you thought. Or your reading the hydrometer incorrectly. Are you using a hydrometer or refractometer? If you're using a refractometer, then you cannot use the raw reading, but need to run it through the software/formula to compensate for the presence of alcohol.

Golddiggie said:

With it kicking off that fast, into full active fermentation, the yeast wasn't the issue (IMO). More likely your thermometer is seriously off and you mashed much higher than you thought. Or your reading the hydrometer incorrectly. Are you using a hydrometer or refractometer? If you're using a refractometer, then you cannot use the raw reading, but need to run it through the software/formula to compensate for the presence of alcohol.

Click to expand...

That was my thought too... The thermometer isn't that far off though, I have used it again since with better results. It is possible that I read it wrong though...

I'm using a hydrometer to read the gravity, and have tested it in plain water to be accurate, and measured other batches with it with better accuracy...

The new liter of wort that I pulled off and re-pitched yeast into seems to be starting. I pitched the yeast late sat night, have been shaking intermittently, it hasn't krausend up yet but the yeast are staying well in suspension and it is releasing a decent bit of gas every time I shake it.

With this new starter, do you guys suggest letting it ferment fully and flocking out before pitching it back into the fermenter? Or pitching it at high krausen?

Also, the detailed recipe is as follows:


16# golden promise
3# aromatic
3# carabrown
2# red wheat
8oz crystal 120
8oz coffee wheat malt

Pitch at high krausen. That's a lot of aromatic/cara, FWIW. Test hydrometer in 60* water (your wort samples should be 60* as well). Check thermometer in well-stirred ice-water and in rapidly boiling water.

tre9er said:

Pitch at high krausen. That's a lot of aromatic/cara, FWIW. .

Click to expand...

You would still expect more than a 20 point drop from it though...

What about temp control? How do you do it and what were the actual beer temps during fermentation? If you cooled at any point, it could have encouraged the yeast to fall out. I always recommend a slight warming after initial fermentation has slowed down. That encourages yeast to stay in suspension. A gentle swirl can help, too.

tre9er said:

What about temp control? How do you do it and what were the actual beer temps during fermentation? If you cooled at any point, it could have encouraged the yeast to fall out. I always recommend a slight warming after initial fermentation has slowed down. That encourages yeast to stay in suspension. A gentle swirl can help, too.

Click to expand...

I do that simply by keeping the house cold... Fermentation temps stayed at about 67-69 degrees for the entire time, so inside the fermenter could have been somewhere near 72° at the peak of yeast movement. I swirled one fermenter and a lot of gas was released, but I haven't noticed anymore movement out of it. Fwiw, there was very little yeast slurry at the bottom of that fermenter when I did that, so the cells obviously didn't multiply very much.

I am hoping that this new starter hits high krausen in the next few days, so it will prove that the wort is indeed fermentable... If it never hits high krausen, I will cold crash and take a gravity reading of this forced fermentation to see if it moved at all and try to determine whether or not its salvageable.

Also, taste it. Is it cloyingly sweet still? Gravity obviously matters, but I also wonder how it tastes.

I suspect the following:
1. Way underpitched and a lot of really stressed out yeast that just plain quit
2. A high amount of less fermentable malt in that grain bill
3. A thermometer that is off- a 2-3 degree difference in the wrong direction can create a very different wort than expected

Just because you are getting airlock activity when you move the primary does not mean any further fermentation is actually occurring, just that gasses are escaping and it could just be off gassing. If there is any question as to what the beer is doing then take another reading.

If you elect to re-pitch then definitely do it at high krausen so you don't add any more stressed out yeast to the batch Raise the temp a bit and keep the yeast in suspension. Give it a week and take a reading.

tre9er said:

Also, taste it. Is it cloyingly sweet still? Gravity obviously matters, but I also wonder how it tastes.

Click to expand...

Yeah, it's definitely sweet... It has a GREAT flavor to it, but very sweet still...

If it can get anywhere closer to 1.015-1.020 I think it would be great and I would consider that a full fermentation for it given the ingredients and mash temp. Bt it's got a little ways to go before it gets there...

Something to think about... You only have 64% base malt in that recipe. With all the trouble you're having getting it to ferment to where you want it, I would seriously think about not using so much other malts moving forward.

I do my best to have at least 80% base malt in my recipes. If I go lower, there's a damned good reason for it, and it's not all that far below that level. I prefer to have more like 85-90% base malt. Even my DARK ales have 80% base malt (or better)...

Golddiggie said:

Something to think about... You only have 64% base malt in that recipe. With all the trouble you're having getting it to ferment to where you want it, I would seriously think about not using so much other malts moving forward.

I do my best to have at least 80% base malt in my recipes. If I go lower, there's a damned good reason for it, and it's not all that far below that level. I prefer to have more like 85-90% base malt. Even my DARK ales have 80% base malt (or better)...

Click to expand...

True, but those should have contributed some fermentable sugars to the base as well...

But definitely a point to note.

tre9er said:

Pitch at high krausen. That's a lot of aromatic/cara, FWIW. .

Click to expand...

It's alot of cara but aromatic malt is fermentable, so I'm not sure what's going on it. (You can actually use 100% aromatic malt as a base malt, although I wouldn't recommend it for best flavor- it does have enough DP to convert itself. It's just a "higher" Munich malt).

I think there are two main causes of this stuck/slow fermentation:

1. Underpitching. It was a huge underpitch, and that is a big issue.
2. Too high mash temp. If it was 155, it might not be too high. But if the thermometer was even 1.5 degrees off, then it WAS too high. That could be a contributing cause.

I feel pretty confident in the thermometer accuracy, I used it a few weeks prior at 153° for a stout that finished at 1.1014, and again for a smoked pale ale at 150° that has been VERY active...

I'm not ruling out human error though.

HollisBT said:

I feel pretty confident in the thermometer accuracy, I used it a few weeks prior at 153° for a stout that finished at 1.1014, and again for a smoked pale ale at 150° that has been VERY active...

I'm not ruling out human error though.

Click to expand...

Then I say it's the recipe used is the culprit.

Thermometers become less accurate as temperatures go up, so it may read dead on at room temperature but be way off at mash temps. My floating thermometer runs 4-5 degrees higher at mash temperatures than it should. If yours is way off that 155F mash could have been 160 or higher. Nevertheless, even a 160F beer should ferment out more than 20 points.

Between the golden promise and aromatic you definitely have enough diastatic power to convert those starches, so the recipe is fine.

Your most likely culprit is underpitching and underaerating. Shake the **** out of your fermenters and add some nutrient.

So my starter is yet to hit any level of krausen, yeast was pitched into it on Sunday morning... The yeast is staying in suspension nicely, and every time I swirl it I am getting anime release of co2, so it seems like there has been activity in it...

It's starting to concern me though that it isn't getting highly active. Starting to wonder if I should let it ferment out completely and then cold crash it and take a gravity reading before pitching it to one of the full fermenters, or just wait and pitch it and see what happens. Any suggestions/input?

a stir-plate would be ideal here. If the gravity of the starter is lower than your beer (since you took beer to make the starter, right?) then there has been replication and you could pitch.

If you made the starer on Sunday then it's done. Most starters ferment out in 18-24 hours regardless of how you stir or shake and it is typical to not see much if any activity. If you are really concerned then take a gravity reading but IMO you can go ahead and crash it, decant it and pitch!

Thanks guys .

I'll pitch it in the morning, not going to bother crashing and decanting, since I made the starter from the original beer. I'll just pitch and cross my fingers.

tre9er said:

a stir-plate would be ideal here. If the gravity of the starter is lower than your beer (since you took beer to make the starter, right?) then there has been replication and you could pitch.

Click to expand...

IMO/IME, a stirplate is ALWAYS a great idea when it comes to making starters.

Golddiggie said:

IMO/IME, a stirplate is ALWAYS a great idea when it comes to making starters.

Click to expand...

i hear ya. now that i have one my previous starters seem like i hardly did anything to the yeast. this time i had mad foam/krausen, including the typical leftover ring you get with a "real" beer ferment. Was triple easy, too. Got the thermaltake fan with speed control and USB power cord, stir-bar, and a few magnets and BAM!

Making the first starter step tonight for a batch I'm brewing on Saturday. All of .7L is needed for the first step. Second step will be 1L in size (probably made Thursday evening). I'll get the yeast cell count needed with the two small starters that would have taken a larger starter (at least 3L, so about double). IMO, using less DME to get the cell count is a win in my book. I can easily plan to make the starters far enough ahead. :rockin:

Alright, next question... When I re-pitch should I aerate again? Or just give it some swirls to mix the yeast in...

I'm guessing no go on the aeration since there is some alcohol present.

I wouldn't aerate again.

I pitched this morning, fingers crossed and hoping for the best...

One week later, and we are at 1.028...


I'm not giving it too much longer before I give up on it...

54% AA, meanwhile a pale ale mashed at 150 and fermented with a single smack pack gets 84% and ends up at 1.008...


Saccharomyces, quit being a-holes!,

HollisBT said:

54% AA, meanwhile a pale ale mashed at 150 and fermented with a single smack pack gets 84% and ends up at 1.008...


Saccharomyces, quit being a-holes!,

Click to expand...

I think that Denny just doesn't like you, or the wort you pitched him into...

If you really want it lower, I'm telling you, add half a teaspoon of amylase enzyme (cheap, from LHBS). It will go lower.

Toss some 3711 in that thing! That yeast eats everything!

Golddiggie said:

I think that Denny just doesn't like you, or the wort you pitched him into...

Click to expand...

I'm thinking not... He did well before. I'm guessing too many unfermenrables in the recipe.

tre9er said:

If you really want it lower, I'm telling you, add half a teaspoon of amylase enzyme (cheap, from LHBS). It will go lower.

Click to expand...

This might be a last ditch effort. If that doesn't do it, I'm giving up and dumping it.

HollisBT said:

This might be a last ditch effort. If that doesn't do it, I'm giving up and dumping it.

Click to expand...

Don't dump it... Worst case, keep it and mix it with something else later. You could, also, try pitching a vial of WLP099 in there.

Golddiggie said:

Don't dump it... Worst case, keep it and mix it with something else later. You could, also, try pitching a vial of WLP099 in there.

Click to expand...

Ehh, maybe... We will see...

I'm still confused by it to be honest. Between this beer, the aforementioned pale ale that over fermented, and a stout that actually used FEWER fermentables in the recipe than the brown yet finished at 1.016 (mashed just 2° lower...), I just don't understand...

HollisBT said:

One week later, and we are at 1.028...

I'm not giving it too much longer before I give up on it...

Click to expand...

Transfer it to a secondary. Make a new starter of your choice. wlp001 or whatever. Aerate starter. It can be a quart starter. Stir it as often as you can if no stirplate. Once the starter is at peak activity, pitch it.

You cannot just toss inactive yeast in. They will fall out. Raise temp 2-3 degrees.

Doing these things will probably fix it.