Badly stuck fermentations -- advice needed.

[rhamilton]

So I kegged three batches this weekend and everything looked like normal. Right before sealing the kegs I remembered to take FG measurements and to my surprise two of the batches were badly stuck; the 1.060/1.020 AG Brown Ale was sitting @ 1.036 and the 1.046/1.012 AG Pale Ale was sitting at 1.040 :-/

I can't remember exactly what happened but I believe I came home to the pale ale about to blowout so I threw it into the bathtub under cold water to slow the fermentation and for some reason I put the brown ale in there too. I did not measure water temps but it was likely in the high 50's to low 60's and there they sat for 24 hours. I took them out and put them back into the closet and three weeks later here I am.

They are sitting in corny kegs at the moment. Three days ago I agitated the hell out of them and repitched with Nottingham. I checked this morning and there is no sign of life. I'll recheck the gravity again when I get home to verify but I'm confident they are still stuck. I also don't have a yeast cake to rack them onto. My next yeast cake will probably be available Friday and the two batches will be hitting the 30-day mark today. I sampled both and they don't taste off yet but they are getting old and the Pale Ale is only @ 0.8% ABV currently.

So what should I do?

 

[Kaz]

I say you have one of 2 problems...either you mashed warmer than you thought and there are more long chain dextrines in there that the yeast can't eat, or your measurement device is off. You say they don't taste 'off', do they taste too sweet? If they are stuck that high, I would think they would taste pretty sweet. Cooling down the carboys would've slowed the yeast, but not killed it. When you warmed them back up, the yeast would've kicked back into gear. I don't think adding more yeast is going to fix the problem. Double check your hydrometer and/or measuring device and the temperature you are using at to make sure your numbers are accurate and if they are, then I think you are truly 'stuck' for good.

 

[ChaosStout]

Add some Amylese Enzyme

 

[rhamilton]

Thanks for the advice. The Pale was all-grain but the Brown was actually a mini-mash kit. I expect I overshot temps on the pale ale and the cold tub water made things worse by making the yeast go dormant in both. I added 2 tsp of amylese enzyme to both batches last night and I'll be shaking twice a day until fermentation starts up again -- which hopefully should be tonight. I also added 1/2 tsp Wyeast nutrients to both for good measure. Hopefully it won't be horribly dry but we'll see. I'll post updates as they come.

 

[Yooper]

Thanks for the advice. The Pale was all-grain but the Brown was actually a mini-mash kit. I expect I overshot temps on the pale ale and the cold tub water made things worse by making the yeast go dormant in both. I added 2 tsp of amylese enzyme to both batches last night and I'll be shaking twice a day until fermentation starts up again -- which hopefully should be tonight. I also added 1/2 tsp Wyeast nutrients to both for good measure. Hopefully it won't be horribly dry but we'll see. I'll post updates as they come.

Did you double check your hydrometer with distilled water, to make sure it's accurate? That would be the first thing I'd do, before adding amylase. The mini-mash kit just shouldn't/couldn't be stuck.

 

[rhamilton]

Did you double check your hydrometer with distilled water, to make sure it's accurate? That would be the first thing I'd do, before adding amylase. The mini-mash kit just shouldn't/couldn't be stuck.

I use a refractometer -- first thing I did was re-calibrate and test again. The 3rd batch I kegged was right on the money too so that eliminated the possibility of bad measurement. I talked to the guys at my LHBS and they agreed the shock of going from 75°F air to a 50°F tub of water was enough to put the yeasts into dormancy. What is strange is 3 weeks back at 75°F didn't wake them up.

And for reference, the yeast strains are WLP001 (Cali Ale) and WLP002 (English Ale)

 

[bk0]

Are you correcting the refractometer readings?

 

[cshamilton]

Are you correcting the refractometer readings?

This. Maybe you know this already, but just in case: Alcohol throws off refractometer readings - you can do a "correction" which gives an estimate. There is probably a post every week with someone thinking they've got a stuck beer and they are using a refractometer.

Check with a hyrdometer if you have one.

To get a good estimate you can try this online calculator: http://onebeer.net/refractometer.shtml

 

[rhamilton]

This. Maybe you know this already, but just in case: Alcohol throws off refractometer readings - you can do a "correction" which gives an estimate. There is probably a post every week with someone thinking they've got a stuck beer and they are using a refractometer.

Check with a hyrdometer if you have one.

To get a good estimate you can try this online calculator: http://onebeer.net/refractometer.shtml

Doh! Never even knew I had to do an alcohol correction. The instructions with the refractometer didn't even mention that and it is specifically a brewing model.

Even with that correction calculator, the brown is 1.1% ABV short of target and the Pale is 4% off.

 

[Birdskull]

And if you use a hydrometer, you'll need to correct that reading aswell.

 

[cshamilton]

Doh! Never even knew I had to do an alcohol correction. The instructions with the refractometer didn't even mention that and it is specifically a brewing model.

Even with that correction calculator, the brown is 1.1% ABV short of target and the Pale is 4% off.

Looking at the numbers you posted earlier, I think the brown is OK - the Pale was off for sure. Based on your readings I'd estimate a FG around 1.020 and ABV of 5.25%. This is assuming an initial reading of 1.060 (14.5 brix) and final reading of 8.8 brix.

The amylase enzyme might fix the pale and could drop the brown a tad.

 

[Yooper]

Doh! Never even knew I had to do an alcohol correction. The instructions with the refractometer didn't even mention that and it is specifically a brewing model.

Even with that correction calculator, the brown is 1.1% ABV short of target and the Pale is 4% off.

Why not humor us and run and take a hydrometer reading of the pale? I'd be curious to see if the correction is accurate.

I use my refractometer preboil (it's great for that), and post boil, prefermentation. Even with the corrections, it's not accurate enough for post-fermentation readings to be of any use. It will tell you that it's stopped changing, but it's pretty useless for FG readings. That's why I still use a hydrometer for the FG.

 

[helibrewer]

My hydrometer and refractometer (both temp corrected) are usually within .002 of each other. By using the refractometer I can hold off and only take 1 hydrometer reading at the very end once the refractometer reading no longer changes.

 

[rhamilton]

Why not humor us and run and take a hydrometer reading of the pale? I'd be curious to see if the correction is accurate.

I use my refractometer preboil (it's great for that), and post boil, prefermentation. Even with the corrections, it's not accurate enough for post-fermentation readings to be of any use. It will tell you that it's stopped changing, but it's pretty useless for FG readings. That's why I still use a hydrometer for the FG.

WTFBBQSAUCE!

Hydrometer clocked in at 1.012 for the pale -- exactly what was expected; didn't test the brown but I plan to retest every keg tonight. Recalibrated the refractometer and retested the pale with the same beer from the hydrometer tube -- still came in at 10 brix (1.040).

*grrr* I bought the refractometer so I wouldn't have to waste so much beer to take a measurement. Now I have a perfectly good beer with an extra 2 tsp of enzyme in it

 

[pabloj13]

WTFBBQSAUCE!

Hydrometer clocked in at 1.012 for the pale -- exactly what was expected; didn't test the brown but I plan to retest every keg tonight. Recalibrated the refractometer and retested the pale with the same beer from the hydrometer tube -- still came in at 10 brix (1.040).

*grrr* I bought the refractometer so I wouldn't have to waste so much beer to take a measurement. Now I have a perfectly good beer with an extra 2 tsp of enzyme in it

It came in at 1.040 AFTER the correction for alcohol in solution?

 

[Yooper]

WTFBBQSAUCE!

Hydrometer clocked in at 1.012 for the pale -- exactly what was expected; didn't test the brown but I plan to retest every keg tonight. Recalibrated the refractometer and retested the pale with the same beer from the hydrometer tube -- still came in at 10 brix (1.040).

*grrr* I bought the refractometer so I wouldn't have to waste so much beer to take a measurement. Now I have a perfectly good beer with an extra 2 tsp of enzyme in it

Yes, that was what I was afraid of! That's one of those "live and learn" things- but I DID try to stop you!

Even with "corrections", alcohol can really skew the readings. I actually started with wine long before beer, and I did learn a couple of good things about the refractometer. For example, even when it's "wrong" with a reading, once it stops changing, it's done. THEN you can take a hydrometer reading for the actual FG. So you only need one FG reading, and a total of one hydrometer reading per batch since you can use the refractometer pre-fermentation and even until it's unchanging post-fermentation. Then, you know you're at FG, even if the reading itself is incorrect. I hope that makes sense- I don't think I"m explaining it well.

 

[rhamilton]

It came in at 1.040 AFTER the correction for alcohol in solution?

1.040 before correction, 1.0356 After correction. Still way way way way off.

 

[rhamilton]

Yes, that was what I was afraid of! That's one of those "live and learn" things- but I DID try to stop you!

Even with "corrections", alcohol can really skew the readings. I actually started with wine long before beer, and I did learn a couple of good things about the refractometer. For example, even when it's "wrong" with a reading, once it stops changing, it's done. THEN you can take a hydrometer reading for the actual FG. So you only need one FG reading, and a total of one hydrometer reading per batch since you can use the refractometer pre-fermentation and even until it's unchanging post-fermentation. Then, you know you're at FG, even if the reading itself is incorrect. I hope that makes sense- I don't think I"m explaining it well.

Definitely makes sense. Use the refractometer to show fermentation has stopped. Once it's stopped, use the hydrometer for the FG so over the course of a brew, you only lose 1 hydrometer sample instead of multiple. So is the refractometer 100% reliable for OG calculations?

 

[rhamilton]

Also, would a digital refractometer prevent these inaccurate readings?

 

[brewit2it]

Yes, that was what I was afraid of! That's one of those "live and learn" things- but I DID try to stop you!

Even with "corrections", alcohol can really skew the readings. I actually started with wine long before beer, and I did learn a couple of good things about the refractometer. For example, even when it's "wrong" with a reading, once it stops changing, it's done. THEN you can take a hydrometer reading for the actual FG. So you only need one FG reading, and a total of one hydrometer reading per batch since you can use the refractometer pre-fermentation and even until it's unchanging post-fermentation. Then, you know you're at FG, even if the reading itself is incorrect. I hope that makes sense- I don't think I"m explaining it well.

Yes, it makes total sense and you explained it well. Bottom line, it's great for pre-fermentation gravity readings and can tell you when you're at terminal gravity, but don't trust it to give you an accurate reading of FG.

 

[Yooper]

Definitely makes sense. Use the refractometer to show fermentation has stopped. Once it's stopped, use the hydrometer for the FG so over the course of a brew, you only lose 1 hydrometer sample instead of multiple. So is the refractometer 100% reliable for OG calculations?

Yes, it is. As long as it's calibrated, of course. I also have a "hydrometer correction factor" in my Beersmith refractometer tools, of .01544 so that my hydrometer and refractometer give me the same reading. The first time I used them together, I took a preboil reading of the wort (cooled) with both. Since I got 10.8 on the refractometer, and 1.043 with the hydrometer (both of which were previously calibrated with distilled water), the correction factor was plugged into my software. Otherwise, it's still very close but I'm sort of anal about things.

So now, if I take a pre-fermentation reading of 11.4 with my refractometer, it is guaranteed to be 1.045 on my hydrometer.

 

[Yooper]

Also, would a digital refractometer prevent these inaccurate readings?

I don't think so. Since refractometers simply "read" light refraction, alcohol can still skew it.

 

[pabloj13]

1.040 before correction, 1.0356 After correction. Still way way way way off.

How are you doing the correction? Edit: Nevermind. I guess you're probably using that site above.