To Rouse or not to rouse

[CA_Mouse]

I have a Milk Stout that seems to have done something completely unexpected. OG was 1.056. I pitched a 1 liter starter with WLP004 Irish Ale Yeast. It was vigorously fermenting within 6 hours, so much so that I had to switch from an airlock to a blow off tube. It continued to go for another 12 hours or so and then stopped completely. I waited until it had been in the carboy for 2 weeks and took a sample. This is where I'm concerned. Sample was 1.052! I waited 2 days and sampled again... Still 1.052. Waited another 2 days and still at 1.052. Racked it off the yeast and repitched a 2 liter starter of the same yeast. 24 hours later and there doesn't appear to be anything happening (no activity through the blow off tube). Temperature is just below 69F and has been pretty constant for the last 3 weeks. My last Milk Stout was nearly perfect (only change was adding 4 oz of Maltodextrine to increase the mouth-feel without taking the ABV higher.

Suggestions as to what may have happened or how to get it to finish out properly? I can't see 4 oz of Maltodextrine being the cause of it only dropping .004 in three weeks.

Mouse

 

[beergolf]

If it was going so fast and furious that you needed a blow off tube, there is no way it only dropped 4 points.

How are you taking your readings. Are you using a hydrometer or a refractometer? Have you checked your hydrometer for accuracy?

 

[Cyclman]

Refractometers have to have adjustment calculations if used for beer (as opposed to wort): http://seanterrill.com/2012/01/06/refractometer-calculator/

+1 on I can't fathom how you could have such active fermentation with minimal gravity drop. How's it taste?

 

[CA_Mouse]

I did not taste it. Initial reading was before fermentation with my refractometer, hydrometer after that, as normal. I brewed an Irish Blonde with the same yeast (actually made a 2 liter starter and split it between both beers) that one was 1.048 OG and finished at 1.008 as expected. Brewed 2 days apart and shared the same closet during the fermentation. The Stout had a slight soy sauce smell when I racked it off the original yeast cake. There is some pressure in the bucket, but not enough that it is blowing bubbles.



Mouse

 

[kh54s10]

It is totally not possible that with the need of a blow off tube you only dropped .004. Are you using a refractometer for you fg? If so you need to correct for alcohol content. Are you correcting for sample temperature. There is something going wrong in the taking samples and reading of the gravity.

 

[CA_Mouse]

It is totally not possible that with the need of a blow off tube you only dropped .004. Are you using a refractometer for you fg? If so you need to correct for alcohol content. Are you correcting for sample temperature. There is something going wrong in the taking samples and reading of the gravity.

I don't think that you have read my posts. Temperature was 69F. OG was measured with a refractometer at 68F when the yeast was pitched. Temperature has been steady and all post yeast readings have been with a hydrometer. Same yeast used on another beer (Blonde Ale) brewed 2 days after the Stout also needed a blow off tube and fermented perfectly. Readings were made with the same equipment at the same temperatures. An APA brewed 2 days prior to the Stout had no issues either. This has nothing to do with my hydrometer or my OG reading. The Stout only fermented for for about 18 hours and quit. Repitching the Stout with a fresh Starter of the same yeast has failed to produce any apparent airlock activity in 3 days. The Blonde Ale using the same yeast had airlock activity for 4 days before it finally stopped. A 4th beer brewed 2 weeks later using the same yeast just finished getting transferred to secondary for dry hopping and using the same equipment OG was 1.062 and 1.012 when transferred for dry hopping.

Mouse

 

[beerbeer95648]

I would pull 250ml for doing a quick and dirty forced fermentation on the stout. Was this an all grain beer? If so I would dilute a little on a plate and do an iodine test on it for fun. Barring a broken hydrometer (doesnt sound like it) or a gross mistake in the maltodextrine amount, I cant imagine this stopping at 1.052. Like I said I would take some into a flask, add a bit more yeast if possible and put it on a stir plate, or shake it routinely somewhere warm and see if it drops at all. I make a point of doing a forced with every brew I make.

 

[CA_Mouse]

I would pull 250ml for doing a quick and dirty forced fermentation on the stout. Was this an all grain beer? If so I would dilute a little on a plate and do an iodine test on it for fun. Barring a broken hydrometer (doesnt sound like it) or a gross mistake in the maltodextrine amount, I cant imagine this stopping at 1.052. Like I said I would take some into a flask, add a bit more yeast if possible and put it on a stir plate, or shake it routinely somewhere warm and see if it drops at all. I make a point of doing a forced with every brew I make.

I've never pulled a sample to force additional fermentation. I've generally been able to ferment out all my beers. As far as the maltodextrine, I use a digital scale that I calibrate monthly. I verify my hydrometer about every 6 weeks in distilled water at several temperatures to ensure I know what range it would be off at what temperature. How much added yeast are you talking about adding? I would be fine with pulling a larger sample even.

Mouse

 

[beerbeer95648]

For me, I normally keep the vial or pouch in the fridge after pitching the yeast into my starter. I then run a 250ml (amount it takes to fill my hydrometer jar) of cool wort from the batch into a flask. I then transfer a little into the vial and shake, then add back to the flask and put it somewhere warm on a stirplate. The benefit is that you are giving the flask the best chance of fermenting the sample to its intended terminal gravity. You can then compare the gravity of the sample to the bulk fermentation. This will separate out fementability issues from yeast derived problems. As an example, I thought I had a yeast health issue one time when a stout I brewed only dropped to 1.020, but after the forced sample finished at 1.020 as well I realized that my mashtun thermometer was off meaning I mashed at 158 degrees. In terms of how much yeast for you to add at this point, I would just add anywhere from a tsp to a tbsp in 250mls. More is better since you are not trying to emulate the main fermentation, you just find out what the potential final gravity is. Youll just want to use the same strain yeast.

 

[nstnate]

Would you say there was an abnormally high amount of blow off? I had a barley wine do this with a different yeast, my best guess was that it blew off so much of the next gen of yeast it stalled out, I was not able to get it restarted either.

 

[CA_Mouse]

Would you say there was an abnormally high amount of blow off? I had a barley wine do this with a different yeast, my best guess was that it blew off so much of the next gen of yeast it stalled out, I was not able to get it restarted either.

I was thinking that may be the cause as well. All 4 times I have brewed this stout I have had very aggressive blow off. First time it blew the lid off the fermenting bucket and I found out 2 days afterward (fermenting in a refrigerator that I checked in the morning and again 2 days later) that one was infected and dumped. Next one was fine with a lot of blow off (lost about 3/4 of a gallon). 3rd one blew the lid off, but was caught immediately since it was in a hallway closet and sounded like a bowling ball crashed into the wall (ended up the best of the Stouts so far). Now this one... Blow off loss was about 1/2 gallon. I am thinking that it chunked so much and so hard that it blew off most of the yeast (the yeast cake did not look to be as think as the previous 2 batches and was not as thick as the yeast cake on the Blonde Ale brewed 2 days after the Stout).

Mouse

 

[CA_Mouse]

For me, I normally keep the vial or pouch in the fridge after pitching the yeast into my starter. I then run a 250ml (amount it takes to fill my hydrometer jar) of cool wort from the batch into a flask. I then transfer a little into the vial and shake, then add back to the flask and put it somewhere warm on a stirplate. The benefit is that you are giving the flask the best chance of fermenting the sample to its intended terminal gravity. You can then compare the gravity of the sample to the bulk fermentation. This will separate out fementability issues from yeast derived problems. As an example, I thought I had a yeast health issue one time when a stout I brewed only dropped to 1.020, but after the forced sample finished at 1.020 as well I realized that my mashtun thermometer was off meaning I mashed at 158 degrees. In terms of how much yeast for you to add at this point, I would just add anywhere from a tsp to a tbsp in 250mls. More is better since you are not trying to emulate the main fermentation, you just find out what the potential final gravity is. Youll just want to use the same strain yeast.

I may just pull 1000 ml sample and put it on the stir plate, I don't think I have much to lose at this point. Still no activity in the blow off tube/bottle after re-pitching last Sunday morning.

Mouse

 

[beerbeer95648]

Excessive blow-off may slow a fermentation, but it shouldn't stop one. Especially if you re-pitched and saw no added activity. I am at a loss really. Hopefully, getting a forced fermentation going will shed some light. Normally I would have said get a healthy well aerated starter going and add it in the fermenter and you would be fine. Did you ever say if this was an extract or all grain? Have you tasted it lately?

 

[CA_Mouse]

It was an All Grain batch. When I pitched the additional yeast, it was a full 2 liter starter straight from my stir plate, so I believe that it was well aerated. The weird part is that there is pressure building up, just not enough to cause bubbles in the blow off bottle. I have it in a 6.5 gallon fermentation bucket and the lid is slightly domed with the built up pressure.

As for the excessive blow off, I think that it may have taken too much of the yeast with it, since it basically stopped fermenting in less than 24 hours.

Mouse

 

[nstnate]

It was an All Grain batch. When I pitched the additional yeast, it was a full 2 liter starter straight from my stir plate, so I believe that it was well aerated. The weird part is that there is pressure building up, just not enough to cause bubbles in the blow off bottle. I have it in a 6.5 gallon fermentation bucket and the lid is slightly domed with the built up pressure.

As for the excessive blow off, I think that it may have taken too much of the yeast with it, since it basically stopped fermenting in less than 24 hours.

Mouse

I did the same with a starter for my stalled barley wine, got a few bubbles but no go. i did taste after adding the starter and it also had messed up the hopping by adding all the extra yeast.

 

[DPBISME]

Your TEMPS seem fine...

I also like the idea of a follow up starch test.

Did we taste it yet? I mean it sounds lie an equipment problem to me...

Maybe if it turns out that in fact you yeast went dormant that next time you use a smaller starter.

For my High Gravity Beers I pitch low amounts and start very cool so I don't have a blow off... I would rather have a noce steady fermentation than one as violent as you describe.

I mean you could pull a sample, areate it, and toss some Champagne yeast on it... if it does not start to bubble then my guess is it was done all along or you did not have complete conversion.

 

[nstnate]

Your TEMPS seem fine...

I also like the idea of a follow up starch test.

Did we taste it yet? I mean it sounds lie an equipment problem to me...

Maybe if it turns out that in fact you yeast went dormant that next time you use a smaller starter.

For my High Gravity Beers I pitch low amounts and start very cool so I don't have a blow off... I would rather have a noce steady fermentation than one as violent as you describe.

I mean you could pull a sample, areate it, and toss some Champagne yeast on it... if it does not start to bubble then my guess is it was done all along or you did not have complete conversion.

Would your hydrometer or refractometer read the the same gravity if the starches were unconverted? Would think the gravity would be less?