Stuck fermentation with D-47

[willowhix]

Hey guys. This is my first go at mead and so far it's been going well, if a little slow. However the amount of bubbling has been slowly decreasing, and after checking the gravity the other day it seems to have stopped completely, though it's not nearly as low a gravity as I'm looking for. So, it's stuck. I'm in need of some advice on how to un-stick it.

Original recipe - http://www.gotmead.com/forum/showthr...e-any-problems Should apparently be medium-sweet when finished.
The yeast used was D-47
The ferment is 26 days in, and stopped bubbling about five days ago.
Original SG - 1.120
SG five days ago - 1.054
pH five days ago - 3.2 (pH measurement at pitch wasn't accurate)

A few things that might have caused the batch to stall:

- The temperature in Glasgow dropped a lot in the past few days. Since I'm brewing in my eaves (which previously was a good consistent temperature), I believe it's dropped lower than it really should be.
- My initial measurement of fermaid wasn't as accurate as I'd have liked. It's possible I've added a little too much or too little. If it's the latter, I guess it could be affecting the yeast in this later stage of primary.
- Although the fermentation did seem to slow down over time (as opposed to stopping within one day), it wasn't until I had opened the fermenting bucket for the first time since pitching that it actually stopped. I don't see how this could have caused it to stall, but it does seem worth mentioning.
- EDIT: I've also not been stirring my must at all since the pitch (when I was aerating). I've read on the forums that this keeps the yeast in suspension. Perhaps the lack of stirring may have contributed?

So, I've ordered some more Lalvin D-47, and my plan is to rehydrate the yeast and pitch again into the half-finished must, add another 1 or 2 grams of fermaid and try to keep the temperature within a good range by paying close attention and moving it out of the eaves into the next room when its too cold.

What I'm not sure about is whether or not I should rack the must into a new container beforehand in case the lees from the old yeast starts to give it bad flavours, whether I need to aerate the must again for the new yeast and whether this is a good plan in the first place. Any advice would be greatly appreciated.

 

[Mazer828]

Hey guys. This is my first go at mead and so far it's been going well, if a little slow. However the amount of bubbling has been slowly decreasing, and after checking the gravity the other day it seems to have stopped completely, though it's not nearly as low a gravity as I'm looking for. So, it's stuck. I'm in need of some advice on how to un-stick it.

Original recipe - http://www.gotmead.com/forum/showthr...e-any-problems Should apparently be medium-sweet when finished.
The yeast used was D-47
The ferment is 26 days in, and stopped bubbling about five days ago.
Original SG - 1.120
SG five days ago - 1.054
pH five days ago - 3.2 (pH measurement at pitch wasn't accurate)

A few things that might have caused the batch to stall:

- The temperature in Glasgow dropped a lot in the past few days. Since I'm brewing in my eaves (which previously was a good consistent temperature), I believe it's dropped lower than it really should be.
- My initial measurement of fermaid wasn't as accurate as I'd have liked. It's possible I've added a little too much or too little. If it's the latter, I guess it could be affecting the yeast in this later stage of primary.
- Although the fermentation did seem to slow down over time (as opposed to stopping within one day), it wasn't until I had opened the fermenting bucket for the first time since pitching that it actually stopped. I don't see how this could have caused it to stall, but it does seem worth mentioning.
- EDIT: I've also not been stirring my must at all since the pitch (when I was aerating). I've read on the forums that this keeps the yeast in suspension. Perhaps the lack of stirring may have contributed?

So, I've ordered some more Lalvin D-47, and my plan is to rehydrate the yeast and pitch again into the half-finished must, add another 1 or 2 grams of fermaid and try to keep the temperature within a good range by paying close attention and moving it out of the eaves into the next room when its too cold.

What I'm not sure about is whether or not I should rack the must into a new container beforehand in case the lees from the old yeast starts to give it bad flavours, whether I need to aerate the must again for the new yeast and whether this is a good plan in the first place. Any advice would be greatly appreciated.

I'm not the guy to ask. D47 does this to me too, without reason that I can figure. I will be watching hopefully for some of the mead savants to chime in with some insight!

(Grabs glass of mead, waits for savant to show up.)

 

[willowhix]

I'm not the guy to ask. D47 does this to me too, without reason that I can figure. I will be watching hopefully for some of the mead savants to chime in with some insight!

(Grabs glass of mead, waits for savant to show up.)

Haha. Well, I'll wait with you Mazer828, but in my hand I'll have a beer. This is my first batch after all.

Now you've said you've had the same problem and no solutions. What have you tried in the past? Did you do the whole repitching yeast to get it going again?

 

[Mondor]

What is ambient temperature and the temperature of the must? My understanding is that D47 works best below 70f. That may be something to look at.

Edit to add info I snagged from Lallemand

Yeast Strain
Lalvin ICV D47

Ferment Vigour
Moderate

Nitrogen Demand
Low

Ferment Temp Range
15 - 20 C

 

[Squatchy]

So you need to give us more info so we can help. How did you rehydrate, what protocol and what ingredients did you rehydrate in? Did you atemperate your yeast slurry to within 10 degrees of each other before you pitched? Bubbles, or lack of don't tell you a damn thing. You need to use your hydrometer. Have you tried just warming up your batch a little and stirred it to see what happens?

You don't just want to repitch. That's not the way. Go find the Scott Labs Yeast booklet. In there is a complete chapter telling you how to restart a stuck batch.

Go measure your stuff,, look up the chapter and then report back

 

[Mazer828]

Haha. Well, I'll wait with you Mazer828, but in my hand I'll have a beer. This is my first batch after all.

Now you've said you've had the same problem and no solutions. What have you tried in the past? Did you do the whole repitching yeast to get it going again?

Yeah the last time I used it was with a traditional mead, with the intent being a moderate 10-11% ABV final product. I used one packet of D47, which I actually started overnight in an 800mL 1.040 gravity malt extract starter. The yeast was very happy the next morning when I pitched. The must temp was right around 68F. It fermented well almost immediately and i added 3 tsp Fermax to keep things happy. I The OG was somewhere around 1.080. Two days later it just quit at 1.055. Yeast dropped and there was no apparent reason why. I added 2 tsp Fermax, oxygenated again, and pitched some reclaimed yeast of another strain I'd had more experience with and knew would do the job (wyeast dry mead). That got it going and took it right down to the FG I wanted.

Haven't used D47 again since, but I really want to, so I can figure out how others are getting such good results. I've been reading and listening (got.mead live!) about TOSNA, and I think that might be the ticket.

I feel an experimental batch coming on!

 

[willowhix]

Hey Mondor! The ambient temperature has remained pretty consistently at 16 deg C, up until a few days ago, when it started dropping. It's now about 12 deg C at night. Curiously though, the must was still sitting at 16 deg C when it slowed down and stopped, so I'm not 100% sure the temperature can be blamed (though it's possible it dropped lower at night than I thought). It's never been above 20 deg C.

Squatchy, I've not given those details because I've not done any yeast re-pitching yet. I'll try warming the must up and giving it a stir and let you know if that does anything, and I'll definetely try get a hold of that reading when I can. Thanks for that.

Interesting stuff Mazer, I'm inclined to think that if I do decide to repitch, I might try find a different strain with better chances just to be on the safe side.

 

[pokerfacepablo]

pH of 3.2 is on the low side. Take another reading to be sure and then adjust with some bicarbonate before repitching.

Sent from my SM-G920V using Tapatalk

 

[EJM3]

I used D47 for most of my needs in the wintertime, we have an old (103 years) house that has plenty of cold spots. I generally try and ferment D47 around 62°F to 64°F (17°C - 18°C), but it as a bit temperamental with cold. If it does go below 60°F (15°C) then it likes to fall out & nap, you normally just have to warm it back up and give it a good rousing.

I'm with pokerfacepablo on the pH of 3.2 being pretty low, I know that a pH of 3.0 can stall out a ferment; you probably just need to raise the pH by a small addition of K2CO3 (Potassium Carbonate). I'd advise on approximate amounts but my skills are a bit lacking right now, it's been almost 9 months since I've been able to get a mead under way (6 beers though!). Just remember that after adding a small amount you may not see a big change right away, wait for an hour then try testing the pH before adding more (too much).

I was unable to click on the link to get the recipe, am I the only one??

 

[willowhix]

http://www.gotmead.com/forum/showthread.php/25101-Just-started-my-first-batch-Do-I-have-any-problems

Perhaps that'll work. If it doesn't, it's just Ken Schramm's reccomended orange blossom recipe for your first mead in The Compleat Meadmaker, scaled down and with substitutions for nutrients and yeast.

 

[Crowing]

D-47 always goes well past 14% for me, and my first ever batch was fermented at about 58 degrees. You're getting to 53 or lower at night, I'm guessing that's the biggest problem, when mine got that cold last winter they went to sleep for awhile. Also, squatchy was asking about rehydration of your initial pitch, which if you didn't do at all or didn't use goferm could mean your yeast just weren't up to the job. If you haven't already, but bring his somewhere warmer, if you stir it do so gently, and before anything at all, make sure to take gravity readings over the course of a week because it could be going on and fermenting very slowly.

 

[willowhix]

Ahh, I see. My mistake. I did hydrate my yeast as the instructions on the packet said, two packets in 100mL of water, although I did leave them there for roughly 20 minutes when the packet asked for 15 minutes. Either way, the ferment started off just fine at the time.

 

[Squatchy]

Even if it did start out what seemed to be fine you may still have started out with crippled yeast. the 5 minute difference wouldn't make any difference if your talking 15 or 20 minutes. They build the yeast with some added stuff so that they are somehow very ambitious for the first 30 minutes and then they run out of the built in advantage. So with that said they instruct to pitch before the 30 minutes runs out. This is Lallemende (sp) yeast

 

[Mazer828]

Even if it did start out what seemed to be fine you may still have started out with crippled yeast. the 5 minute difference wouldn't make any difference if your talking 15 or 20 minutes. They build the yeast with some added stuff so that they are somehow very ambitious for the first 30 minutes and then they run out of the built in advantage. So with that said they instruct to pitch before the 30 minutes runs out. This is Lallemende (sp) yeast

Never knew that. Interesting.

 

[willowhix]

Even if it did start out what seemed to be fine you may still have started out with crippled yeast. the 5 minute difference wouldn't make any difference if your talking 15 or 20 minutes. They build the yeast with some added stuff so that they are somehow very ambitious for the first 30 minutes and then they run out of the built in advantage. So with that said they instruct to pitch before the 30 minutes runs out. This is Lallemende (sp) yeast

Seconded. That's some very good information. I'll be sure to be aware of that in future batches.

 

[willowhix]

So, I've been keeping an eye on the must, trying to keep it at a good temperature and taking some hydrometer measurements:

0 days - 1.120
21 days - 1.054
35 days - 1.047
37 days - 1.045
38 days - 1.044

So it's still going, just very slowly. I checked the pH again and the second strip agrees that it's pH 3.2. People are suggesting I add bases to balance out the pH. Does that do anything to the flavour of the mead? I wasn't planning on using any chemicals to begin with but I'm starting to think I don't have much of a choice.

I've also had a look at that booklet Squatchy suggested. http://www.scottlab.com/pdf/ScottLabsHandbook2013.pdf I could try restart fermentation this way if I need to, but I feel the pH issue is probably the main one right now so I'll need to sort that out first.

Is it possible I could fix this batch by repitching with a different strain of yeast, and would it be a good idea?

 

[Mazer828]

Man that looks just like what D47 does to me every time! Agh! At 38 days you should be much lower than that.

 

[Squatchy]

I would suggest getting potassium carbonate to adjust for your pH. Then I would stir it up (not very aggressively) some to get the yeast up in suspension. (you always want them up in suspension BTW). Go look and see what the temp range is and bring it up to with 10 degress of the max for a day or so and see what happens. You haven't told us if it stinks or taste bad/hot.??? Normally a good ferment would take approximately 2 weeks to eat through 140 points or more. You could extend that some by design if you keep it close to the minimum range. Never the less, you have a problem. You might also want to boil a couple packets of bread yeast (Flieshmans) in a tiny bit of water. Bring .5 cup to a full boil and dump 2 packs of yeast in it. Let it cool to room temp and add it to your batch.

Make sure to measure your gravity first so you can check it to see if it gets going again. If you have burnt up 75 points your ABV is close to 10%. Not sure how a new batch of yeast would like starting out in that high of an alcohol start. I would use the protocol in the handbook if you end up needing to restart it with more than what I just wrote up above.

Keep us posted as we can all learn with things like this being posted

Yeast are broken into 3 different (combat categories) that's what I call it
Some are aggressive and will fight other yeast (bad idea if you like to drink it)
Some are passive. They just sit around stoned all the time and don't give a dang
And some are sissy's and die if someone looks at them. If you want to "blend " different yeast in the same batch you better make sure who the neighbors are. You may end up with a civil war on your hands.


That would be fun in something considerably cheaper. We should have a new category for competition. A "Foulomel" "smellomel" "warchette" "pission" "dyement" "asserglyn"

 

[willowhix]

Oh, thanks very much! Lots of useful information here. It doesn't taste bad or hot to me, but I've never tried unfinished mead until I started this so I've nothing to compare it to. I have been trying to keep it consistently at about 18-19 deg C. Apparently the range is 15-20 deg C for D47. It's been quite challenging but the lowest it ever drops is 15 deg C and the highest is 19 deg C, so it's an improvement from the setup I had before it got cold here. I have also been stirring it gently to resuspend the yeast every couple of days. Curiously, it goes through periods of bubbling once every few minutes for a while and then periods of not bubbling at all. I'm not entirely sure what to make of that, though I assume temperature changes are contributing somewhat.

The bread yeast thing sounds interesting. Is that supposed to add more nutrients to try get the yeast going again? If so, why not just add more nutrient?

I'm surprised that my mead is about 10% according to your calculations. I hadn't really given it much though, but I was expecting it to finish around 13% like a typical red wine. If it still has a lot of fermenting to go, I guess it will be quite strong if I can get it finished! Nevertheless I'm alright with that. It's too sweet right now to be considered "good enough". I'm not done with it yet.

Does potassium carbonate change the flavour of the mead at all? If not, I'm happy to get my hands on some and add it right away, but otherwise I'm not so sure. I might see if I can go without it for a bit. I was originally not planning on using chemicals at all.

 

[Squatchy]

So yes. The dead yest will give it organic yeast that will just drop out at some point. More nutrient might leave a metallic taste behind. The PC will bring your pH back in range so the yeast can go back to work if the pH is the problem.