Possible Stuck Fermentation -

[pannell77]

I have a left hand milk stout clone going right now and it appears that fermentation has come to a halt. It has been holding steady at 1.03 for a few days now.

Originally brewed on 7/21 with an OG of 1.06, pitched a 1L starter of white labs WLP001 at 72F, fermentation kicked off after about 8 hours and is now holding pretty steady. There is little to no airlock activity but still some bubbling on the surface. Fermenting temps are around 67-70 during the day.

Should I possibly re-pitch some yeast? I have tried "gently" rousing the yeast by slowly swirling the bucket around.

The issue I have with re-pitching is that I do not have any WLP001 on hand. I have the following yeast strains that I washed from previous batches however:

White Labs 028 - Edinburgh Ale
Wyeast 1028 - London Ale
Wyeast Greenbelt
Danstar Nottingham

 

[hercher]

Can you post your recipe? Since it is a milk stout, I'm assuming you added lactose, which is not fermentable. So it is possible that fermentation isn't stuck, but is actually finished.

 

[pannell77]

Can you post your recipe? Since it is a milk stout, I'm assuming you added lactose, which is not fermentable. So it is possible that fermentation isn't stuck, but is actually finished.

I don't know the exact recipe since it was an all grain kit from Austin Homebrew Supply for a Left Hand Milk Stout. It did have a lactose addition at the end of the boil. I will look at the instruction sheet when I get home to see if it has any more specific details.

 

[chitownbrewer]

I once had an IPA that stopped bubbling within a couple of days which seemed odd to me since I've always seen them stop at around a week. Anyway, I reracked it and the fermentation took off again. I think the first time around there might not have been enough oxygen in the wort to support a full fermentation. When I reracked it I must have introduced more oxygen and the yeast took off again. Give it a try maybe it will work for you.

 

[duboman]

It is quite possible it just needs a little more time to get the last points out of it.

At what temperature did you mash? Is your thermometer and hydrometer calibrated and did you adjust for temperature? With a high mash temperature you may have a less fermentable wort and with the lactose addition you may not get what is expected even if a proven recipe.

If it is still bubbling a bit then it is probably still fermenting a bit, did the krausen drop yet? It's only been about ten days, I would give it more time

 

[beergolf]

Can you post your recipe? Since it is a milk stout, I'm assuming you added lactose, which is not fermentable. So it is possible that fermentation isn't stuck, but is actually finished.

Since you mention that there is still some bubbling on the surface it may still be working. However, It is possible that it is done. Let it sit for another week and if it does not drop it may be done. Brews with a lot of lactose often finish pretty high. I never had one stop at 1.030, but have had one stop at 1.027. That one had a pound of lactose in it.

 

[pannell77]

this one had a pound of lactose in it so you may be correct that it is done.

 

[JLem]

this one had a pound of lactose in it so you may be correct that it is done.

A pound of lactose will increase the FG of a 5 gallon batch by 6-8 points, so 1.030 still seems high. What was your mash temp? And how much specialty malt, especially crystal types? Any DME or LME in the recipe?

 

[pannell77]

I mashed at 147-150, it fluctuated a bit to start and I got it to hold at 150 for 60min. My cooler converted mash tun didn't insulate so well, i ended up wraping a blanket around it and putting 2 layers of foil on top of the grain to try and trap it in.

Here is the grain bill according to the kit instructions:
7.75lb pale ale malt
.75lb munich malt
1lb black roasted barley
10oz flaked barley
.75lb crystal 60
.75lb chocolate malt
.5lb flaked oats

1lb lactose at boil

.75oz magnum at boil
1oz kent golding 10min

 

[JLem]

I mashed at 147-150, it fluctuated a bit to start and I got it to hold at 150 for 60min. My cooler converted mash tun didn't insulate so well, i ended up wraping a blanket around it and putting 2 layers of foil on top of the grain to try and trap it in.

Here is the grain bill according to the kit instructions:
7.75lb pale ale malt
.75lb munich malt
1lb black roasted barley
10oz flaked barley
.75lb crystal 60
.75lb chocolate malt
.5lb flaked oats

1lb lactose at boil

.75oz magnum at boil
1oz kent golding 10min

I just punched this into BeerSmith. For a 5 gallon batch, assuming 70% efficiency, the expected OG without the lactose is 1.063. More importantly, the estimated FG without the lactose is 1.011. This means that with the lactose, you should expect an FG in the 1.017 - 1.019 range. 1.030 is definitely too high.

I would give it another week and see if it comes down at all. You could try gently rousing the yeast and/or bumping up the temperature some. If it stays at 1.030 or you feel like going ahead with adding more yeast, I would rehydrate the Nottingham and pitch that. I'd save the liquid yeast for other brews. If you decide to use one of the liquid yeasts, be sure to make a starter since the yeast need to be nice and healthy going into an inhospitable environment (low pH, low O2, alcohol present).

Good luck.

 

[pannell77]

Thanks for the help JLem. I will raise up the temps and swirl it around some and see if it starts moving down at all, if not I will pitch the nottingham and hope for the best.

 

[pannell77]

I took my fermenter out of the ghetto swamp cooler, sanitized my mixing paddle and gave it a good slooooow mix to stir everything up and a couple hours later I got some airlock activity going on. hopefully it keeps up and finishes out where it is supposed to.

 

[pabloj13]

I took my fermenter out of the ghetto swamp cooler, sanitized my mixing paddle and gave it a good slooooow mix to stir everything up and a couple hours later I got some airlock activity going on. hopefully it keeps up and finishes out where it is supposed to.

Just keep in mind that stirring and raising the temp are going to knock CO2 out of solution, causing airlock bubbling.