3 ideas for stuck fermentation

[NavySur4]

I brewed a NB Scottish 80 with S-33 yeast. SG was 1.051 and fermentation went well for the first 3 days. After that the temps dropped and I'm pretty sure fermentation is stuck - been 1.020 for the past week. I've tried swirling and stirring the yeast back up - no change.

My 3 ideas are:

1) I can bottle an Irish Ale tonight (4 weeks in primary) and rack the scottish onto the yeast cake. Yeast in Irish Ale is S-04.

2) rehydrate another pack of S-33 and repitch

3) leave it alone and keg after 3 weeks (worried about this since I took off the lid to stir so CO2 was released)

My hydrometer is correct and I've read many threads but they seem to contradict each other. Some say re pitch some say don't, some say rack on a yeast cake some don't.

Thanks for the help and any ideas.

Mike

 

[Revvy]

1.020 is an acceptable, and quite common final gravity. It probably isn't stuck, just finished. I've bottle plenty of extract batches in my day that were 1.020.

 

[bknifefight]

What was your expected FG? 1.020 does seem high but depending on your recipe, it may not be too far from being finished. Post your recipe as well.

From your ideas, I would go with the first. If the yeast is the same, go ahead and rack it onto the yeast cake. When you are siphoning into the fermenter, the yeast will get roused up into the beer and hopefully they will wake up and realize dinner has been served.

 

[nilo]

Couple things.
-Post your recipe so people can evaluate your FG
-You said your temp droped. Give numbers.
Your beer is probably finished, no further action required other than bottle/keg.

 

[NavySur4]

Thanks Revvy, but will there be a problem with the lack of CO2 to protect the brew since I took the top off and let it out when I stirred?

bkn - not sure what the FG is supposed to be since it's not listed on the NB website or the instructions they sent. I would guess about 1.012.

 

[NavySur4]

temps started at 67-68, dropped into upper 50's (cold spell in SOCAL). Started in my garage but moved into house and it warmed to 68.

 

[nilo]

Is this the all grain kit from NB? I only found an AG kit for a scottish 80 there, no extract kit. If it is, this is the info I got there:
MASH INGREDIENTS
-- 9 lbs. Simpson’s Golden Promise
-- 1 lbs Simpsons Medium Crystal

MASH SCHEDULE: SINGLE INFUSION
Sacch’ Rest: 153° F for 60 minutes
Mashout: 170° F for 10 minutes

OG 1.047 READY: 6 WEEKS

If I plug this to my brewing tool the expected FG would be 1.012.

I would just warm it back to 68F, stir and let it sit for another week, then re-check gravity.

 

[Revvy]

If I plug this to my brewing tool the expected FG would be 1.012.

I would just warm it back to 68F, stir and let it sit for another week, then re-check gravity.

Don't stir, keep the fermenter closed and give it a gentle swirl to re-rouse the yeast. You don't want to risk oxidation by stirring.

Other than that, Nilo is dead on if it is an AG recipe.

If it is extract I'd say it is the 1.020 curse, and it is done.

 

[NavySur4]

Sorry, I was rushed this morning. It is the extract with specialty grains scottish 80 from Northern Brewer. Thanks for the advice and I'll leave it alone and check after another week. I hadn't read about the 1.020 curse - good to know.

 

[NavySur4]

I decided to leave this alone and keg after 4-5 weeks to see if anything changed. It's been at about 68-70 degrees for the last 10 days and this morning while getting ready for work, I hear a lot of bubbles. I take off the towel and notice the lid is bulging again and there is a lot of CO2 in the bucket again. I checked the gravity this weekend and it was 1.018 so I'm thinking it may actually finish out. I still plan on leaving it for another couple of weeks (5 or 6 total in fermentor) and checking again.

 

[sgillespie]

I understand Scottish Yeasts tend to drop out before its finished. I've had a similar problem with white labs' scottish.

 

[Skarekrough]

Did a Scotch Ale that performed about the same. It was fermenting in my basement and it did great for awhile and then just stopped at 1.020. It was decent, but just didn't have the taste I usually associate with a Scotch Ale.

Hauled it upstairs and slapped a brew belt onto it. A day later I re-pitched with the same yeast and it dropped down to 1.012 in a few days. It started to taste more along the lines of what I expect a Scotch Ale to taste like as well.

At 1.020 it's probably fine. I decided to go the route I did because it didn't taste quite right. Had it tasted fine I would have kegged it and drank it.

Brewing isn't always about the numbers and the math. It can help but it's no substitute for the brewers own preferences. And that can actually be where you find and make some fantastic discoveries as you start formulating your own brews.

 

[HexKrak]

10% crystal seems like quite a bit to expect such a low FG. Even with a dead on mash do you really think it'll could get down to 1.012? I'm wondering if the unfermentables in the crystal might just have it finishing at 1.020.

 

[NavySur4]

Update - after sitting at 1.020 for about 10 days, it seemed to pick up fermentation again the past two days. I checked last night and it was sitting at 1.012. Weird how it started, took a few weeks vacation, then came back to work and finished. Now I'll wait a couple more weeks for it to clear up. Yeast truly do work on their own schedule.