I’m making a Spencer Abby clone from yeast I harvested from the bottle. The yeast harvesting went well and the fermentation started fast, there was a thick krausen in 24 hours. My temp control wasn’t good. ( I am definitely making a ferm chamber!) I was planning on fermenting at 72 then bringing it to 78 when krausen went down until it got close to target gravity and stayed there then two weeks at 50., all per the recipe. I have rooms with different temps in the house which is how I currently control temp: kitchen 68-70, back room 75-85 if I want, cellar floor 60 ish right now, root cellar 50 ish. After the 2nd day it got into upper 70 's so I left windows open to bring it down but it went way down to 60. I wrapped it in a blanket and closed the window and it got back up to low seventies and I was able to keep it there. The krausen lasted a couple days and I put it in the back room and got it to the upper seventies where its stayed for two weeks. It hasn’t budged from 1.020 for two weeks and the target gravity is 1.010. I’m worried both that it won’t be as dry as I want it and that upon bottling the yeast will wake up and I’ll have gushers. I’m wondering what if anything went wrong. Is it just this yeast acting differently than the trappist ale yeast called for (3787 or WL530) or the crash down to 60. I’m thinking I’ll follow the recipe and bring the temp down for awhile then bottle. The OG was 1.058 measured with a hydrometer at 65 degrees ( pitching temp). I hit all my mash temp targets. The 1.020 reading was taken several times with a hydrometer at 78-80.
The drop to 60° wouldn’t be the end of the world. This yeast may be finicky. You can try to warm it up and rouse the yeast. What I would do is pitch a small active starter of 001 or 1056.
Was this all grain or extract? Mash temp and length?
I re-read and see that it is all grain. What was the mash temp?
Tapatalk is not allowing me to edit still
148 for 75 min, 162 for 15 min, mash out 168.
It should finish well lower than 1.020. I would pitch fresh neutral yeast
I suspect that the harvested yeast may have had a problem. Try repitching, but be aware that it takes a lot of yeast to do that. Something like a qt. of slurry wouldn’t be too much.
Be aware that some of the trappist breweries reportedly bottle condition with different yeast than what they primary ferment with to maintain their proprietary strain. Just something to keep in mind if your clone does not live up to the original.
While this particular brewery night, according to BLAM almost no Belgian breweries do.
I’m picking up similar esters to the original, I don’t think its a bottling strain. Denny, Steve is recommending pitching a neutral yeast, are you recommending that in a larger amount? Also, the drop from 1.020 to hopefully 1.010 will take care of potential oxidation from pitching more yeast? I’ve never needed to do that but I assume I need to aerate again. If I’m aerating anyway is it possible to get to the yeast at the bottom and make a starter from that?
I’ve had good luck with non-stirred 1 quart starters in active fermentation. Adding dry yeast or a liquid culture without a starter might not to well.
Steve,
A starter of what kind of yeast? If you recomend a neutral yeast what do you mean by that?
001 or 1056. I would avoid dry yeast in this case. A big slurry as Denny mentioned would work as well.
I’ll have to let go of my intention of harvesting the original yeast for later experiments. I will have to wait a few more days before I can get to my lhbs. Any problems with that?
Do what you can. Just be careful bottling too early, It may be as low as it will go, but with an untested yeast, it is hard to say.
I don’t think it matters a lot what strain you pitch. At this point, though, you don’t want to re-aerate the beer, so you need to pitch enough yeast to not need cell growth.
Thanks for the advice Steve and Denny. I’ll make a starter after work from some yeast I have at home.
A BIG starter. Not just a qt. starter. Maybe a gal. or two. Or is there a brewpub nearby where you could get slurry?
Sadly, very sadly, there is no nearby brewery. 
I’m glad you re-emphasized the starter size as I was thinking two quarts. I also like that you refer to quarts and gallons, not this liter nonsense. 
I’ll make a big starter. With a starter that big would you decant as much as possible so I’m not adding a gallon of liquid to 5 gallons of beer?
I disagree Denny. I have had good luck with 1 quart/liter (I say liter because that is how the flask is marked), not stirred, and pitched at high krausen.
Well, that’s good to know, Steve, although I haven’t been that lucky.
Pete, AFAIAC you should ALWAYS decant you starters.