Stuck Fermentation


Barley Legal Member
I am brewing an experimental beer and very underwhelmed with the progress. I was challenged to make a Cheesecake inspired beer. I started with 2 row and added some biscuit and wheat malts. Beer Smith put my starting gravity at 1.075, which I missed by about 15 or so points. I was able to compensate with some boiled DME and pitched some Sour Batch Kids yeast from Imperial. It bubbled for over a week, but when I checked the gravity again, sad face.
I am stuck at 1.030. The taste is sweet on the front end with a tangy after taste. Is it possible that the IBUs are too high(30) for it to finish? I know I can't take any hops out, but my idea would be to brew the same recipe again without the hops. Then blend the two and re rack.
Any thoughts?


Active Member
SO my original thought was maybe your pH was too low. But then I went to the Imperial website,

"An exclusive blend containing a low attenuating Belgian saison yeast, Lactobacillus, and three Brettanomyces yeast strains. This blend is great for emulating lambics, Flanders reds, sour farmhouse ales and any other brew you would like to funk up. Keep you IBU's low to allow the lacto to work.
This blend contains a strain that tests positive for the STA1 gene via PCR analysis and is therefore considered to be Saccharomyces cerevisiae var. diastaticus."

So maybe the IBUs were a little high. It also just might need more time. How big of a batch did you do? If you have some to spare, you could consider taking a small amount out, make a starter of say S05 and see if that small sample will ferment out any more. If it does, you might be able to pitch a very healthy starter and see if it will drop more. If it does not, then you might just be done with that batch.
I think the low attenuating Belgian yeast might the culprit here, but that's just my thought.

Matt Talbot

My guess is the IBUs are not the culprit. 30 isn't all that high.
What did Beer Smith predict your FG should be?

That yeast has 80% attenuation which is pretty high, so that shouldn't be the issue, unless it was under-pitched.
That could be the case, 1.075 is a pretty high OG.

What was your mash temp?
Higher mash temp could result in higher FG because of the unfermentable sugars produced.

You could try adding more yeast (per James suggestion), or throwing in some Amylo 300 enzyme to bring the gravity down a bit.

But you do have a 6% beer there, as it is. Does it taste good?


Barley Legal Member
I agree with both Matt and James. If you only pitched a smack pack into a 1070 wort, you. Probably significantly underpitched for such a big beer. It may drop out over time, but could be a very slow development over the next few months. Diastaticus and Brett will eventually chew through almost every sugar available given time.
If I were you, and I wanted to drop the bulk of the last few points quickly, I would preferably take some fresh yeast from a commercial brewery who has clean beers (or like James said, a packet of S05) and make a 1L starter. Once fermentation subsides, add 1 Liter of your unfinished beer to the starter. This will help the yeast to acclimate to whatever acid may be in your beer preventing terminal acid shock. Once it restarts fermenting, pitch whole starter to your fermenter.
Good luck!


Barley Legal Member
Beer Smith claims the OG was going to be 1075. My mash temp was 155ish same with sparge water. When I cooled and took the reading, it came out as 1050. I added some DME to bring it up to about 1065.
Imperial Yeast boasts 200 billion cells per pack. More than enough to handle the beer. However, I took my time getting the yeast home after buying it. I now fear that I inadvertently under pitched due to killing the cells days earlier. I will try to repitch first, then take the rebrew-with-no-hops approach. Essentially halving the IBU's and taking a risk on a ten gallon batch.
What are the odds that the cherries in secondary will also cause a problem? I'm going with maraschino sanitized in Vodka.


Gloucester County Chapter Lead
What about pitching some French saison yeast into it? It's usually a monster attenuator. Belgian saison yeasts are notorious for a the 1.030 stall. Every time we've used on (granted not the sour batch kids pitch) we've had to bump the temps to 80 or higher to get them to continue on.

Not sure what else is in that pitch to recommend the temp bump.. But I do know Belgian saison yeasts are known for stalling


Barley Legal Member
I moved the fermenter to a cooler place and it started to bubble again. When I took a reading yesterday, it only moved 2 points. I added the cherry concoction to see what happens next. I see no reason to brew a new batch with no hops, just to hope it works. Another yeast strain is also on my list of things to try. I like the French Saison suggestion. I am also looking at Imperial's Suburban Brett strain. It has a cherry taste anyway without the IBU restriction. It says it's good for aging.