Stalled fermentation

[bmham]

Hello. Relatively new homebrewer here that has just started using an electric system.

Brewed a hazy IPA the other day. Mashed in at what my controller said was 154 degrees, but shortly after mashing in, realized that the actual temperature was 168. The mash was at this temp for about 10 mins, maybe 15, before I realized the discrepancy and was able to cool it down into the 150s.

Predicted OG was 1.046 and actual OG was 1.043 so I thought I was OK.

Pitched omega's tropical IPA liquid yeast at about 75 deg (manufacturer states best temperature range is 70-85deg). I pitched around 4pm. By the following morning, gravity was 1.028. However, airlock activity completely stopped at that point, and 2 days later, I'm still stuck at 1.028 with no activity.

Does anyone have any insight as to why I'm stalled in fermentation? Is it because of the high mash temp initially that I ended up with a lot of unfermentable sugars?

What can I do?

Thanks in advance!

 

[IslandLizard]

How are you measuring your gravity, with a hydrometer or refractometer?

If it's with a refractometer you'll need to apply a correction formula due to the alcohol being present in your sample will badly skew your refractometer reading. For example this one, use Part II:
https://www.brewersfriend.com/refractometer-calculator/
There are others...

 

[bmham]

How are you measuring your gravity, with a hydrometer or refractometer?

hydrometer

 

[IslandLizard]

hydrometer

OK, the gravity should be a pretty much a direct read.

Most fermentations take much longer than 18 hours to complete, many may not even show much activity until after a day, or 2.

It could be due to the initial high mash temp, yes, denaturing much of the beta-amylase. That would leave lots of dextrins that couldn't be broken down in the mash. Now 10-20 minutes above 160F (@168F) should not cause that much damage, but maybe it did.

I'd let it be for a week and check again. And stop opening that fermenter.

BTW, is this a recipe kit? An OG of 1.046 is a little low for an IPA.
Link?

 

[bmham]

Thanks for the reply. Not a kit- recipe I’d found online that author had OG 1.065 and when I put into Brewfather gave OG 1.046.

I have a tilt in the fermenter so I haven’t had to open it. Wondered if the tilt had malfunctioned but there’s been zero airlock activity for over 2 days after dropping from 1.043 to 1.028 in the first twelve hours.

 

[IslandLizard]

From Omega Yeast:

OYL-200

TROPICAL IPA​

A unique Saccharomyces strain that produces delicate, tart, tropical mango and pineapple fruit characteristics with a clean finish. Try higher fermentation temperatures to really bring out the tropical aspects. It’s stubbornly non-flocculent, but the results are worth the trouble.
This strain tests positive for the STA1 gene, an indicator of Saccharomyces cerevisiae var. diastaticus, and is capable of fermenting dextrins, resulting in very high attenuation.

She's a diastatic yeast, so she should be able to break down dextrins. But it takes time...

Is the beer still very cloudy? If so, that's a good sign, the yeast is still suspended.

Are you using some form of temp control, to keep the fermentation temps steady? That's important.
I'd give it at least 2 weeks at 70-80F, you could even slowly ramp it up to keep her engaged. Just make sure the temp doesn't drop as that could cause her to flocc out prematurely.

It's possible your Tilt is not giving you the right info, for whatever reason. But don't open the fermenter, air (oxygen) is the nemesis with those styles of beer.

BTW, what kind of fermenter are you using?

 

[bmham]

From Omega Yeast:

She's a diastatic yeast, so she should be able to break down dextrins. But it takes time...

Is the beer still very cloudy? If so, that's a good sign, the yeast is still suspended.

Are you using some form of temp control, to keep the fermentation temps steady? That's important.
I'd give it at least 2 weeks at 70-80F, you could even slowly ramp it up to keep her engaged. Just make sure the temp doesn't drop as that could cause her to flocc out prematurely.

It's possible your Tilt is not giving you the right info, for whatever reason. But don't open the fermenter, air (oxygen) is the nemesis with those styles of beer.

BTW, what kind of fermenter are you using?

I haven’t opened the fermenter to assess clarity.

I am using a fridge as a fermentation chamber with an inkbird for temp control. I started at 74 and slowly increased as high as 78 then have since backed off to 75 (like i said manufacturer recommended 70-85).

This is only my 5th batch and first
Time not using Kveik- so obviously used to rapid fermentation. But I thought it was strange that I’d drop from 1.043 to 1.028 in 12 hours then no airlock activity or drop in SG for the next 2.5 days.

Thx

 

[IslandLizard]

I thought it was strange that I’d drop from 1.043 to 1.028 in 12 hours then no airlock activity or drop in SG for the next 2.5 days.

Yes, that's strange.
The lack of bubbles not always means there's lack of fermentation. Fermenters can leak headspace gas. Many fermentations have completed successfully, without ever showing a bubble in the airlock.

Since you can't see inside your fermenter, you don't know how the Tilt is positioned. It could be lying sideways in thick krausen.

Since you had good airlock activity, your yeast is/was obviously working. That's an important notion, your beer won't spoil by lack of intended fermentation. Most beer benefits from conditioning, so even after 3 days that beer is not done yet. Let her be.

Just give her time, the yeast knows what to do, and try to disregard the reported gravity from your Tilt.

 

[bmham]

O

Yes, that's strange.
The lack of bubbles not always means there's lack of fermentation. Fermenters can leak headspace gas. Many fermentations have completed successfully, without ever showing a bubble in the airlock.

Since you can't see inside your fermenter, you don't know how the Tilt is positioned. It could be lying sideways in thick krausen.

Since you had good airlock activity, your yeast is/was obviously working. That's an important notion, your beer won't spoil by lack of intended fermentation. Most beer benefits from conditioning, so even after 3 days that beer is not done yet. Let her be.

Just give her time, the yeast knows what to do, and try to disregard the reported gravity from your Tilt.

Ok, great- thanks for the advice!!

 

[BrewZer]

Something I recently started doing is a starch test using iodine on my mash. I check it at 15-minute intervals, and I can keep track on how fast conversion is proceeding.

If I overshoot my strike temperature, I've noticed my conversion isn't as complete, and I get a smaller beer as a result.

 

[ItsReck1]

I have used Omegas hazy yeasts. They typically end on the higher end. Albeit this higher than I have experienced. Im sure the act of you mashing at 168 and cooling down likely made plenty of long chain sugars that was hard for the yeast to break down. You can always rouse the yeast see if it will eat anything left. Taste to see if it is too sweet for you. I think the high temps though made a lot of long chain sugars that the yeast couldn't power through. But taste it first see if you like it before doing anything to the beer at that point.