Stuck Fermentation?

[Aristotle]

I know there are lots of existing threads on stuck fermentations, but I couldn't find one that seems to fit my specific circumstances. My problem is this:

I'm brewing an East Coast style IPA, with OG 1053, using Omega DIPA yeast. I made a 2-step starter to make absolutely sure I had enough yeast, and pitched it into the wort which I had aerated for 30 mins with a pump and an air filter. I also used a servomyces tab in the boil. I've got it in my brew fridge set at 18 degrees.

Fermentation took off after 6 hours and was going vigorously. After just 48 hours SG was down to 1022.

But then everything seemed to stop. The krausen completely disappeared from the surface of the beer, and there is zero activity in the airlock. Now, after 96 hours in total, the SG is at 1020 and looks like it's going nowhere.

Can anyone offer any possible explanation of this? I was expecting an FG of 1012 or lower.

I know that 96 hours is not a great deal of time, and things could change, but the way that it took off so fast and then seemed to stop completely has got me worried...

 

[simon12]

I would just give it another 48 hours before you worry.

 

[MrN]

Have you got temperature control? Were there any significant changes in temperature while fermenting?

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[Aristotle]

Yeah, I've got temp control. It's been between 17.5 and 18.5 throughout.

 

[MrN]

How long has it been since you measured it at 1.020? Might just be a slower ferment, particularly if it's at a slightly lower temp. Could always try giving it a swirl?

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[Aristotle]

I thought that too. But the way it fermented so quickly to begin with seems to suggest otherwise.

I've given it a swirl and cranked the temp up a couple of degrees. I'll see how it goes.

 

[Mungri]

I thought that too. But the way it fermented so quickly to begin with seems to suggest otherwise.

I've given it a swirl and cranked the temp up a couple of degrees. I'll see how it goes.

The first few days are the most active. That's normal. give it another couple of days and see if it's still going down before you start messing about with it.

 

[MrN]

I had a hefeweizen ferment at 17c and it seemed very active at first but after about 4 days was only down to 1.016. I increased the temp and gave a small swirl and it did end up finishing bang on my target fg.

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[Clint]

My stuck JB ipa responded to a swirl and increasing the temp a bit...and bunging in 200g of sugar! It took around 5 weeks to get anywhere near. It's been in a keg for a couple of months and has turned out fine. Reasons unknown but I'd change the yeast next time...

 

[JapanBrew]

I would say not to touch it for at least 10 days. Lots of things happen during that time and you'll probably loose those points during that time. But you have to remember there are a ton of factors that determine if your brew will go down to your projected gravity. Even 2 degrees difference in mashing will change the outcome of the beer. It's understanding what type of sugars you've created during your mash.

 

[Sandimas]

Yeah, I've got temp control. It's been between 17.5 and 18.5 throughout.

Think that may have been a bit on the low side. Not familiar with that yeast, but just looked it up and the temperature spec for that yeast says a minimum of 65F which is 18.3C.

I've had stuck brews before when the temp dips below 18C and always go for 19C to stay on the safe side. I also seem to get stuck brews when there's a particularly vigorous early ferment, almost like it runs out of steam - long and slow seems to be better.

Get the temp up a bit (21C or so) and give it a stir, will hopefully get it going again.

 

[terrym]

Get the temp up a bit (21C or so) and give it a stir, will hopefully get it going again.

That's exactly what I'd do :thumb:

 

[Aristotle]

Thanks for all the replies.

I turned the temp up to 20 yesterday, and already this morning there's some signs of activity. Looks like it's back on track! I think maybe I had it a little too cool for this yeast strain.