IPA stuck at 1.020, to repitch or go with it?

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darkthrone

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Hey all!
So as the title says, my IPA's fermentation seems to have plateaued out at 1.020 for the past couple of days and I'm wondering if I should repitch some more rehydrated yeast or just go with it and start dry hopping?

My OG was 1.068 so It's still going to have plenty of punch around the 6.3% ABV mark but the recipe had the final gravity at 1.011 which puts me pretty far from the mark.

I have been reading up and it seems it could be a problem with my mash temperatures leaving too much unfermentables in my wort.
I also had some temperature drops during fermentation due to my heating system crapping out on me so that's another possibility.
I've tried stirring the wort gently to rouse the yeast but it hasn't had much effect.

So to pitch some more yeasties or not? The wort is smelling and tasting pretty amazing so far so I'm worried I may create some off-flavours or lose body by pitching another pack of yeast. Any advice would be much appreciated! :)

Cheers!
 

shacked

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Hey mate,

You are about 69% attenuated which might seem a little low but there are a lot of variables:

What temp did you mash at?
What yeast did you use?
How much did you pitch?
Did you make a starter or rehydrate dry?
Did you use a lot of crystal malts?
What was your fermentation temp?

Also, your target of 1.011 (83% attenuation) might be possible with a low mash temp and maybe some simple sugar; plus a good attenuating yeast (like 001/1056 for example).
 

darkthrone

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shacked said:
Hey mate,

You are about 69% attenuated which might seem a little low but there are a lot of variables:

What temp did you mash at?
What yeast did you use?
How much did you pitch?
Did you make a starter or rehydrate dry?
Did you use a lot of crystal malts?
What was your fermentation temp?

Also, your target of 1.011 (83% attenuation) might be possible with a low mash temp and maybe some simple sugar; plus a good attenuating yeast (like 001/1056 for example).
Thanks for the reply mate!

My mash temp was around the 67-68 mark after the grains hit the strike water. dropped to about 65 over the hour.
I used two packets of the Liberty Bell yeast (dry) from the mangrove jacks craft series. I rehydrated them in 200ml of sanitised water and pitched it into the wort at about 23 degrees.

About 280g of crystal malt in the mash.

Fermentation temp actually went up a bit as the yeast was going mental, so maybe topped at about 25 but then dropped back down to being quite cold at one stage (maybe 15-16 degrees) due to my heat belt crapping out over night. I have it steadily warmed to 22-23 degrees now and have tried rousting the yeast but its still stuck on 1.020!
 

RdeVjun

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Hydrometer or refractometer used to measure SG?
 

darkthrone

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RdeVjun said:
Hydrometer or refractometer used to measure SG?
Currently only have a hydrometer, but I have made sure it reads true in water, and always check wort temperature before measuring gravity.
 

RdeVjun

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Ok, good, evidently you're all over it.
If it was a refractometer the value would need to be corrected for alcohol. It's an outside chance but worth asking to be quite sure.
 

darkthrone

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RdeVjun said:
Ok, good, evidently you're all over it.
If it was a refractometer the value would need to be corrected for alcohol. It's an outside chance but worth asking to be quite sure.
Totally mate! Any help is appreciated haha.
 

eldertaco

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If you've got some spare yeast (even bread yeast will do), you could try fast ferment test to see if there's any fermentables left in there?
 

darkthrone

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eldertaco said:
If you've got some spare yeast (even bread yeast will do), you could try fast ferment test to see if there's any fermentables left in there?
I was actually going to suggest this at the start.

What if I siphone out some of my wort into a sanitised pyrex container or something and drop some yeast in it, then see if the SG drops in that?
Or I guess see if the yeast start some activity?
 

mtb

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Give it a few more days at 21 I reckon. The temp has fluctuated a fair bit which would be a little shocking for the yeast, give them time to readjust
 

wereprawn

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A combination of highish mash temperature , a highish gravity and a yeast that's not more attenuative would be the issue . I'd expect a fg around that .
 

TheWiggman

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^ agree. I'd say you've hit the FG. You've done the simple things like rouse gently and bump temp so there's little else you can do. Combination of high mash temp and high OG = highish FG. I'd also check your thermometer if you havent already to make sure it's in the ball park.
 

darkthrone

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Thanks for the replies so far!
So mash temp was highish?

The recipe called for 66-67 degree water which I thought I was pretty spot on or have I missed something?
 

eldertaco

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Yeah I'd say it's probably at FG too, but if you're keen and you can be bothered there's always the fast ferment to make sure.
 

darkthrone

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How much would a 3rd packet of yeast affect the final flavours and such? Or is that a "how long is a piece of string" sort of question? haha
 

mosto

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Either or IMO. I've recently finished a keg of an IPA I brewed. It stuck at 1.020 as well and was supposed to get down to around 1.012. However, I know in my case it was under pitching that caused the issue. I re-pitched some US05 slurry that I had estimated would not have enough cells but didn't have anything else suitable on hand. I thought about pitching more yeast when it stalled as I'd restocked by then, but didn't for whatever reason. Instead, I gave it an extra week to a) see if it came down by itself b) let any off flavours from the under pitch subside. It came out very nice and I actually enjoyed the extra body it had. So while my pitching practices were not ideal it turned out ok on this particular occasion. There may well have been some unwanted flavours in there somewhere, but being a hoppy IPA, they were well and truly masked over to my palate.
 

manticle

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Before you go any further - kegging or bottling?

If bottling, definitely do a fast ferment test to check.

I'm not convinced 67-8 with just over 250g crystal will result in 1020.

Water at 67 might give a mash temp around 62, depending on liquor to grain ratio and a bunch of things. Calculate strike water to give desired mash temp. Every system is different.

Even if kegging I'd be inclined to run the ff test but if bottling, we're not at home to Mr Cockup.
 

darkthrone

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manticle said:
Before you go any further - kegging or bottling?

If bottling, definitely do a fast ferment test to check.

I'm not convinced 67-8 with just over 250g crystal will result in 1020.

Water at 67 might give a mash temp around 62, depending on liquor to grain ratio and a bunch of things. Calculate strike water to give desired mash temp. Every system is different.

Even if kegging I'd be inclined to run the ff test but if bottling, we're not at home to Mr Cockup.
I used 72 strike water as the recipe suggested, then checked the temp once all the grain was mashed in and it was at around 67-68 when i closed the lid and wrapped the urn up
 

manticle

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Ok. You said the recipe called for 67 water. Maybe a typo?
 

darkthrone

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manticle said:
Ok. You said the recipe called for 67 water. Maybe a typo?
Sorry was typing in a hurry this arvo!

I meant mash temp 67-68, strike water 72

And I'll be bottling to answer your other question :)
 
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