Stalled IPA

[mtb]

I put down a double batch of Zombie Dust on the 20th. 22L into each kegmenter, pitched a smacked & inflated pack of Denny's Favorite 50 into each. Oxygenated for 1min and set to 18C. All my usual practice.
One difference in this batch was the dry hop addition; I added it two days into fermentation, at high krausen. 90g Citra pellets into each kegmenter (in a hop bomb).

Fermentation has been generally sluggish but now it appears to be stalled @ 1.03. I have pitched 10mL of harvested American Ale yeast and added 1mL of phosphoric acid since a pH reading indicates 4.8, assuming this is due to the slow ferment since quick and healthy fermentation lowers pH more effectively.

Anything else I should check for? Could that large dry hop have affected the yeast at all? It tastes/smells great, the recipe indicates an FG of 1.02, high but that's what I'm aiming for. Mash temp was 69C.

 

[MitchD]

Sounds like a massive under pitch into each fv. The repitch was also under size considering the absence of oxygen and the presence of alcohol.

I'd bump the temp up to 20c+ and give the fv a good swirl each day for a couple of days until either the gravity drops or you decide its done.

 

[mtb]

Yeah, I figured underpitch.. you don't think 10mL is enough? I only need to attenuate another 10 points (1.03 to 1.02)
Granted if there is no ill effect from pitching even more yeast, I definitely will. Another 15mL into each kegmenter today.

 

[MitchD]

I'd go for like 100ml if you are talking about harvested slurry. Check Mr malty, it'll come up as about the same as a packet of dried. But really you have enough in there, it's just worked too hard and finished early.

What does it taste like?

 

[mtb]

With an OG of 1.07 I really should've done a starter or pitched extra yeast actually. I agree with you that this was an underpitch.
It smells and tastes great but there is a huge Citra dry hop in there, so any off flavours are masked at this point. I've just pitched 100mL harvested slurry (although quite thick with yeast) into each to get this bad boy fermented out. I did a Kolsch the day after and it hit FG two days ago, now it's waiting on the IPA..

 

[Schikitar]

I learnt my under-pitching lesson with a RIS that I did, never again! Good luck, hope it comes good!