Overpitching And Fg

[dreadhead]

G'day everyone, just a quick question, can the overpitching of yeast have any impact on stuck fermentation?

Currently have two 9L batches (an Alt and a English Brown) on the go, and both seemed to have stalled at 1.020 after 10 days in the primary. I have tried to give them a bit of a swirl to resuspend the yeast but this hasn't had any affect, same gravity reading for 3 days straight an no activity in the airlock.
Both batches are made from DME/Specialty grain fermented at 20 deg, pitched a whole dried pack of K-97 for the Alt and pack of Nottingham for the English Brown. The fermentation took off like a rocket for the first couple of days, and all activity stopped.

Gravities seem a bit too high, so don't want to bottle as yet. Should I just wait it out and hope for a miracle or maybe repitch a neutral flavoured yeast to clean up the residual sugar?

Cheers

 

[Cortez The Killer]

I don't think that a whole pack of yeast in a 9 litre batch is over pitching

DME can be give higher FG

What was the OG for both batches?

I'd let it sit for a while longer and see what happens

You could pitch 1/2 a pack of US-05 in each and see if that restarts it - but I'd hold on for a while longer - perhaps even lift temps to 21-22*C to complete

Cheers

 

[brendo]

1020 does seem a tad high - what were the OG's for them?

I wouldn't think that overpitching would cause a stall... should be OK.

A couple of things you can try - give it a bit of a swirl and bring the temp up a degree or two to try and spur it along, or if you have another fermentor, rack it to secondary to see if you can spur it along.

Cheers,

Brendo

 

[goomboogo]

What was the amount of dry extract and specialty grains(what types) used in these beers? The percentage of specialties will have an effect on finishing gravity as well. The yeast quantity pitched in your two beers of 9 litres is not likely to be the culprit.

 

[flattop]

You could consider racking but swirling up the yeast cake first so extra yeast gets into the secondary. Then again you could sterilize a stirrer and just stir up the cake on the primary.
I would think that it is still fermenting and the yeast has just slowed down.... 10 days, you could afford to wait a few more after more agitation.

If you bottle then bottle in Pet

Consider re-hydration techniques, i had a couple of dodgy pitches with dry yeast and now I either re-hydrate or make starters for each batch.

 

[dreadhead]

Thanks for the replies.

I didn't have a hydrometer at the time before pitching (had to borrow from a mate, and got impatient), but Beersmith predicted the OG of both around the 1.052 mark. But that probably isn't the most accurate figure u can get.

As for the approx grain bills:

Alt: 72% LDME, 18% Caraamber, 9% Caramunich I and 0.6% Black malt

English Brown: 82% LDME, 8% caraamber, 7% Pale Choc and 3.5% Caramunich I

Both beers smell and taste fine, maybe a little sweet, but that may be because I didn't hop as much as I usually would.
Plan to rack the Alt off the yeast cake anyway and CC for a few weeks, so will leave at room temp for a couple of days before putting it in the fridge, see if that will finish things off.

Cheers

 

[reviled]

Theres a fair bit of unfermentables in the Alt which could explain the high FG...

 

[muckanic]

Broken record time. Try some nutrient. It can be deficient, even in all-grain brews. Stalling at about 60% attenuation after a strong start is unacceptable, and is almost certainly neither a dextrin nor a yeast problem.