Stuck Fermentation ?

[Superoo]

Howdy All,

I have a brew going which I think may have stopped fermenting early.

Some info...
Its an all grain stout, BIAB and no chilled for only 5 days.
All hops are flowers.
OG was 1.050.
Expected FG is 1.014.
Yeast was an October 11 packed Wyeast 1272 smack pack, which swelled fine.
Yeast was pitched at 19 degrees, and then dropped the temp the following day to 16.5.
I dry hopped 20g cascade flowers into the no chill cube.

There is nothing different I've done with this brew than any others, and I've done this receipe once before and all was fine, in fact its bloody delicious (google BN Army CYBI Rogue Shakespeare Stout).

The SG after 9 days, is 1.020 and its still stuck there.

3 days ago I pitched a pack of us05, and put the temp back up to 20, just to try something, but the krausen hasnt really fired up, and it still appears stuck.

Now - the honesty comes out...
I forgot to oxygenate the wort when I poured into the fermenter, and I am wondering if this might be the cause.
I usually only make light beers so oxygenation not seeming to be quite as important, as they all brew out fine.

My question is...
Should I give it a good flogging and oxygenate the wort, or will it damage my brew now that its 2/3 the way thru fermentation ?
(Its a fairly expensive recipe so I want to save it as best I can).

Or what other suggestions are there that might help get the SG down ?.

I cant think of anything to do here, so any ideas would be gratefully appreciated...

 

[drsmurto]

Rename it a sweet stout and you'll be fine. :icon_cheers:

If rehydrated US05 did nothing (assuming you rehydrated) then i suspect you are stuck with that FG.

What was your mash temp and grist?

EDIT - don't aerate it at this stage, you'll (probably) oxidise the beer.

 

[benno1973]

Howdy All,

I have a brew going which I think may have stopped fermenting early.

A few questions...

1. Did you try swirling the fermenter around a bit to put the yeast back into suspension?
2. Did you rehydrate the US-05 before pitching it?
3. What temp did you mash it at? And have you calibrated your thermometer to know that this is correct?
4. Was the recipe exactly the same as the previous version that you did?
5. Did you make a starter for the 1272?
6. Are you assuming that the US-05 isn't doing anything based on krausen, or have you measured the SG?

 

[Superoo]

A few questions...

1. Did you try swirling the fermenter around a bit to put the yeast back into suspension?
2. Did you rehydrate the US-05 before pitching it?
3. What temp did you mash it at? And have you calibrated your thermometer to know that this is correct?
4. Was the recipe exactly the same as the previous version that you did?
5. Did you make a starter for the 1272?
6. Are you assuming that the US-05 isn't doing anything based on krausen, or have you measured the SG?

Cheers Doc and Kaizer...

Mash temp was 66, varied 65 to 66.5 throughout the mash.
recipe basics...
3.88 Kg Maris otter.
0.65 kg Choc Malt.
0.65 kg crystal.
0.59 kg rolled oats.
88 grams roasted barley.

80g cascade flwrs 60 mins
30g cascade into cube 0 mins

realising how lazy i've been now i have to stand before you and answer these questions....

- Didnt try swirling the fermenter
- Didnt rehydraye the us05
- Mashed at 66, temp is accurate, I have about 3 thermometers, and all conform to my controller.
- Recipe exactly the same, but the chocolate malt was much darker than from previous supplier.
- Didnt make a starter
- Measured sg, and theres no real krausen action.

Thanks for taking the time to ask those questions, I need to up my standards a bit i think...

 

[benno1973]

So mash temp isn't an issue, and given the grain bill, I don't think that's the issue.

I would say it's likely to do with yeast health. MrMalty calculates 213b yeast cells required, while a smack pack at 100% viability has 100b cells, give or take. Making a starter would have upped the cell count. Additionally, not rehydrating the US-05 and pitching onto an already partly fermented wort, you would have lost a large part of the viability of the US-05.

Given that this beer *should* ferment further, you can try swirling the fermenter for a bit to rouse some of that yeast into suspension. Keep the temp around 20C and see what happens. You can always rehydrate another pack of US-05 and add that back? Or, as mentioned, keg it and call it a sweet stout!

 

[benno1973]

Thanks for taking the time to ask those questions, I need to up my standards a bit i think...

Not at all! We all take shortcuts at some point. It just depends if those shortcuts have undesired results!

 

[felten]

If you're going to repitch you have to get the yeast active and in the fermenting phase before you pitch it, but that might not even do anything if your beer has gone as far as it can.


You could always throw some wild yeast/bacteria in there if it's way too sweet

 

[Superoo]

cheers to all for replies,

will try gently rousing the yeast and upping the temp to 20 for a week.

otherwise, yes, it will be a sweet fartmaker that will still probably taste nice...

must get into making starters i guess...

 

[ekul]

Are you using a refractometer to measure the fg? Once there's alcohol in the mix the reading needs to be adjusted