How best to handle ale fermentation when it slows?

[Fore]

I'm finding that a few of my ale kits seem to stop at about the 1.017ish region. I have well aerated, pitched at good temp and fermented almost stable in the region of 18 degrees. It's not the dreaded 1.020 stick, because if I turn the temp up to 22 degrees, the bubbles get going again, if very slowly (fermenter is well sealed, so bubbles are a good indicator of activity). In the latest case, a week at 22 degrees and it has moved from 1.017 to 1.014.

So it's not a disaster, as it's still heading in the right direction, but I have 2 concerns, i) that by turning the temp up to 22 I might be changing the flavour, and ii) it's sitting on the yeast trub a long time (already 16 days in the current case).

My plan is to transfer to secondary in a few days and keep at 22 degrees until all activity ceases, then cool for clearing. At least that way I get it off the majority of the yeast trub. Is this a good plan and do I have anything to worry about? Is turning up to 22 for the last few ABVs actually a good thing, even if it's for an extended period (I think I read somewhere that others do this)? I just wonder what best practice is.

 

[Cussword]

I would give it a stir :thumb:

 

[Maysie]

I had this on my last batch, (Woodfordes Nog). It stuck at 1015 and would not go lower.
I just bottled it in the end, but now think I should have made more of an effort to revive it for the final part.

When people speak about stirring the brew, do they mean gently break up/mix in all of the trub as well, or just stir the liquid on the top??

 

[phettebs]

Turning up the temp at the end of fermentation to help it finish isn't going to affect flavour. Now, if you do it within the first 3 days of pitching then you might have some concerns. I frequently move my FVs to a warmer area of the house at the end of fermentation during the winter just to make sure it finishes.

Giving a gentle stir is also just fine.

 

[rpt]

Off flavours from high fermentation temperature only happen in the first few days. Raising the temperature after this to get full attenuation is good practice. I raise it 1C every 12 hours until it gets to 24C.

 

[Cussword]

When people speak about stirring the brew, do they mean gently break up/mix in all of the trub as well, or just stir the liquid on the top??

Give the lot a good rousing, it will do no harm :thumb:

 

[Fore]

Fantastic, this is exactly what I wanted to know. So the flavour is only affected in those early fast days; no problem then, and if 24 degrees is OK, even better. Probably will reserve stirring as a last resort, as temperature seems to do the trick.

Next time I see this I'll be raising the temperature immediately then, so won't have the worry of it sitting on the trub too long. Thank you. :

 

[gl0ckage]

Stir it, or rack it and it should restart, I have topped up many a brew with sugar and water and it doesn't start fermenting it until I rack it.

 

[rpt]

When people speak about stirring the brew, do they mean gently break up/mix in all of the trub as well, or just stir the liquid on the top??

Give the lot a good rousing, it will do no harm :thumb:

But be careful not to splash. You do not want to oxidise the beer.

 

[Maysie]

When people speak about stirring the brew, do they mean gently break up/mix in all of the trub as well, or just stir the liquid on the top??

Give the lot a good rousing, it will do no harm :thumb:

But be careful not to splash. You do not want to oxidise the beer.

So more of a 'gentle stir' than a full-blast with a paddle mixer on the end of a drill then...! :thumb:

 

[Sandimas]

Does stirring really work? Seen it mentioned on here many times, and done it myself many times with stuck brews, and frankly it hasn't made any difference. Higher temperature and patience seems to have more effect.

 

[phettebs]

I think it depends on why it's "stuck." If it's fully fermented out then no, stirring won't help. If it got cold and the yeast settled out, then stirring helps, provided you warm it up as well. :-)

 

[Maysie]

So if my brew was stuck and it is in a temp controlled brew-fridge at 19-19.5C, then stirring it would do little good?

In which case I assume we would be better off raising the temp towards the end as a matter of course?