Stuck fermentation - re-aerate?

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Stuck fermentation - re-aerate?

Postby Lugsy51 » Wed Aug 13, 2014 01:00

Hi all

I have a very stubborn Dubbel on the go. OG was 1.062, current gravity is now 1.028 after ten days. Mash temperature was 66C but I think I pitched a bit warm in my rush to get away camping for the weekend, maybe 25C. It's been slowly dropping at about 1 point per day for the last 5 days following repeated rousings and a gentle increase of temperature from 20C up to 24C now. I'm using second generation WLP530 which was cropped fresh from a Belgian Pale I did a couple of weeks earlier (slurry, not top-cropped) so I think the initial pitching temperature was too high and it's worn itself out after the initial activity and heat. I think it's got at least another 15 points to drop before it's finished so I'm thinking about introducing a bit more oxygen to get it going again but I'm a bit worried that it's getting late in the day for this. Does anyone have any tips for me?

Also, I'm planning an addition of Candi Syrup when I'm nearly at FG. I'm reluctant to add it just yet as I don't want the yeast to get lazy on simple sugars before it's finished on the malts.

Cheers,

Ian
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Re: Stuck fermentation - re-aerate?

Postby Bad 'Ed » Wed Aug 13, 2014 06:01

I know that airation is a bad plan once you have alcohols formed in the wort. I assume you've tried just giving it a stir? I doubt 25c would be high enough to damage the yeast.

Never enough time....
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Re: Stuck fermentation - re-aerate?

Postby GrahamT » Wed Aug 13, 2014 10:22

I guess I'm now fairly used to using fresh wlp530 vials in stepped starters in 1.075/1.080 wort, so a little different, but I have got to around 1.030 in around 10 days starting at 17C for the first few days and steadily upwards to 24C after than, taking a further 11 days or so to fully attenuate. Even with a big starter, this yeast (which is fantastic) is known to take ages for the last few points.

One thing I have noticed is that it hates a drop in temperature. Not sure how long yours was at 25C, but I'd certainly rouse (not aerate) and take it back to 25C. I had my last one sat at 24 for the last two weeks of three. If it's moving though, it's not 'stuck'.

Hope that helps a little, even if it's not quite the same.

PS my sugars have been in from the start each time, without problem, so far...

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Re: Stuck fermentation - re-aerate?

Postby Lugsy51 » Thu Aug 14, 2014 00:40

That's good to hear Graham. It still has a krausen and I keep gently rousing it, I've upped the temperature to 26C now but I think after the initial activity it dropped to around 20C or so. I think I'll add the candi syrup tomorrow and see what happens. I'm planning on top-cropping some of the yeast for re-seeding my Belgian Dark Strong which has been bulk ageing for 8 months now, it's currently at 12.5% ABV so I think it'll need a little help to carbonate in the bottle - the original WLP545 must be pretty tired by now!

Cheers for the replies :thumb:

Ian
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