Author Topic: WLP005 - Underattenuating?  (Read 897 times)

Offline Hand of Dom

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WLP005 - Underattenuating?
« on: April 02, 2016, 12:52:10 PM »
I've had a smoked porter in the brewfridge for that past fortnight.  Fermented at 18.5c for the first 6 days, before upping to 20c for the last 7 days.  The SG was 1055, and it's got down to 1024.  This works out as about 55% attenuation, which is rather lower than I was expecting (was hoping for it to reach 1018).  Grain bill was as follows, and was mashed at 69c for 60mins:

50% Maris Otter
20% Rauchmalt
10% Flaked Oats
5% Biscuit
5% Carafa 3
5% Roasted Barley
5% Brown malt

I'm going to give the bucket a gentle swirl to try and rouse the yeast, but is there anything else I can try to get it going.
Dom

Currently drinking - Amarillo saison
Currently fermenting - Pale ale 1 - 2017

Offline Hand of Dom

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Re: WLP005 - Underattenuating?
« Reply #1 on: April 02, 2016, 01:19:56 PM »
Bit more info, yeast was a 2L starter, that was pitched at high krausen (full 2L).
Dom

Currently drinking - Amarillo saison
Currently fermenting - Pale ale 1 - 2017

RPIScotty

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Re: WLP005 - Underattenuating?
« Reply #2 on: April 02, 2016, 01:56:37 PM »
High mash temp and 30% roast/adjunct ingredients? Did you hit your target gravity? From the other thread on batch size you said you do 20L, so you pitched quite a bit of starter wort in (~10%), and maybe that had something to do with it?


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Offline dmtaylor

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Re: WLP005 - Underattenuating?
« Reply #3 on: April 02, 2016, 02:01:25 PM »
WLP005 is an English style yeast, and in general, English yeasts tend to flocculate out very quickly and they tend to attenuate less than most other yeasts.  As such, rousing the yeast is a very good idea but might not work.  It's worth a try though.  You could also warm it up even more, maybe to 22 C.  You could also try adding a starter of a more highly attenuating yeast such as WLP001 or US-05 to get it rocking again.  If you try this, it must be a vigorous starter -- if you only add a pack of yeast and skip making a starter with the new yeast, it probably wouldn't do a darn thing.  But a vigorous starter with a more highly attenuative yeast is likely to get it going again.  Then wait a couple weeks and hope for the best.
Dave

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Offline Hand of Dom

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Re: WLP005 - Underattenuating?
« Reply #4 on: April 02, 2016, 02:25:27 PM »
High mash temp and 30% roast/adjunct ingredients? Did you hit your target gravity? From the other thread on batch size you said you do 20L, so you pitched quite a bit of starter wort in (~10%), and maybe that had something to do with it?


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  I was slightly under my target SG (1055 rather than 1060), which I put down to milling my grain coarse (had never sparged previously, and wanted to avoid a stuck sparge).  I've made the beer previously, with the only change in recipe being to up the smoked malt from 15% to 20% (and reducing the MO by 5%).  I got about 65% attenuation last time out, and if I can get that again I'll be happy, as that beer was great.  To be honest, I think I only really need to find a couple more points, as the sample I took tasted good, but would like to lose the slight sweetness I'm getting beyond the smokiness.

I'll keep an eye on it, and give it a regular swirl.  If I don't see any movement, I'll make a small starter with Nottingham, and see if that can get me to 1020.  I wanted a high FG for this beer, just not quite this high.
Dom

Currently drinking - Amarillo saison
Currently fermenting - Pale ale 1 - 2017