Extreme attenuation, Why?

[Druncan]

Just kegged four 23l batches of Sandancer, a 4% cream blonde recipe I brew. :thumb:
Made with 2.4kg Muntons LME 1200 g Dextrose 20g hop tea and 7.5g of hydrated @ 35*C BRY97. All liquor within usual limits. Temps as planned.

Starts @ 1.040, bang on. Heavy krausen, vigorous fermentation. 5days later 1.016. Dry hop 50g FF t90 pellets. Two days later 1.008 but still bubbling. Left 3 days till it stops. Chill 2days @ 12*c. Kegged, smells great and 20*c samples on all four are 1.004/5. So 4.5/4.6% ABV.:grin:
My hygrometers and thermometer are HMRC level accuracy.
THat is an app attenuation of 90%? Ihave never had attenuation to that level. Any ideas why?
It was a fresh batch of LME and BRY though,,,,,,

 

[TheQuokka]

What temperature did you ferment at?

35C is a bit high to rehydrate at, but shouldn't kill much yeast and any infection capable of dropping SG that much would have notable flavours. So I suspect fermentation temps were a bit high for the yeast.

 

[dad_of_jon]

Just kegged four 23l batches of Sandancer, a 4% cream blonde recipe I brew. :thumb:
Made with 2.4kg Muntons LME 1200 g Dextrose 20g hop tea and 7.5g of hydrated @ 35*C BRY97. All liquor within usual limits. Temps as planned.

Starts @ 1.040, bang on. Heavy krausen, vigorous fermentation. 5days later 1.016. Dry hop 50g FF t90 pellets. Two days later 1.008 but still bubbling. Left 3 days till it stops. Chill 2days @ 12*c. Kegged, smells great and 20*c samples on all four are 1.004/5. So 4.5/4.6% ABV.:grin:
My hygrometers and thermometer are HMRC level accuracy.
THat is an app attenuation of 90%? Ihave never had attenuation to that level. Any ideas why?
It was a fresh batch of LME and BRY though,,,,,,

did you change anything? maybe warmer fermenting temps. I re-hydrate yeast at between 30-35 deg C as per MJ's instructions. I assume the ferment temps were around 20 deg? - i'd put it down to being a fresher better stored packet of yeast which had more viable cells than your usual packets.

 

[Druncan]

What temperature did you ferment at?

35C is a bit high to rehydrate at, but shouldn't kill much yeast and any infection capable of dropping SG that much would have notable flavours. So I suspect fermentation temps were a bit high for the yeast.

Yup, 30-35 is the temp I was advised to rehydrate @ by lallemand's expert @ the SIBA beerx. I do 35*C then it cools a bit as It hydrates. More critical apparently is using the solution before 30mins has elapsed. I have been doing this, and starting is faster! Closer to SA05.

No off flavours at all, in fact it was so tasty and fragrant, had to have a quick half for QC purposes,,,,, :grin:

Temps were 18.5 - 21.5 and unchanged from previous Gyles.

I agree, most likely the freshness and higher viability. But what a fantastic improvement:thumb: looking forward to a comparison once they are conditioned,,,,

 

[DoctorMick]

Isn't 1.040 to 1.008 an apparent attenuation of 80%?

 

[Druncan]

Isn't 1.040 to 1.008 an apparent attenuation of 80%?

Hi Mick, well 1.008 was my usual FG. This actually went to 1.0045 (see OP) that I worked out to 90%,,,,, but, it's the first time I worked out AA's so i'm probably wrong,

Just a thought, is your avatar Newcastle on Tyne bridge? That was near where I was originally from, born in St Mary's in the Toon, but lived in South Shields, hence my beer 'Sandancer' Seems like there is a lot of North East brewers on the HBF!!! Is it 'cos we'r 'canny' lads and divn't like payin ridiculous prices for a brew:lol:

I'm now going to try my APA that usually comes in @ 6.5% with 100g FF7c's.
If that drops to the same level that'll be 7.3% ABV!!!

 

[Grizzly299]

The fermentability of your spraymalt may have been higher for some reason. Perhaps due to a manufacturing problem or a difference in the manufacturers raw materials. The other batches may have had more long chain sugars, where as this one may have had more short chain sugars than previous batches.

Another possibility is Wild yeast.They can dry out your beer if they manage to take hold. A beer that keeps getting dryer usually indicates a wild yeast infection.

If it carbs up more than you're expecting and becomes more tart and fruity then you may well have a wild yeast infection.

 

[chthon]

A quick calculation shows that 2.4 kg of LME would attenuate to a residue of 480 g unfermentables. And you add 1.2 kg dextrose, which is completely fermented away. Which means that you start with about 3.6 kg of fermentables, and get at the end 480g residue. This translates into 85% apparent attenuation.

 

[DoctorMick]

Hi Mick, well 1.008 was my usual FG. This actually went to 1.0045 (see OP) that I worked out to 90%,,,,, but, it's the first time I worked out AA's so i'm probably wrong,

Just a thought, is your avatar Newcastle on Tyne bridge? That was near where I was originally from, born in St Mary's in the Toon, but lived in South Shields, hence my beer 'Sandancer' Seems like there is a lot of North East brewers on the HBF!!! Is it 'cos we'r 'canny' lads and divn't like payin ridiculous prices for a brew:lol:

I'm now going to try my APA that usually comes in @ 6.5% with 100g FF7c's.
If that drops to the same level that'll be 7.3% ABV!!!

It's the Wearmouth bridge. :evil:

I'm not up that way anymore either but I suspect you're right, the reason we brew is because we're tight. :lol: