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General Category => All Grain Brewing => Topic started by: thehorse on September 09, 2010, 06:26:53 PM

Title: Crazy Attenuation!!!
Post by: thehorse on September 09, 2010, 06:26:53 PM
So I have been seeing some pretty high attenuation lately, and wonder if anyone else has seen numbers like this or would have an explanation for it?  I use the Mr. Malty pitching rate calculator and control fermentation temp.

Could it be that my mash temp is lower than what it reads?
I use a HERMS, does recirculation speed up enzymatic activity making my Mash act as if it were really longer?
Or this is normal?
Is my Hydrometer wrong?

Saison - 1.065 -> 1.002 - 97% AA - Wyeast 3711 (Not sure what to expect on this one), mashed at 147
RIS - 1.098 -> 1.022 - 76% AA - S-05 (Jamil says his only goes to 1.30?), mashed at 154
Dubbel - 1.065 -> 1.006 - 90% AA - Wyeast 3787 (Jamil Says his only goes to 1.012), mashed at 149

I actually really like the RIS and would keep it the same in the future, but I plan on re brewing the Dubbel in a week and a half and want it to finish around 1.012.  Any suggestions?


Title: Re: Crazy Attenuation!!!
Post by: hamiltont on September 09, 2010, 06:35:24 PM
The first two things that come to mind are the hydrometer & thermometer.  I would calibrate both of those first. Cheers!!
Title: Re: Crazy Attenuation!!!
Post by: thehorse on September 09, 2010, 06:36:36 PM
What is the best way to calibrate your thermometer, I'm using thermistors for the BCS-460?
Title: Re: Crazy Attenuation!!!
Post by: tschmidlin on September 09, 2010, 06:38:26 PM
I agree with hamiltont, but I'd also be sure to clean and sanitize everything.  Not all of the bugs that can attenuate your beer will give noticeable off-flavors.  It might not be likely, but it's possible.

Calibrate the thermometer in boiling water and in ice water.  Calibrate the hydrometer in brewing water.

Some recipes would help too, this is the extract section and that would be crazy attenuation for extract.
Title: Re: Crazy Attenuation!!!
Post by: hamiltont on September 09, 2010, 06:43:35 PM
I'm not familiar with the "thermistors for the BCS-460", but here's an article from K-State about calibrating a thermometer.

http://www.ncagr.gov/meatpoultry/pdf/Thermometer%20Calibration.pdf (http://www.ncagr.gov/meatpoultry/pdf/Thermometer%20Calibration.pdf)
Title: Thread Moved
Post by: thehorse on September 09, 2010, 06:44:34 PM
Sorry, I posted in the wrong section.  I'll just restart it over in the all grain section
Title: Crazy Attenuation!!!
Post by: thehorse on September 09, 2010, 06:46:40 PM
So I have been seeing some pretty high attenuation lately, and wonder if anyone else has seen numbers like this or would have an explanation for it?  I use the Mr. Malty pitching rate calculator and control fermentation temp.

Could it be that my mash temp is lower than what it reads?
I use a HERMS, does recirculation speed up enzymatic activity making my Mash act as if it were really longer?
Or this is normal?
Is my Hydrometer wrong?

Saison - 1.065 -> 1.002 - 97% AA - Wyeast 3711 (Not sure what to expect on this one), mashed at 147
RIS - 1.098 -> 1.022 - 76% AA - S-05 (Jamil says his only goes to 1.30?), mashed at 154
Dubbel - 1.065 -> 1.006 - 90% AA - Wyeast 3787 (Jamil Says his only goes to 1.012), mashed at 149

I actually really like the RIS and would keep it the same in the future, but I plan on re brewing the Dubbel in a week and a half and want it to finish around 1.012.  Any suggestions?
Title: Re: Crazy Attenuation!!!
Post by: Mark G on September 09, 2010, 06:54:22 PM
You may also want to try calibrating the thermometer around mash temps against a lab thermometer. I found my thermometers to be off by as much as 4 degrees at a temp of 150F after I calibrated against ice or boiling water.
Title: Re: Crazy Attenuation!!!
Post by: dak0415 on September 09, 2010, 07:00:45 PM
What is your water/grain ratio in the mash?  A high ration (2qts/lb) will result in a more fermentable wort.  Couple that with a temperature error and you have your result.
Title: Re: Crazy Attenuation!!!
Post by: thehorse on September 09, 2010, 07:16:58 PM
I used a 1.5qt/lb ratio on all batches except the RIS which was 1.25qt/lb because of mash tun size?

Does anyone know where can I buy a calibration thermometer for Mash temps?
Title: Re: Crazy Attenuation!!!
Post by: saintpierre on September 09, 2010, 07:25:15 PM
Do you live at altitude? If you live close to sea level water should boil at 100C (212F).  Check the low end by filling an insulated coffee mug with ice and water let stabilize should be close to 0C (32F).

Also I remember an equipment calibration article in BYO from a little white ago.

No need to buy something new calibrate what you already have. My 2cents...
Title: Re: Crazy Attenuation!!!
Post by: CASK1 on September 14, 2010, 04:32:40 PM
3711 is a vigorous attenuator. With a 147 mash temp, I'm surprised it didn't finish lower...
Title: Re: Crazy Attenuation!!!
Post by: a10t2 on September 15, 2010, 12:00:25 AM
All three of those numbers look totally normal to me.
Title: Re: Crazy Attenuation!!!
Post by: gordonstrong on September 15, 2010, 03:45:16 PM
Attenuation is driven more by the fermentability of the wort than the yeast strain used.  If you provide the right conditions, yeast will ferment what you give them.  I'd look more at what is driving your fermentability. My first thought is that your thermometer might be reading high, but it could also be the type of malt you're using or the amount of sugar you are adding. Providing your full recipe would help.

But those numbers really aren't out of line.  First all grain batch I did was a dubbel using 3787 and I wound up finishing at 1.008.  You learn how to control your process on your system.  Adjust accordingly.  Mash higher, add some carapils or other dextrinous malt, add more crystal malts, etc.

I don't think recirculating has anything to do with it, unless you are raising the temperature after you mash in, thus giving you some benefits of a step mash.

Most brewers would kill to be able to get full conversion and attenuation at will.  Consider yourself lucky, and adjust upwards if you want to have a higher FG.
Title: Re: Crazy Attenuation!!!
Post by: thehorse on September 15, 2010, 04:46:01 PM
Thanks Gordon, I'm brewing the Dubbel again next Saturday so I'll just bump up my mash temp and see what happens.  I'll probably shoot for 151, and see what that does.
Title: Re: Crazy Attenuation!!!
Post by: kylekohlmorgen on September 15, 2010, 04:52:04 PM
I wouldn't give up on them either...

When I have a beer finish a bit low on gravity, I'll taste it to see if the mouthfeel is where I want it. If it needs more body, I'll add some malto-dextrin before I keg (or bottle) just like you would with priming sugar.

Start with a half-pound and work your way up. Use 2 qts (or less) water. That will add ~ 2 pts to your FG, but go by taste, not by the numbers.

I wouldn't go more than 10-15% of MD total.
Title: Re: Crazy Attenuation!!!
Post by: thehorse on September 16, 2010, 04:21:46 PM
Will Malto-Dextrine add any sweetness or will it only add body?  I'm tempted to add a little sweetness back to the saison and was considering lactose, any thoughts?
Title: Re: Crazy Attenuation!!!
Post by: Mikey on September 16, 2010, 06:24:22 PM
Pretty hard to just add in body without some sweetness along with it.
Title: Re: Crazy Attenuation!!!
Post by: tschmidlin on September 16, 2010, 06:44:29 PM
Will Malto-Dextrine add any sweetness or will it only add body?  I'm tempted to add a little sweetness back to the saison and was considering lactose, any thoughts?
In my experience, it will add some perceived sweetness for sure.
Title: Re: Crazy Attenuation!!!
Post by: smoga on September 16, 2010, 07:28:36 PM
Malto-Dextrin to a Saison? really?
I tried it in a sweet stout. Didn't like it.
I just would not "ruin" a nice dry saison with malto.
Bottle up a few with it. see if you like it.

That 3711 is crazy a attenuative yeast. I have gone as high as 1.100 with it and seen it finish below 1.008

BTW - I highly recommend trying Wy 1968 (London ESB) in the RIS next time.
I won Best of Class ale in the local county (Kitsap WA) homebrew competition with that combo.