[thehorse]

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?

[hamiltont]

The first two things that come to mind are the hydrometer & thermometer.  I would calibrate both of those first. Cheers!!

[thehorse]

What is the best way to calibrate your thermometer, I'm using thermistors for the BCS-460?

[tschmidlin]

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.

[hamiltont]

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

[thehorse]

Sorry, I posted in the wrong section.  I'll just restart it over in the all grain section

[thehorse]

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?

[Mark G]

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.

[dak0415]

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.

[thehorse]

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?

[saintpierre]

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...

[CASK1]

3711 is a vigorous attenuator. With a 147 mash temp, I'm surprised it didn't finish lower...

[a10t2]

All three of those numbers look totally normal to me.

[gordonstrong]

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.

[thehorse]

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.