Relationship between mash temp and attenuation?

[Rolly]

Is there some sort of linear equation that would show the average change in apparent attenuation based on a change in mash temp? For example, if I have a yeast that is supposed to average 75% attenuation at a mash temp of 152, what attenuation would I expect at a mash temp of 156?

The reason I ask is that I've done two batches, an ipa 1.065 and a brown ale, 1.060 both with wlp 007 and they finished at 1.020 and 1.022 respectively. I consider this unacceptable for this yeast. I always do starters on a stirplate, pure O2 with stone, and temp control.

What I did find out is that while my mash thermometer is calibrated for 32 at freezing, when I test it in boiling water it reads 209.5. Is it possible that this threw my attenuation off that much?

 

[Clementine]

Not exactly but I read a good brew wiki on it a while ago with some interesting tests. This one is a start but it is not the exact one I read which was talking about fermentability of a wort based on temp.

https://www.homebrewtalk.com/wiki/index.php/The_Theory_of_Mashing

Clem

 

[day_trippr]

fwiw, I checked the altitude ASL for Petaluma just in case it was up in the mountains - which would affect what the actual boiling point of water would be (higher ASL = lower boiling point). Looks like you're somewhere below 400' ASL so your water should indeed boil at 212°F.

All other things being equal - in particular, the duration you let the mash set during dextrinization - if your mash thermometer is reading lower than the actual temp, the resulting wort will shift towards the less-fermentable side.

That said, 2.5 degrees F isn't that big of an error - if it were off by 5 degrees that would be a lot more significant...

Cheers!

 

[PantherCity]

I love 007, but it is very flocculant. I tend to bump the temps when activity is slowing down and I rouse the yeast as well. I never understood people who are afraid to touch their fermenting vessels.(I'm not suggesting you are one of these people.) Especially if there is still some air lock activity you know that only co2 is in the head space.

 

[permo]

Is there some sort of linear equation that would show the average change in apparent attenuation based on a change in mash temp? For example, if I have a yeast that is supposed to average 75% attenuation at a mash temp of 152, what attenuation would I expect at a mash temp of 156?

The reason I ask is that I've done two batches, an ipa 1.065 and a brown ale, 1.060 both with wlp 007 and they finished at 1.020 and 1.022 respectively. I consider this unacceptable for this yeast. I always do starters on a stirplate, pure O2 with stone, and temp control.

What I did find out is that while my mash thermometer is calibrated for 32 at freezing, when I test it in boiling water it reads 209.5. Is it possible that this threw my attenuation off that much?

I use WLP007 all the time and I find it attenuates like nuts under virtually all circumstances. I would ensure that you are pitching a proper amount of healthy yeast and try some yeast nutrient. I would use a starter in the 2 liter range for a 1.065 ale (five gallons).

 

[wildwest450]

A step mash will also help with attenuation.

_

 

[Clementine]

I found the article I read that I was originally looking for with this thread

http://braukaiser.com/wiki/index.ph...ity_and_efficiency_in_single_infusion_mashing.

It covers more than what you were looking for but will answer your question and a few more.

Clem