how much to raise mash temp to avoid over attenuation?

[jedheuer]

Hello,


I recently made a witbeer and a belgian blonde and both ended up over attenuating. the witbeer should have finished at 1.011 but ended up at 1.005 and the blonde should have been 1.012 but ended up at 1.004. On both i hit my mash temps according to the recipe. I have confirmed my hydrometer and thermometer are properly calibrated as well. This is the first time I am using the belgian pilsner malt so i have narrowed it down to this malt being more fermentable than the 2 row and pale i have been using in other recipes.

So my question is... for the belgian blonde to finish at 1.012, how much should I raise the mash temp? I would think not more than one or 2 degrees? What do you all think? or should I cut the amount of simple sugar from the recipe so it drys out less (there was 1.5 pounds in a five gallon recipe)?


Thanks!

 

[Hammy71]

What was the orginal mash temp(s)?

 

[jedheuer]

the blond was 150 for about 60 minutes and the wit was 122 for 15 mins and then raised to 154 for another 45 minutes.

 

[Hammy71]

And your damn sure you thermometers are accurate? Getting down to .05 is pretty low, even for 150. I would suggest maybe the sugar is the culprit.

 

[Wynne-R]

Have you considered a mash-out?

 

[BanginBanjo]

Without seeing the recipes, mashing the blonde at 150 along with 1.5lbs of sugar would result in a pretty dry beer I would think. You could try raising the mash temp to 152 or so, but I would also think about cutting down on the sugar, that's probably the biggest culprit. Also, check your apparent attenuation compared to the range for the yeast strain your using, that might tell you something. Fermentation temperature can also play a role in attenuation, higher temps can lead to higher attenuation.

 

[jedheuer]

Without seeing the recipes, mashing the blonde at 150 along with 1.5lbs of sugar would result in a pretty dry beer I would think. You could try raising the mash temp to 152 or so, but I would also think about cutting down on the sugar, that's probably the biggest culprit. Also, check your apparent attenuation compared to the range for the yeast strain your using, that might tell you something. Fermentation temperature can also play a role in attenuation, higher temps can lead to higher attenuation.

Recipe is from Brewing Classic Styles:
11 pounds pilsner malt
0.5 wheat malt
0.5 aromatic
1.5 cane sugar

I fermented at 64 and raised it over the course of 4 days to 68. I used WLP 500.

And your damn sure you thermometers are accurate? Getting down to .05 is pretty low, even for 150. I would suggest maybe the sugar is the culprit.

Yes, maybe the sugar could come down a bit. I thought .05 to be super low as well to the point of a wild yeast being the culprit, but there are not off flavors to speak of, so i dont think so.

Have you considered a mash-out?

Yes, I am doing a mash out step to abut 165-168 before lautering.

 

[helibrewer]

I would expect that dryness with 20% sugar but not 10%. Also, the wit is probably close to 50% wheat and getting that down to 1.005 is pretty darn low...what are you using to measure mash temps?

 

[jedheuer]

I would expect that dryness with 20% sugar but not 10%. Also, the wit is probably close to 50% wheat and getting that down to 1.005 is pretty darn low...what are you using to measure mash temps?

That is a good point. Yes, it was about 50% flaked wheat. I am using a Taylor digital thermometer calibrated to 32 degrees F., using ice water. I also have a thermometer on my mash tun that is calibrated to the Taylor thermometer. They read the same but the on on the mash tun takes longer to respond to temp changes, so i typically just check it with the hand held digital. I will double check the thermometer, but it has been calibrated recently.

 

[GrogNerd]

was reading thru this thread earlier

mash temp is not the only thing affecting attenuation; mash time and your water:grist ratio are variables too

longer times and/or thinner mash = more fermentability

 

[tagz]

Check the boiling temp calibration as well. When I discovered my thermometer was off it read 34* for the ice bath and 218* for boiling water. So, it was more pronounced on the higher temps. I had three batches end in the 1.005 range. They were all super thin and disappointing.

 

[ajf]

was reading thru this thread earlier

mash temp is not the only thing affecting attenuation; mash time and your water:grist ratio are variables too

longer times and/or thinner mash = more fermentability

I agree about the mash time, but not the mash thickness. I use 1 qt per lb grain, and regularly achieve > 80% apparent attenuation using WLP002, which according to White Labs should give 63 - 70% attenuation.

-a.

 

[GrogNerd]

I wish I knew the answer to this, but I don't.
In How to Brew, Palmer states that a thick mash results in a less fermentable wort.
In New Brewing Lager Beers, Noonan states "A thick mash (less than three-tenths of a gallon pre pound of malt) induces the greatest overall extraction. A much thinner mash increases the proportion of maltose, and thus wort attenuation."
In Designing Great Beers, Daniels states that a mash thickness of 1 qt per lb is traditional for English beers.
What I can say, is that if I mash at 1 qt per lb, I get a beer with lots of "mouth feel" which would imply a wort with lots of dextrins, hence less fermentable, or lower attenuation. If I mash at 1.25 qt per lb or greater, then I lose the "mouth feel", implying fewer dextrins and greater attenuation.
The problem is that I can detect no difference in attenuation between a mash at 1 qt / lb and a mash at 1.25 qt/lb but there is a vast difference in the character of the beers produced with these different mash thicknesses.
I would recommend trying a couple of brews, one with a thick mash, and one with a thinner mash, and see if you can detect the difference.
If you can detect the difference (which I think you will), then you should decide which one you like best.

-a.

Palmer & Noonan agree and you said you can taste the difference, but not measure it.

but I'll agree that time & temperature have the greater effect, thickness much less so. in your case, I would guess there are other variables that are causing your increase in attenuation

 

[Bsquared]

How did you measure your FG? 1.005 is really low.

 

[jedheuer]

Well, to update the thread here, I double checked my thermometer and i is accurate. Also double checked my hydrometer and it is accurate, so I know that my ways of measure are good.

Also I made an ale with 2row (not the belgian pils that I think might be over attenuating) and it was spot on at the projected finishing gravity. So I am leaning towards my original theory of the belgian pils malt being slightly more attenuative than it should be (or is expected to be). To test this I made a dubbel and upped the mash temp one degree. Hopefully it will finish closer to the projected FG due to this adjustment. I will have to wait 2 weeks to find out.

 

[tagz]

Interesting. Keep us posted.

 

[jedheuer]

Well to update the thread again, the dubbel finished out to high. So i guess my theory was wrong about the pilsner malt being overly fermentable. I will keep playing with the belgian yeast until I figure it out.

 

[rustym]

I brewed this exact same recipe recently but I mashed at 152-153, and I mashed for 90 minutes instead of 60. My SG was 1.070 I finished at 1.015 for about 78-79% attenuation. White labs says to expect 75-80% attenuation.

Maybe raise the mash temp? It sounds like everything else you did was spot on.

 

[tagz]

I recently discovered that one of my problems was variation in temp in my cooler. The middle of my mash would show 152, but i realized the edges were in the mid 140s. Pre-heating and stirring like crazy at the start of the mash helps.

 

[rustym]

I recently discovered that one of my problems was variation I temp in my cooler. The middle of my mash would show 152, but i realized the endges were in the mid 140s. Pre-heating and stirring like crazy at the start of the mash helps.

+1 on this! I just brewed this again yesterday and mashed at 152. My SG is 1.068. I did mash for 90 minutes again instaed of 60. My cooler MT holds temps very well and I think it improves my efficiency. I'll post bak when I get my FG and see what the attenuation ends up to be,

 

[jedheuer]

+1 on this! I just brewed this again yesterday and mashed at 152. My SG is 1.068. I did mash for 90 minutes again instaed of 60. My cooler MT holds temps very well and I think it improves my efficiency. I'll post bak when I get my FG and see what the attenuation ends up to be,

This is a good point. I have measured different areas of the mash bed and it does vary quite a bit. I just built a PID controller though so i can recirculate while mashing for more stable and even temps. so i will try it again with this in place next time.

 

[rustym]

Well, interesting! I brewed this exactly a week ago. I pitched at 64 degrees and rose the temp 1 degree a day and ended at 68 degrees. I checked my gravity and I am at 1.008! I mashed at 152-153 also. I think the sugar just may be the issue here.

 

[MrKrinkle151]

Recipe is from Brewing Classic Styles:
11 pounds pilsner malt
0.5 wheat malt
0.5 aromatic
1.5 cane sugar

I fermented at 64 and raised it over the course of 4 days to 68. I used WLP 500.



Yes, maybe the sugar could come down a bit. I thought .05 to be super low as well to the point of a wild yeast being the culprit, but there are not off flavors to speak of, so i dont think so.



Yes, I am doing a mash out step to abut 165-168 before lautering.

I believe the cane sugar in this recipe is for the extract version in order to bring down the FG, since it does raise the OG and drop the FG much lower than what is quoted in the book with all grain. Removing the cane sugar in Beersmith results in numbers that match those in the recipe.