Grain Temp after Sparge

[abarnard]

I'm working on a blonde ale recipe in the attempt to hone my water adjustment skills and dial in my equipment for bs2.  I just brewed v1.3 and with each attempt I am recording additional data to help diagnose potential efficiency increases.  with this last batch, i recorded post sparge grain temp at 155 degree F.  sparge water has been 175 degree F with each batch.  mash efficiency has been 60-64% with each batch.  shouldn't the grain temp be closer to 170?  should i increase sparge temp on the next batch to help rinse more sugar?  i'm also considering reducing mash temp to help dry out the finish.  Any thoughts or suggestions? 

my setup is a 5 gal gott MLT with another 5 gal gott for hot liquor.  i fly sparge.

blonde recipe: 5.5 gal into the fermenter
9# 2row
.5# C10
mash with 4gal 152F
sparge to get 7gal in the kettle
60 min boil reducing volume to 6gal
.75oz cascade 60min
.25oz cascade 20min
us-05 pitched at 60 F

[Slurk]

Hi Abarnad,

Be careful increasing your sparge water temperature coming over 175 degree F, tannins could start leaching.
Regards,
Slurk

[abarnard]

slurk,

thanks for the reply.  i guess that is the root of my question.  is tannin extraction a function of the water temp or the subsequent grain temp?  I have a sense that by the time the water filters down through the grain bed, it has cooled several degrees.  possibly too much, reducing efficiency.  i would however, prefer to avoid leaching tannins.

[Maine Homebrewer]

I have uses sparge water at 180 without leaching tannins, but that's 180 degree water sprinkling onto a 165 degree mash. It quickly equalizes to a temp that doesn't leach tannins.

[abarnard]

I have uses sparge water at 180 without leaching tannins, but that's 180 degree water sprinkling onto a 165 degree mash. It quickly equalizes to a temp that doesn't leach tannins.

What method do you use to bring your mash to 165? 

[MaltLicker]

I do an infusion of approximately 5 quarts of boiling water.  That infusion will raise the mash about ten degrees and aid lautering and stop some enzyme conversion, but it's low enough that I ignore worrying about it getting the whole mash above 168F. 

I agree with Maine on the limited threat of the sparge being too hot.  I measured my HLT water temp once and it drops quite a bit traveling in the hose from the HLT to the MLT, and then gets mixed with the ~164F water there.  It would have to very overly hot to raise the entire MLT to the danger zone.

[Maine Homebrewer]

What method do you use to bring your mash to 165? 

Single step decoction. I remove a third or so of my mash, bring it to a rolling boil on the stove, keep it there for a few minutes, then mix it back into what was left behind.

I find it easier than trying to raise the temp of the entire mash at once.