Batch Sparge temperature question

In a recent batch sparge I did, I tried to target my sparge temp to 170 degrees. However, I messed u a little and it ended u being 158 deg. So I soaked and stirred for 15-minutes, collected and went on with my brew. But it got me thinking:

Wouldn't the temperature of the batch sparge be somewhat arbritary? I mean as long as its >150 or so degrees to have maximum solubility of the sugars, why would it matter if its at 170 degrees or not for the (batch) sparge if all we are doing is rinsing the grains of residual sugar.

Also, the temperature of the strike water needed to add to the grains would have to be high (185+) and in the instant when they hit the grains before the temperature is equilibrated, this would lead to tannin extraction no?

This is only my second brew, my first brew my sparge ended up 170 on the nose, but this one came out lower, and I was left wondering, does it matter?

Thanks

UltraHighABV said:

Wouldn't the temperature of the batch sparge be somewhat arbritary?

Click to expand...

Yes. You could sparge with ice water if you wanted to.

The only reason to sparge hotter is to reach mash out temperatures- however, since you're putting the runnings on the burner right away (unlike continuous/fly sparging), even that doesn't matter.

Kai Troester (braukaiser.com) showed data where cold water batch sparging has the same efficiency results as warmer water.

There is a theory that warmer water means the sugars are more dissolved and fluid, so easier to capture when the sparge liquid is warmer, but that doesn't even make sense when you think about it.

I noticed no difference in efficiency when I batch sparged with 160F water and 180+ water. Only thing is it took longer to get to a boil.

Kai's experiment that Yooper mentioned is reported here: http://braukaiser.com/blog/blog/2009/05/12/cold-water-sparging/. The important thing for cold water sparging to work as well as hot water sparging is that your starch to sugar conversion is complete (this was the case in Kai's work.) If your mash time is too short, and conversion is not complete, then a hot water sparge can give you more efficiency. This is because the time spent mixing and running off the sparge effectively extends the mash time, and allows for some more conversion to occur.

At 151.3°F (66.3°C) one gal of water can dissolve about 16.5 lbs of maltose. This equates to 66.7°Plato or an SG of about 1.334. You don't need higher temps to keep the sugar in solution. Water at 70°F can dissolve about 6.6 lbs of maltose or an SG of 1.200. Still plenty of solubility to keep all of the sugar in solution. And your sparged wort will have much less sugar than your first runnings wort.

Brew on

This is a good question op as I've often wondered the same thing re adding really hot water to the grain to reach mash out temp. For instance I have to sparge with up to 200deg water to get my grains back up to 168 after I drain my first runnings. The only thing I can think of on the opposite side of this thought is that once that water hits the grain the temp drops severely so your not letting the grains sit in 200deg water due to temp absorption by the grain the temp goes almost immediately from 200 to 168-170 deg and that's really where you want it at from what I understand. But 20+ batches in I've found doing no mash out I need to heat that first sparge up to 190-200 depending on the temp of the drained grain bed to get it up to mash out temps of 168-170.