[dean]

I've read where other people have said their efficiency goes up by slowing down their runoff and thats the only thing I could think of that it might impact, but adding ten minutes doesn't seem like enough time to make much of a difference.  I generally start slow and then open the valve completely.  The only part that sometimes bothers me is at the end of a run, I almost panic when it gurgles.   

[denny]

Yeah, while it makes some sense, you;d have to check the gravity throughout the runoff, as Kai suggests, to confirm it.  I can tell you that I runoff all the wort for a 5.5 gal. batch (about 7.5-8 gal.) in 15 min. of less.  That includes mash runoff, stirring in the sparge water, vorlauf, and sparge runoff.    That's about as fast as I can go.  So it looks like my fastest time is about what fritzeye slowed down to.

[Kaiser]

I've read where other people have said their efficiency goes up by slowing down their runoff and thats the only thing I could think of that it might impact,

You need to make a distinction between batch and fly sparging here. In fly sparging the efficiency of the lauter process is sensitive to the run-off speed. It batch sparging it is not. But that does not mean that there is not the possibility that a slower run-off in batch sparging can gain overall efficiency. In particular if there are still conversion processes happening in the mash.

Has anyone ever conducted the test where the gravity of the mash is tested after adding and stirring in the sparge water and then after a 10 min sparge rest and another good stir?

Kai

[a10t2]

Has anyone ever conducted the test where the gravity of the mash is tested after adding and stirring in the sparge water and then after a 10 min sparge rest and another good stir?

I have, but only once. There was no change. Which makes sense to me - after an hour of mashing my conversion efficiency is always >90% anyway.

edit: I should add that I stir constantly for 2-3 minutes after adding the sparge water anyway. If you weren't doing that I could understand why there would be a benefit.

[denny]

Has anyone ever conducted the test where the gravity of the mash is tested after adding and stirring in the sparge water and then after a 10 min sparge rest and another good stir?

Kai

I did about 8-9 years ago, which is about when I started questioning if a rest after adding the sparge water was necessary.  At that point, it didn't seem to change anything.  But I'll try it agin and take better notes.

[Kaiser]

This might be a test worth trying on a mash with a coarse grist. Many brewers argue that during sparging the sugars, which are converted but still in the grits, diffuse out of those grits. If that is the case then you should see the gravity of the wort increase during a sparge rest. But I’m convinced that most of the sugars have already diffused into the wort during the 60 min of mashing and all we are trying to do during sparging is to wash those sugars off the spent grain particles. Though there will be some diffusion out of the grain particles as well I would expect that to be minimal.

Kai

[denny]

I'm in agreement with your hypothesis, Kai.  And I won't be testing a coarse grist since that would require me to readjust my mill.  I'm not gonna mess with that.

[bluesman]

I usually stir once after adding the sparge water. I believe additional stirring wouldn't render any significant amount of additional sugar assuming one has achieved starch conversion during the mash.

[denny]

I usually stir once after adding the sparge water. I believe additional stirring wouldn't render any significant amount of additional sugar assuming one has achieved starch conversion during the mash.

That's been my experience.

[Kaiser]

I'm in agreement with your hypothesis, Kai.  And I won't be testing a coarse grist since that would require me to readjust my mill.  I'm not gonna mess with that.

No, I was not really soliciting volunteers.

Kai

[denny]

I'm in agreement with your hypothesis, Kai.  And I won't be testing a coarse grist since that would require me to readjust my mill.  I'm not gonna mess with that.

No, I was not really soliciting volunteers.

Kai

I realize that, but my facetiousness level was low.....