Batch Sparge Runoff Rate

It is often said that the speed of the post-vorlauf runoff does not impact efficiency when batch sparing, but am wondering if this is fact or brewing myth.

I know we are rinsing the grains, but it seems that a slower runoff could boost efficiency. Anyway, I am thinking about doing this experiment, but want to solicit feedback from the forum based on their experiences.

I don't see it happening. A slower runoff might give you an extra minute or two of conversion, but with modern US 2 row malt, you have conversion in as little as 20 minutes. I can't see any other ways that it would raise your efficiency, but I am certainly open to any ideas.

I depend on stirring the sparge for maximum sugar removal, then drain as fast as it will run.

I am listening to a Can You Brew It show on the Brewing Network and they just said that a brewpub went to a coarser grind and slowed it's sparge rate down and increased efficiency by 8%. I'm sure they are fly sparging but it's worth a shot if you ask me. It's the CYBI from 5-9-2011 at about the 54:14 mark.

asdtexas said:

... it seems that a slower runoff could boost efficiency...

Click to expand...

How? What's your logic?

Brutus Brewer said:

I am listening to a Can You Brew It show on the Brewing Network and they just said that a brewpub went to a coarser grind and slowed it's sparge rate down and increased efficiency by 8%. I'm sure they are fly sparging but it's worth a shot if you ask me. It's the CYBI from 5-9-2011 at about the 54:14 mark.

Click to expand...

I'm sure that's true of fly sparging, but not with batch sparging. With batch sparging, the idea isn't to use diffusion to slowly "pull" the sugars into the water like it is with fly sparging. Instead with batch sparging, you stir to get the sugars into solution and then drain rapidly. Letting it sit may actually decrease the efficiency, since the sugars knocked into solution from stirring can then go back and cling to the grain while sitting.

I find at a certain point I can't get clear run off and I drain just slower than that. Or if I'm in a hurry I just run off as fast as it will go. Doesn't seem to make much of a difference in the final product.