Increasing my efficiency idea?

I'd call that a prolonged batch sparge. But unless there is otherwise some sort of problem with conversion or with getting the sparge water thoroughly mixed with the grain bed, I don't see how it would increase efficiency, compared to just adding that sparge water to the (drained) grains. mixing, and doing your second drain right away.

 

What is your efficiency that you worry about it? I routinely hit 70% and consider that great. I don’t do anything besides crush finer. I don’t see the use in changing the way I brew to chase a few efficiency points on a Homebrew level.

 

I agree with @VikeMan. That's really just a batch sparge. Volumes and boiloffs are key. If you collect twice as much wort, you'll need to boil twice as long, but it will increase your efficiency significantly to 90% or more, because basically you would be getting maximum sugars out of the grains then concentrating it down a lot. Whereas, if you do like most people including myself and adjust your volumes to result in a more "normal" total amount of preboil wort, then you would be doing an effective batch sparge, and the effect on your efficiency will improve slightly compared to doing the whole mash all at once without a sparge, but probably not much beyond 80%-ish (maybe 83-84% roughly max).

All of this assumes a decent crush of the malt. If your crush is poor, your efficiency will be lower than the max numbers I've given above, but improved over whatever you were getting before. IF it matters.

 

Are you thinking about something like this?
https://metchem.com/mash-filter-press-brewing/

They claim they can get 98% efficiency with this technique.

 

I'm running a 6.5 too and hitting around 66% looking to increase. Do you know the specific size of your crush?

 

I'm not a BIABer, but the ones I know that want to maximize mash efficiency are crushing their grains into near dust and letting the bag/basket continue to drip into the wort through at least part of the boil.

 

The best efficiency I have gotten so far is 64%. I'm going to try to double crush my grains and mash for 90 minutes next time to see if it improves at all.

 

I crush at 0.30 on my mill gap. Slightly tighter than a credit card. My crush is pretty dusty. I don’t sparge but I do squeeze pretty squeeze pretty well for a full volume mash.

 

IMO with BIAB, a small sparge/rinse is better than just squeezing alone. Mash with a little less water, then try dunking into or pouring a gallon or two of hot water over the grain bag after it's pulled, then squeeze as normal. You'll gain a few efficiency points. IF you care.