Batch sparging with larger mash tun

I recently acquired a 10 gallon cylindrical cooler that I'm going to use for the first time this weekend. I wanted the larger cooler so I could make higher gravity all grain beers. However, I'm not sure what batch sparge approach I should take.

The recipe I'm making calls for 16 lbs. in a 5.5 gal batch. I typically use 1.25 Qt./lb, so I'll be mashing in with 5 gallons of water, and lose about .5 Qt/lb to the mash. With no mash out, I'll get 3 gal. out of my first runnings. I need 6.5 gallons into the kettle.

What I'm confused about is how I should get the other 3.5 gallons. With the lower gravity beers I've brewed on my 5 gal. tun, I use two batch sparges, each at 1/2 the volume of the amount I need to top up the kettle. In this case, however, I don't know if two sparges at 1.75 gal. (7 Qt) each will be enough. I'm thinking of taking one of these approaches, but not sure which is right:

1) Mash in at 1.25 Qt./lb, use two batch sparges at 1.75 Gal. each
2) Mash in 1.25 Qt./lb, add 1 Qt of boiling water to mash out and get 3.25 gal, then sparge to get a second 3.25 gal to fill the kettle. This way I'll match my first and second runnings, which I've heard maximized efficiency.

This is my first time with a higher gravity beer, and with the new equipment. I know I'll need to make adjustments on future brews, but want to start out on the right foot. Any recommendations?

Go with option #2 because a sparge of 1.75g in 16 pounds isn't going to be fluid enough to stir very well.

My efficiency has jumped significantly since I started adjusting my mash thickness to leave me with 4 gallons of sparge water (2 rounds of 2 gallons each). Perhaps it has to do with my water chemistry, but my conversion efficiency has been much better with a thicker mash. Obviously my lauter efficiency is also much better with more sparge water.

Thanks, guys. EvilGnome6, I'd read that a thicker mash resulted in less efficiency. Maybe that was for no-sparge brewing--I don't quite remember. Do you think it's the thicker mash or the extra sparge water that's making the difference?

loctones said:

Thanks, guys. EvilGnome6, I'd read that a thicker mash resulted in less efficiency. Maybe that was for no-sparge brewing--I don't quite remember. Do you think it's the thicker mash or the extra sparge water that's making the difference?

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I had read the same thing and was trying thinner and thinner mashes. My efficiency didn't improve.

I figured I'd give a thicker mash a try just to improve my lauter efficiency instead and it increased. After crunching the numbers I discovered that my conversion efficiency went up as well.

This has been my experience on my rig with my water. Your mileage may vary, of course.