Mashout V's No Mashout = ? Efficiency

[cdbrown]

I'm not quite understanding the process -
At the end of the mash, you drain your first runnings to the kettle and begin to fire it up
While the kettle is warming you add half your sparge water at 90c which increases grain bed temp, effectively doing a mash out and sparge in the one step
Do you then fully drain to the kettle and add the 2nd half of the sparge? Or are you adding the 2nd lot of sparge while draining the first?

Ross seems to drain the sparge quickly, but when I've done a fast drain it just causes channeling in the bed and efficiencies drop. I'd love to be able to knock 30mins off the brew (takes about 15-20mins to get to mash out using the HERMS + some time to recirc at the mash out temp).

 

[argon]

This is how i do it;
- Drain tun to kettle on full
- Fire up burner on low to heat above 80C
- Batch Sparge 1 - add 90C water to mash tun and stir
- Wait 5 mins
- Vorlauf
- Wait 5 mins
- Drain tun to kettle on full
- Burner on full
- Batch Sparge 2 - add 90C water to mash tun and stir
- Wait 5 mins
- Vorlauf
- Wait 5 mins
- Drain tun to kettle on full
By the time all liquor is in kettle it's coming up to boil

 

[felten]

I thought it didn't matter if you get channeling when you are batch sparging, as once you stir everything up, the liquid is as saturated with sugars as its going to get.