understanding batch sparging / beer smith

Hi folks,

I've read the updated batch sparging article but I'm still left with questions.  I'm going to all grain here shortly so I'm trying to understand the process and beersmith so my first all grain goes without too many hitches.  

So, I am wanting to batch sparge. The mash profile I've chosen is: Single Infusion, Medium Body, Batch.   Looking at the brew steps:

>>>>>
name:              description:                                  step temp   time
mash in            Add 13.95 qt of water at 160.1 F     150.0 F        60 min
Batch sparge with 2 steps (1.70gal, 4.00gal) of 168.0 F water
<<<<<

What I understand is that I'm going to mash in at 13.95 qt of water @ 160f for 1 hour. My mash in temp is 150f.  What I'm not clear on is the second piece around batch sparging with beersmith.  Can you explain what these two steps represent? What does the 1.7 gal represent? What should I do? 4 gal?  both @ 168f water?  Does this second step supposed to represent "mashing out"?  Wouldn't the sparge temp be higher to get the grain bed @ 168?

thanks folks!

Jon

The 1.7 gal is to add, a light mix, vorlauf until clear, drain
then repeat with 4 gallons.

What I do is drain the mash tun, measure (estimate) the water needed to hit pre-boil volume, then add half that, vorlauf until clear, then drain.
Repeat using enough to hit preboil volume.

Neither step represents mash out.  BS is telling you to add 1.7 gallons of water and then vorlauf, lauter.  Then, add 4 more gallons of sparge water and vorlauf and lauter. 

A mash out isn't necessary with batch sparging because if you add your sparge water and let it sit for several minutes this effectively does the mash out. 

I only do one sparge step since I have a large cooler and can handle the volume.

Mark

You can click the option to drain the mash tun before sparging in the mash profile. Although I trust BS calcs are correct, I always measure the amount of water in the kettle with a tape measure before my final sparging.
Also, Batch Sparging allows you to move quickly to boiling, raising the temperature. IMHO mashing out is not needed.