When to begin draining HLT when fly sparging

[jack13]

When fly sparging, after vorlaufing, should I run off any wort from the mash tun before I begin to drain the HLT, or just start that HLT going right away?

I've read I should drain the mash tun until there's an inch of water above the grain bed, but in all the times I've batch sparged, I've never seen the grain bed below the surface of the water at all--it seems to just float the entire time it's draining. I've only actually seen water above the grain bed (i.e., the grain bed seeming to be below the water) after I started fly sparging, and this only occurs a couple minutes AFTER the HLT starts to drain.

In other words, the "begin draining HLT when there's an inch of water above the grain bed" rule doesn't seem to work for me...so any thoughts on when I should start the HLT draining?

 

[Qhrumphf]

If you're adding water for a batch sparge, stirring, and immediately running off, the grain bed may not have resettled back down yet. It should settle during vorlauf (always does for me) but if not give it a few minutes before vorlaufing. I always have the grain bed settled to the bottom whether batch or fly sparging. Always.

To answer the initial question, yes, I start running off the mash slowly into the kettle, dial it down to barely above a trickle, and then start running in sparge water at the same rate when I'm 1-2" above the grain bed.