Fly Sparge Question

When I am finished fly sparging, should I still have water above the grain bed? Beersmith calculations give me just enough sparge water to let it drain through and leave the mash dry. So, is that okay or should I adjust my sparge water volume? I hope this is not to much of a noob question...Thanks!

you should sparge until your pre boil volume is reached.

That's not an answer to the question. You keep the water above the grain bed until you've added all the water that you've calculated you'll need. At that point, you drain the bed dry. That's how I've done it anyway. Wouldn't want to scoop out all that extra water after the lauter is done.

If your calculations are perfect you will run out of water as you hit your pre boil volume. Any left over water in the tun and u are leaving some sugary wort behind. You can drain it and boil longer then needed to get down to the volume you need but that another story.

I agree with lespaul23. We've been using BeerSmith for years and have always fly sparged. Always hit preboil volume and gravity. BeerSmith is a great program....Simie

There are two trains of thought on this.
Keep sparging until you get your proboil, maintaining your 1" water on top. Pro: keeps grainbed fluid and compacts the lower section less. Con: Uses more water that you throw away.
Calculate sparge volume so that you reach preboil volume just before running completely dry. Pro: uses less water Con: Could be less efficient if you miss calculate requiring a water topup later. Grainbed can collapse and compress halting runoff.

I tend to compromise. I calculate so that I'll leave about 2 gallons in the tun. That means the top half does dry out, but the area near the false bottom is still relatively fluid.

Nice, I was worried I was doing it wrong, thanks for the responses!