While full-volume variations, always increase your basic VIF and VIP, as stated above, there is also always, a compromise, when compared to full-volume brewing.
What hasn't been mentioned above, is that there are also limits as to how much you can employ any full-volume variation.
The Compromises of Sparging
Should you choose to employ a sparge, there will be no cost to you in quality or ingredients, however, you will incur equipment, time and labour costs. You will always, need at least one more vessel and, nearly always, one more heat source.
For the stove-top brewer, deciding to sparge, the easiest way is to have quite a large saucepan or pot. Some, or all, of the water held back from the mash, can be heated in that pot to at least mash-out temperature, and, at the end of the mash, the bag of mashed grains can then be transferred to the second pot. After agitating the mashed grains, the bag can then be pulled and squeezed. The runnings from the bag should be then added to the sweet liquor in the main pot, the kettle, which will then be brought to the boil.
Volume Limits to Sparging
Obviously, we can't have a kettle and then sparge an indefinite amount of water in a second vessel. As a silly example, with a 19L kettle, we couldn't sparge in a second pot, no matter it's size, with 19L of water as our runnings when poured into the main kettle would overflow it.
So, what are our limits?
In the second post of this thread, you had to play a game of 'twenty questions,' to determine your VIF and VIP. All full-volume variations require you to play that same game. In that second post, though, you were given a number to start playing the game with (half of your kettle capacity). We can do the same with sparging.
With sparging, assuming you have mashed with as much water you can comfortably fit in your kettle, at the end of the mash, when you pull the bag, there will be some extra space available now, in the kettle.
The picture in the last post, in Section K, shows a Mash Volume of 16.99L and a Volume into Boil (VIB) of 14.07L. What this means, is that, if you had full-volume brewed, after pulling the bag, you would have an extra 2.92L (16.99-14.07), safely available in your kettle. This Mash Volume minus VIB number is a good number to plug into Section W, if you choose to sparge. Here's a pic of The BIABacus, after I input 2.92L to 'Water Used in a Sparge.' See how the Mash Volume has dropped from 16.99L to 14.01L?
This means I can now increase my 'Desired Volume into Fermentor (VIF),' a little. Increase it until you see a red warning appear above Section B.
You'll find that you can increase your desired VIF from 8.1L to about 10.0L. Here's the file... The BIABacus will throw you a warning if it looks like you are sparging too much. You'll see one in the file at the bottom of the file above. Dropping the amount from 2.9L to 2.8L will get rid of that warning but trigger others. Getting rid of all warnings involves a game of 'twenty questions,' by lowering gradually your desired VIF and/or 'Water Used in a Sparge.' The game can be quite endless, if you play it too tightly, so, be sensible.
Sparging allows you to increase your VIF and VIP, with no drop in quality, but, at the cost of increased equipment, time and labour. The higher the original gravity of the beer, the higher rewards/versus cost of sparging, but, if your kettle allows full-volume brewing on a high gravity beer, then, sparging will cost you without producing any reward.
You do not have the required permissions to view the files attached to this post.