Batch sparging is an old method that is undergoing a revival in homebrewing. In batch sparging, wort is drained from the tun in steps, followed by the addition of more hot water. Originally, a brewer would drain off the First Running and brew a high gravity barley wine from that wort. More water was added and a second batch of wort drained. This was used to make an ordinary beer. The third, and possible fourth, runnings were used for making small beers.
A brewer might combine all of the runnings into a single batch. This is what most homebrewers do today.
For a homebrewer there are several advantages in batch sparging:
1. It eliminates the need to closely monitor sparge flow.
2. Channeling, stuck sparges and problems associates with shallow grain beds are reduced.
3. Temperature control is less critical, since each addition of water is large.
4. It can be done more quickly, both because of the large amount of water in each addition and the stirring, which increases the exposure of sugars to the hot water.
Batch sparging has a few disadvantages as well:
1. It requires more free space in the tun, so the mash can be stirred after each water addition.
2. The bed must be resettled after each addition.
3. Efficiency can suffer if the conversion has not completed before draining the First Runnings or the mash is not stirred and settled before each run.
The simplest way to batch sparge is to add the mash-out water, if desired, then drain the wort from your mash tun. Add approximately 1/2 of your sparge water (the total amount of sparge water used is the same as for fly sparging). Stir the mash gently for 10 minutes, resettle, drain and repeat.