sparging

[skinfull]

Had differance of opinions with a mate, when he makes a 5 gal brew he sparges up to the 5 gal mark, i sparge upto the 4 gal mark can anyone on the forum tell me who is correct or does it not make any differance. s.s.

[Aleman]

A good point to start is to have the same volume of sparge liquor as your final brew length. SO 5 Gallon Brew 5 Gallons of sparge water. Of course the volume collected in the boiler will be greater, so that you can allow for losses to the hops and evaporation.

With time as you dial you system in you start to know just how much is lost to hops, evaporation, dead spots etc, and can tailor the amount of sparge liquor to take that into account

[Jim]

One reason for sparging less is to avoid extracting tannins from the grain husks in the latter stages of the sparge. The danger is that the pH of the grains rises (becomes less acidic) as the sugars are removed, and this apparently increases tannin extraction.

The best way to judge when to stop is by checking the pH of the runnings - you should stop before the SG falls below 6 (some people stop at even higher gravities, but the efficiency of extraction falls if you do this). A simpler method is just to taste the runnings (dip your finger in the flow!) - you can soon tell when no more sugar is coming out, which is the point where you might as well stop anyway.

In practice I find I can collect the full length of a 5 gal brew without the runnings falling below 6.