Sparging for extract/spec. grain brewers

I've come across a few receipes for extract/steeping grain brewers that say to sparge the steeped grain bag with a 1/2 gallon of ~170F water after you have rung the water out of the grain bag. What exactly does this accomplish?

Is it basically getting a little more fermentable sugar out of the grains aka raising the OG ever so slightly? Are there other benefits of sparging a grain bag for extract/steeping grain brewers?

Sparging your specialty grains gets a little more sugar and flavors out of the grains, not much though. Since I generally have five gallons of water in the kettle, I just let the bag drain & then dip it back into the kettle once or twice.

Sparging, or rinsing, is done to wash the sugar off of the grains.

Also, you're not supposed to "wring out" the grain bag because it can cause tannins to get into your brew effecting the flavor.

As hb99 mentions, you probably shouldn't wringe out the grains. You're more then likely doing more harm then good by doing this.

When I brewed extract + grain, after they had their time to steep, I'd lift the bag almost all the way out of the water, and then slowly pour a few quarts of hot water over it to rinse the grain a bit, and then waited for it wind down to a slow drip.

Now, how benificial that is is probably negligable, but if it makes you feel better then I'd say to go for it.

It's got nothing to do with fermentable sugars, but with taste and (depending on which specialty grains you are using) colour.

I steep mine in a fairly small amount of water (a few litres), but then give them a good rinse with about another litre of water. The runoff is quite substantial in both colour and taste, so I'm positive that I get more out of my specialty grains like this.