Sparging question

How to know how much sparge water is needed to rinse the grains?.
Lets say i have 12 lbs. of grain,after i mash how will i know how much sparge water to use.IS it just an estimate ?

Depends on your strike amount.

Easiest method is to use a calculator of some sort.
here are some good online tools
TastyBrew.com | Homebrewing Calculators

You've gotta work backwards. This is where software really comes in handy.

Pre-boil volume = final volume + boil-off + absorbtion by hops
Pre-boil volume = strike volume + sparge water - absorbtion by grain - MLT dead space

You usually lose about .1 gal / lb of grain. You can solve the equation from there for how much sparge water you'll need to reach your pre-boil volume.

They used to just rinse until the wort was no longer sweet. Really!

BargainFittings said:

Depends on your strike amount.

Easiest method is to use a calculator of some sort.
here are some good online tools
TastyBrew.com | Homebrewing Calculators

Click to expand...

Yea i know,the best thing is to use the calc. ,but i am not quite sure what data to enter,for example on that calc u gave me link for:

Target Values

Grain Weight --- Weight of grain of course

(lbs) Absorption Factor -Must be the grain absorption factor?

Recipe Volume---- I guess beer u end up with after fermentation
(gallons)
Grain Displacement Factor --!-??
Recipe Gravity----- I belive its OG
(1.xxx) Wort Lost to Dead Space---- ???
(gallons)
Desired Kettle Volume---Like drained wort after the mashing you want to have in the kettle?
(gallons)

I've used this site and it has been very accurate.

All About Beer: Homebrewing (Water)

It's just what you need to reach your desired boil volume after the first runnings. You could measure it after the first running with a spoon marked out in gallons. I prefer to sit down and do the math. Basically it's your boil volume minus the watter you put in the mash plus .12 gallons per pound of grain for absorption plus dead space. If you fly sparge you just stop when you get there. Batch sparging works best (I mean most efficiently) with runoffs close to the same amount.

Thanx guys for info.Now i know how to calc. sparge water.
But how to know how much beer you will end up with in the beginning .
Lets say 40 punds of grain will result in how many gallons of beer .
Is the general guideline that 1kg grain malt gives around 5 l of beer?

No, it's about OG and efficiency. You get one gallon at ~1.030 from one pound. (37 PPG at 80%)