Can you check this for us... (sparge water)

So we have a recipe here that we are having issues with deciding on how much sparge water to use...
12lbs. 4oz. Golden Promise
6oz. Caramel 60
We are going with 4gallons for our mash...how much typically do you use when you start to sparge?
How can you increase your efficiency since for some reason we are only getting half of what we put into our tun...meaning for 4 gallons of water we seem to be getting just over 2 gallons...is that right?

Pugs13 said:

So we have a recipe here that we are having issues with deciding on how much sparge water to use...
12lbs. 4oz. Golden Promise
6oz. Caramel 60
We are going with 4gallons for our mash...how much typically do you use when you start to sparge?
How can you increase your efficiency since for some reason we are only getting half of what we put into our tun...meaning for 4 gallons of water we seem to be getting just over 2 gallons...is that right?

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You have to remember that the grain is going to act like a sponge when you add the water. During your mash, the grain absorbs the water that you enter into it. Only the wtaer that is cannot hold onto will pass through to your brew kettle (along with all of the delicious converted sugars).

Good news is that makes calculating your sparge water volume fairly simple. If you can measure your first runnings, and say it's 2 gallons, you'll need to sparge with approximately 4.5 gallons to achieve your target preboil volume of 6.5 gallons. This is so because your grain has reached maximum absorbancy.

Hope that helps.

You will absorb 0.19g. of water per pound of grain, sometimes less, depending on your method. So you're coming out right on the 2g. of first-runnings, no worries there.

If you're coming out with 2g. first runnings and looking for 5g. in the FV, you'll need about 4.5g. of sparge water to make 6.5 in the BK, boil off a gallon probably, and then trub/hop losses would bring it close to 5g in the fermenter. This is ballparking and based on a 60m boil with 1g/hr boiloff rate.

tre9er said:

You will absorb 0.19g. of water per pound of grain, sometimes less, depending on your method. So you're coming out right on the 2g. of first-runnings, no worries there.

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In my experience it's been more like 0.13 gallons per pound when using a dedicated mash tun, and yesterday when doing BIAB and "squeezing" the bag I ended up with more like 0.1 gallons per pound absorption.

According to BeerSmith and Promash, grain absorbs 0.12 US gallons per lb. (very close to 0.13).
You will also probably have some dead space in the MLT. Add the dead space to the absorption, and (if your system is anything like mine), a tad over 2 gallons collected looks to be about right.

-a.

Man you guys are awesome! This is super helpful and saves a lot of time of experimenting. No wonder we did not hit our FG last time! We were WAY off and made a huge mistake of overly topping off with water...I know dumb move...I read somewhere for a nice sparge you can also get a calculatation approximately 1/2g. per lbs. of grain you are using. I however like all your thoughts on see where you are at after your first runnings. Then calculate how much to put in to get to about 6.5g. or even 6g. Thanks again guys!

weirdboy said:

In my experience it's been more like 0.13 gallons per pound when using a dedicated mash tun, and yesterday when doing BIAB and "squeezing" the bag I ended up with more like 0.1 gallons per pound absorption.

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I'm using .1 for BIAB w/bag squeeze, too. I'm not boiling off as much water, either, so I have to halve that figure as I've been high on my recent recipes.