New to all grain - questions

[UnderDogs]

I'm new to all grain...basically new to homebrewing but I'm jumping straight into all grain. I have all the equipment I just need to know the finally "detail" on amounts of water to use.

If someone can help out on this. Basically if you are making, say a 7.5 gallon batch, do you trying splitting that in half for each run off? So your first run off will equal 3.75 gallons and your second run off will equal 3.75 gallons?

Here is what I was thinking so correct me if I'm wrong.
7.5 Gal batch
11 lbs of grain
1.25 qt/lbs ratio
0.1 mash absorbtion qt/lbs ratio

Ok here is the math I have.
11 lbs x 1.25 qt/lbs = 13.75 qt
13.75 qt / 4 = 3.4375 gal

11 x .1 = 1.1 gal of mash absorbtion
3.4375 - 1.1 = 2.3375 gallons left

7.5 gal batch size / 2 = 3.75 gal per run off
3.75 - 2.3375 = 1.4125

Add 1.4125 for infusion to bring the 1st run off to 3.75 gallons.
Then add 3.75 gallons to the mash tun for the 2nd run off.

Is this correct or is there something I'm doing wrong?

[JXLT]

Maybe this link will be helpful.
http://www.howtobrew.com/section3/chapter18-4.html

[Lerxst]

If someone can help out on this. Basically if you are making, say a 7.5 gallon batch, do you trying splitting that in half for each run off? So your first run off will equal 3.75 gallons and your second run off will equal 3.75 gallons?

I like to look at it from the top view: If you want to collect 7.5 gallons pre-boil, your total volume (or total amount of water required) would be 7.5 gallons + water absorbed by grain + dead space volume.

Total volume - mash volume (which in your case is 1.25q/lb) = total sparge volume.

You can conduct your sparge however you want...mash out or no mash out, single sparge or multiple sparges. The important part is that all comes out of the total sparge volume accordingly. If you change your mash ratio, it just changes the resulting sparge volume. You can also find your dead space volume by filling your tun with a known quantity of water, drain and see how much you collect; the difference is your dead space.

This page helped me put the math together:
http://hbd.org/cascade/dennybrew/

So with your numbers
7.5 Gal batch
11 lbs of grain
1.25 qt/lbs ratio
0.1 mash absorbtion qt/lbs ratio

7.5 + (11*.1) + dead space unknown = 8.1 gallons total volume
(11 *1.25)/4 = 3.44 gallons mash volume
8.1-3.44 = 4.66 gallons required for sparge

if you want to do two batch sparges, split 4.66 in half
if you want to mash out with a gallon then sparge: 4.66-1=3.66 total sparge volume

[Joos]

Don't worry so much dude, or you'll probably not have a good brew day Especially if your just getting into it.Like was already said, there are different ways to get to the same volume. If your off then your off. You'll still make beer!

[ohiobrewtus]

Grab an evaluation copy of BeerSmith and go to town. It will tell you everything that you need to know.

[Lerxst]

Grab an evaluation copy of BeerSmith and go to town. It will tell you everything that you need to know.

Don't get me wrong (and I'm not saying this is what you intended)...

Software is a great tool but if you don't understand the process, you're only as good a brewer as your software.

[UnderDogs]

Yeah the software is asking for Dead Space and all this other stuff that I don't have time right now to figure out so I think I'm just going to not worry about it so much at the beginning and just have fun with it. I have so good info so I think I will be able to get through my first batch.

Like Joos said above "Don't worry so much... you'll still make beer." That sounds good to me.

[UnderDogs]

thanks k4df4l for the info. If I'm doing 5 gallon batch then the total gallons would be 6.1 and the sparge would be 2.66 for this example.

[Lerxst]

Don't forget that you want more pre-boil volume than your post boil 5 gallons to compensate for evaporation and trub loss.

[BlindLemonLars]

This is one of those instances where everybody is right!

Definitely don't stress out about the exact volumes right now. Just get brewing and do what it takes to achieve your mash temp & ratio, and get to your pre-boil volume. If you have to fudge a little to get there, it's really not a problem.

OTOH, definitely download Beersmith and start experimenting with it. Just getting it setup for your gear will give you a better grasp of your equipment and the brewing process. As you progress, you'll find it an invaluable tool.