New to all grain - questions

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?

Check out Bobby's very helpful PDF here: http://www.suebob.com/brew/Bobby_M all grain primer.pdf

Yes, you're right. There are lots of ways to allocate sparge water (Bobby M. advocates no-mash-out-double-batch-sparge, which is different from the method you're using), but if you're doing the Denny Conn method, then you're absolutely right on.

Either way you choose to skin the cat...the thing that matters most to me is that on my last sparge, I will just check the kettle and estimate how much more I need to reach my preboil volume, and that amount will be my last sparge.

Simply put...sparge to fill the kettle to the proper volume...all these calculations...oh my head starts to hurt!

I also do the Bobby M...no mash out double batch sparge...basicly you just drain the initial mash, and then split the sparge in two...easy peasy.

So it wouldn't matter if you were doing a 8 gallon boil and you did a first run of 6 gallons and a second run of 2 gallons, or the other way around?

It doesn't case the wort to be more "lighter" or "heavier"? Again I'm new at this...

UnderDogs said:

So it wouldn't matter if you were doing a 8 gallon boil and you did a first run of 6 gallons and a second run of 2 gallons, or the other way around?

It doesn't case the wort to be more "lighter" or "heavier"? Again I'm new at this...

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Not quite. You want the mash (initial addition of water) to be at a set ratio, typically around 1.25 to 1.5 quarts per pound of grain. You then want the sparge volume to be enough to reach the desired pre-boil volume. It's the volume of sparge water that can be split any way you want.

The thickness of the mash (water to grain ratio) does have an effect on the body of the beer, in a similar way that temperature does. A thicker mash, and/or higher mash temperatures result in more unfermentable sugars, and a fuller body. Thinner mash and/or lower temperatures produce highly fermentable sugars, and a thinner body.

JuanMoore said:

Not quite. You want the mash (initial addition of water) to be at a set ratio, typically around 1.25 to 1.5 quarts per pound of grain. You then want to sparge volume to be enough to reach the desired pre-boil volume. It's the volume of sparge water that can be split any way you want.

The thickness of the mash (water to grain ratio) does have an effect on the body of the beer, in a similar way that temperature does. A thicker mash, and/or higher mash temperatures result in more unfermentable sugars, and a fuller body. Thinner mash and/or lower temperatures produce highly fermentable sugars, and a thinner body.

Click to expand...

OP, the idea is to end up with the correct amount of pre-boil wort at the right gravity to hit your recipe targets for volume and gravity into the fermenter. I usually dough in with 1.5 quarts / lb or so, but I've gona as high as 3 qts/lb with no problems, although at 3 qts/lb, it's essentially a no-sparge brew.

On a typical brewday, to get the sparge volumes, I look at the volume of my first runnings, subtract from my usual 7 gallon preboil volume, split the difference in half, and then sparge twice with whatever amount of water I need.

As for mash thickness and effects on fermentability, I'm not so sure that applies at homebrewing scales. For reference, check out Kaiser's research at http://braukaiser.com/wiki/index.ph...ity_and_efficiency_in_single_infusion_mashing

Reproduced below is a chart of Kaiser's results of attenuation limits as a function of mash thickness in a fast ferment test. The results from thick and thin mashes are practically superimposed.

Just to clarify, your math looks good, and should work fine. What I'm trying to say is that you can split your mash-out/sparge water in any way you want to. You could do the 1.4 gal mash-out and then 3.75 gal sparge like you described, or skip the mash-out and sparge 5.15 gal, or skip the mash-out and do two 2.57 gal sparges, or do a 2.57 gal mash-out and a 2.57 gal sparge. The main thing is to find a system that works for you, and then stick with it so that you can repeat (and therefore predict) your efficiency.

What's you initially proposed is absolutely fine.