Calculating water volumes

[Photomanliny]

OK I am just checking to see if I am doing this correctly (or at least in a way that will work).

I am making (and planning ingredients for) six gallon batches with the hope of getting like 5.5 gallons into the primary and giving up .5 gallons to the bottom the brew pot for "things we do not need." If I get a little less into the carboy, so be it. As long as it is 5+ gallons.

Since I lose about .6 Gallon (77 oz) to the boil, I need to start with 6.6 gallons in the brew kettle (or so I believe). So in order to achieve that I assumed the following:

Sparge Water Volume = Boil Volume - Mash Water + Mash Tun Dead Space + Hot Liquor Tank Dead Space + Grain Absorbtion.

Lets say I am making a "10 pounds of grain" batch then and that I use 1.25 quarts of per pound for single infusion mash (no mash out). Lets further assume that I lose about 64 oz of liquid at the bottom of both the mash tun and the hot liquor tank. I would get the following (in ounces):

Sparge Water = 845 (boil volume)- 400 (mash water) + 64 (dead space) + 64 (dead space) + 128 (grain absorbtion)

Sparge Water = 701 oz (21.91 qt) round to 22 qts or 5.5 Gallons

I would then fly sparge until the sparge water runs out and then the mash/lauter tun emptys into the kettle.

Will this method work? Am I ok here?

Should I just go with the Papazian method of sparging with half a quart per pound (hence 160 + 64 = 224 oz) and then add water to the boil?

Thanks in advance for replies and help. It is appreciated.

 

[Homercidal]

People do different things. Lots of people who fly sparge, focus on the mash volumes and then simply sparge until they get their boil volume, or until the residual sugar in the lauter is nil, then top up with water to reach their boil volume.

I batch sparge, so I generally measure my mash and sparge volumes ahead of time, and hope to hit them.

At any rate, I recommend checking your gravity going into the boil kettle (mix it well to be sure you get an accurate reading) before topping up. I think it's better to have more/less beer at the correct gravity than the exact amount with a higher/lower gravity.

With that reading you can know now much more water to add, or how long to adjust the boil to reach your desired gravity. A small bit of extract can help you adjust higher without needing an extended boil.

 

[stjackson]

I plan to refine this process, but, on my first AG batch, I calculated how much mash water I needed, how much I would lose to grain absorption, how much I would lost to dead space and how much I would need in my pot pre-boil. Whatever the difference was between what I would gain/lose in the mash and what I needed pre-boil I generously rounded up and put in for sparge water. I ended up with a good bit left over, but I'd rather have a bit too much than not have enough.

 

[ajf]

I think you are probably going to end up a little bit short on your volumes with the water.
Your calculations are based on 1 gallon water weighing 8 lbs. 1 US gallon water actually weighs 8.345404 lbs.
I do what Homercidal suggested. i.e. sparge until I have got my required volume, or until the gravity of the runnings drops to 1.010 (whichever comes first). If the gravity drops to 1.010 before I have collected the required volume, (which often happens with low gravity brews), I just add water to the wort to reach the required volume.
I also agree with stjackson. It's better to have too much sparge water than too little. I usually prepare about 1 gallon more than the estimated sparge water. If I don't need it for sparging, it gets used for cleaning up.
Couple of other things:

• if you use whole hops, you may want to consider hop absorption as a source of loss.
• I found that adding a mash out prior to the fly sparge increased my efficiency by 10% with no adverse consequences.

-a.