Initial water volume

[8gallonalchemy]

So, super noob question, but how do I know exactly how much starting water a recipe calls for. It's pretty clear that a 5-gallon batch is going to require more than 5 gallons to begin with, but is there a standard formula for how much water per pound of grain one should use?

 

[camonick]

It all depends on what kind of brewing process you're using.
https://www.brewersfriend.com/2010/06/12/water-volume-management-in-all-grain-brewing/

 

[IslandLizard]

I often use this small, handy calculator (using a regular mash tun and 2 batch sparges):
Brew365

Using a converted cooler (regular, single infusion mashes) or my kettle (step mashes), I prefer to mash at a water:grain ratio of 1.5 qts/pound. Easy to stir, good conversion in an hour and a little easier to keep the temp. Batch sparge 2x with half the sparge water each. Mash efficiency 80-85%.

Now for BIAB, many do full volume boils, or reserve a gallon or 2 to sparge the bag, but same principles apply.

 

[Kent88]

The quick-and-dirty answer:
water needed = (recipes stated pre-boil volume) + (water lost due to grain absorbing) + (water lost to your system)

Pre-boil volume = (final volume) + (boil off)
->You may need to overshoot your desired final volume if you're making a massively hoppy beer.

Can someone help me with the amount of water grain typically absorbs? Anything I have forgotten?

The long answer:

A lot of recipes should tell you what pre-boil volume you need, and some even tell you what water:grist ratio is recommended to begin mashing with. There can be some interesting factors at play. You'll really need to consider when to stop sparging, and with that it's actually best to go by gravity.

I like to mash in at a water:grist ratio of about 1.3quart/pound. I sparge until the wort I collect has a gravity reading of about 1.012. That should work for most beers. If you are making a very light, low gravity, low alcohol beer than you might have to dilute the wort after sparging. If you're making a strong, high gravity beer then you'll probably end up with a high pre-boil volume and you'll need to boil for a very long time or look at other tricks like using extract or parti-gyle.

 

[Rackrunner]

Can someone help me with the amount of water grain typically absorbs? Anything I have forgotten?

I've always used 0.1 Gal / LB of grain, though I've heard lower numbers if you BIAB and squeeze. I also use a similar number (0.75 G / oz) for pellet hop absorption, but again this depends if you're just chucking them in, using a spider/bag and squeezing a little etc)

Like others have mentioned, the answer really depends on your brewing setup/process. I try to calculate backwards from my end result going into the keg to make sure I've got a good fill with not too much waste. As a rough example, if I:

Target 5 G into the keg
+0.5 G for dry hop absorption + fermenter losses = 5.5 G needed in the fermenter
5.5 Gal + 0.25 G cooling loss (shrinkage!) + 0.5 G hop / trub / chiller losses = 6.25 G needed for my post-boil volume

Pre-boil volume is essentially your post-boil volume + your boil off rate (and possibly + losses if transferring). If the recipe calls for a 60 min boil, and I boil off 0.75 G / hour I get:
6.25 G + 0.75 G = 7.0 G pre-boil target

From there I work in the grain absorption (lets say it's 10lb of grains @ 0.1 Gal / LB for easy math)
7 G + 1 G absorption = 8 G total water needed

For a 10 lb grain bill, if you target a mash thickness of 1.3 quarts / LB, it's 13 quarts or 3.25 G strike water
Total water (8 G) - Strike water (3.25 G) = 4.75 G sparge water

Almost all of these variables (boil rates, absorption, losses etc) heavily depend on the process and equipment you're using to dial in your numbers. I agree with IslandLizard, the calculators are your friends especially once you know what your typical losses and rates are.

Hope this helps!

 

[Silver_Is_Money]

Beginning water volume (Gal.) = Projected fermenter Wort volume (Gal.) + (0.12 Gal. * Lbs. of grain) + Boil loss (Gal.) + System losses (Gal.)

For the case of a desired ending of 5.5 gallons in the fermenter, and for 11 Lbs. of grain, a one hour boil loss of 0.8 gal., a one hour boil, and equipment losses totaling to 0.25 Gal. this becomes:

Beginning water volume (Gal.) = 5.5 + (0.12 * 11) + 0.8 + 0.25
Beginning water volume = 7.87 Gal.

** Ballpark 5.5 gallons in the fermenter will yield a final beer volume of about 5 gallons.

 

[balrog]

So, super noob question, but how do I know exactly how much starting water a recipe calls for. It's pretty clear that a 5-gallon batch is going to require more than 5 gallons to begin with, but is there a standard formula for how much water per pound of grain one should use?

If you're extract brewing, you get one answer.
If you're all grain, then
If you're doing 3 vessel, you get a different answer
else if you're BIAB, I say go with Priceless, or BrewersFriend, each good calcs that will give you water requirements

Oh, endif.

 

[kh54s10]

The calculators will get you in the ballpark but every system is different. Boil off in particular. It depends on how vigorous the boil, geometry of your pot and to a lesser extent atmospheric conditions - temperature, humidity, altitude etc. You need to record your volumes and adjust until you have it fine tuned (somewhat).