How much water to start with?

[daphatgrant]

Hello HBT, I’ve got a couple questions

When figuring out how much water I need when beginning my brew day I need some help. I’ve looked around and it looks like using 3 formulas and adding them together might be a good starting point?.

For mashing:
X lbs grain * 1.1 qts water /4 = X gal water

For Sparging:
X lbs grain * .5 = x gal water

For Boil-Off:
1.5 gal water for 60 min boil, 2 gal water for 90 min boil


So if I were to have 10lbs of grain and a 60min boil I’d have;

10 * 1.1 /4 = 2.75 gal for mashing
+
10 * .5 = 5 gal for sparging.
+
1.5 gal for boil-off
=
9.25gal water.


Does this sound reasonable? I know that this isn’t including dead space or line loss or absorption by hops.

 

[mongoose33]

I think you're high on the total amounts.

When I was doing a mash tun w/ sparge, my typical water volume was 8 gallons, maybe 8.25 if I had a large grain bill.

When I did BIAB, typically 7.25 gallons.

Currently I do a mash tun w/ recirculation and expect something like 10 percent losses to various things, and I'll start with 8.25 gallons.

For yours, just split 4 gallons and 4 gallons, mash and sparge, and you'll be fine. You can then tweak as you like once you see exactly what you get.

 

[wilserbrewer]

Mash w 4 gallons and measure your first runoff...
Subtract that amount from your pre boil volume and you have your sparge amount...
Don’t over complicate

 

[CascadesBrewer]

You can use software to figure this out...follow a simple process...or do it manually.

First, decide what value you want to drive your volume. For me, this is either the amount into the fermenter or the amount into packaging.

An example for me might be (in gallons):

• 7.55 : volume mash water
  • - 0.8 gal absorption
• 6.75 : volume pre-boil
  • - 1.0 gal/hr boil off
• 5.75 : volume post-boil
  • - 0.25 trub loss in kettle
• 5.5 : volume into fermenter
  • - 0.5 loss in fermenter
• 5.0 : volume into keg

Also note that when measuring volumes, the expansion and shrinkage based on temp matters. I really need to measure about 7.0 gals at the start of the boil to account for the 0.25 gal difference between 210F water and 70F water.

 

[Smellyglove]

You can use software to figure this out...follow a simple process...or do it manually.

First, decide what value you want to drive your volume. For me, this is either the amount into the fermenter or the amount into packaging.

An example for me might be (in gallons):

• 7.55 : volume mash water
  • - 0.8 gal absorption
• 6.75 : volume pre-boil
  • - 1.0 gal/hr boil off
• 5.75 : volume post-boil
  • - 0.25 trub loss in kettle
• 5.5 : volume into fermenter
  • - 0.5 loss in fermenter
• 5.0 : volume into keg

Also note that when measuring volumes, the expansion and shrinkage based on temp matters. I really need to measure about 7.0 gals at the start of the boil to account for the 0.25 gal difference between 210F water and 70F water.

Unless I got your post wrong, you're omitting the deadspace when it comes to grains needed to compensate for the deadspace to keep your wort at the target volume and OG. More losses means you need to brew more wort, meaning more grains, which leads to more water absorption, and more water.

For instance, if you have 1L of losses somewhere, you can't add 1L of water to compensate, your SG would be lower than target.

 

[CascadesBrewer]

Unless I got your post wrong, you're omitting the deadspace when it comes to grains needed to compensate for the deadspace to keep your wort at the target volume and OG. More losses means you need to brew more wort, meaning more grains, which leads to more water absorption, and more water.

For instance, if you have 1L of losses somewhere, you can't add 1L of water to compensate, your SG would be lower than target.

I don't have any deadspace in my system (doing BIAB) but, yeah, that could be another source of loss to account for (in mash tun, in counter flow chiller, etc.).

 

[acidrain]

What Wilserbrewer said.
Are you guessing at your boil-off rate? That is an exact volume you need to know.