estimating water requirements

[twd000]

I am planning a Black IPA all grain - I have 12.5 lbs of grain

I would like to end up with 6 gallons pre-boil

Ray Daniel's chart estimates I will lose 2.5 gallon to the grain bed. Beersmith shows 1.5 gallons. Which is more realistic?

At 1.25 quarts per pound grain, I will mash with 3.9 gallons (plus grain bed losses)

At 1/2 gallon per pound grain, I will sparge with 6.25 gallons (assuming that the grain bed is saturated and will not absorb any more water)

Does this sound like a lot of water? Beersmith shows 8+ gallons of water, but using my formulas I'm getting some closer to 12, which seems like a lot

 

[Clonefarmer]

I am planning a Black IPA all grain - I have 12.5 lbs of grain

I would like to end up with 6 gallons pre-boil

Ray Daniel's chart estimates I will lose 2.5 gallon to the grain bed. Beersmith shows 1.5 gallons. Which is more realistic?

At 1.25 quarts per pound grain, I will mash with 3.9 gallons (plus grain bed losses)

At 1/2 gallon per pound grain, I will sparge with 6.25 gallons (assuming that the grain bed is saturated and will not absorb any more water)

Does this sound like a lot of water? Beersmith shows 8+ gallons of water, but using my formulas I'm getting some closer to 12, which seems like a lot

I multiply the grain amount in pounds by .12 to get the absorption rate and it's usually pretty close.
Example: 12.5 x.12 = 1.5 gallons absorption

I get 3.9 for the strike as well. So I would subtract the absorption from the strike.
Example: 3.9 - 1.5 = 2.4 first running

You lose a little bit during sparge, but not much. So I would add your first running and your sparge to get your pre-boil.
Example: 2.4 + 6.25 = 8.65

This is the formula I use and it works well on my system.

 

[twd000]

I multiply the grain amount in pounds by .12 to get the absorption rate and it's usually pretty close.
Example: 12.5 x.12 = 1.5 gallons absorption

I get 3.9 for the strike as well. So I would subtract the absorption from the strike.
Example: 3.9 - 1.5 = 2.4 first running

You lose a little bit during sparge, but not much. So I would add your first running and your sparge to get your pre-boil.
Example: 2.4 + 6.25 = 8.65

This is the formula I use and it works well on my system.

interesting - I would have assumed you would add water to overcome grain bed absorption, rather than subtracting it as a loss

starting with 8.65 gallons pre-boil will yield way too much post-boil, so should I reduce the sparge amount so that I start with 6 gallons pre-boil?

 

[CPooley4]

I would recommend shooting to get half your boil volume from the mash and the other half from the sparge. This will maximize your efficiency for a batch sparge.

- 12.5 x .125 = 1.56 gallons absorbed by grain
- 6 gallons preboil / 2 = 3 gallons from mash and 3 gallons from sparge
- 3 + 1.56 = 4.56 gallons of mash water to be used
- 3 gallons of sparge water to be used (grain does not absorb anymore). Make sure to measure how much you got from your mash before you sparge. If you only got 2.75 gallons you'll want to use 3.25 for the sparge for example.
- That gives you a total of 6 gallons preboil wort.

Make sure to get a fine crush on your grains and make sure to drain that tun dry to get all the sugars you can. No sense in leaving any efficiency behind if you can avoid it.

Good luck.

cp

 

[Clonefarmer]

interesting - I would have assumed you would add water to overcome grain bed absorption, rather than subtracting it as a loss

starting with 8.65 gallons pre-boil will yield way too much post-boil, so should I reduce the sparge amount so that I start with 6 gallons pre-boil?

You can add water to the mash in order to get more first running, but you have to thin the mash to do so. If you want to keep a thick mash adjust your sparge amount instead.

 

[petep1980]

When I use .2 x grain I always have water leftover in my mash tun.

I'm going to try BeerTools .12x.

 

[jmf143]

Formulas are great in theory, but in your brewing world they are of limited use. Here's what you are going to experience -
You'll mash in with say, 1.25 qts per pound or so. Collect your first runnings and measure how much volume you collected. Sparge with about 1/2 of the difference between your desired total pre-boil volume and what you already collected. Collect your second runnings and measure the total of what you collected (1st & second runnings) and specific gravity of that collection. Calculate the amount of gravity points you've collected (volume in gallons x last 2 digits of your specific gravity). For example, you collected 4 gallons and your specific gravity is 1.068; your gravity points are 4x68 = 272. Compare that figure to the gravity points that you should have after boiling according to your recipe. Again for example, your recipe might say 5.25 gallons of 1.052; 5.25x52 = 270. This example shows that you have collected more than enough points, so you are done sparging. Use top off water to get to your pre-boil volume. If your collected points are way over what you need, you'll have to remove some wort and use top off water in its place. If you haven't collected enough gravity points you have to sparge some more, collect your 3rd runnings and repeat the calcs.

The formulas will get you close but only your actual results are what counts.