Any step-by-step walkthroughs on mash/sparge water calcs?

[GrumpyOldGit]

I'm pretty sure this has been covered somewhere but my jedi search powers are weak tonight...

Are there any detailed examples of how you calculate the water volumes for infusion, mash, and batch sparge?

I can easily get my head around Palmer's infusion calcs for 1, 2, and 3 step infusions, and my logic was to treat the mashout as the 2nd step of a 2-step infusion (step 1 - get grain to temp X, step 2 - get grain to 168, then drain out first runnings, then batch sparge twice...).

But, when I look at an all-in-one calculator like BrewToad it all goes to pot - I match some numbers but not all so I'm missing something. So, are there any steps out there to go through a single infusion with mashout followed by batch sparge with the calculations exposed?

 

[Natdavis777]

If you want to do it via math, you can figure how much wort you yield after a mash, which mine is usually 58-59% of the total mash volume. So if I mashed with (for the sake of simple math) 10 gal, I would get 5.8 to 5.9 gal back. Subtract that number from your desired pre-boil volume (we will say 15 gal total) and you end up with ~ 9 gal of sparge water. Again, you need to find out the % of return from your initial mash volume.

If you want to use a calculator instead, Brew365.com is a great source of water volumes, temps, and water:grist ratios. So is brewersfriend.

 

[JLeuck64]

I can help! It's really easy to figure out if you approach it from a mash in/batch sparge brew day style. One of the things I stumbled upon when looking thru Palmer's How to Brew was the efficiency you gain when trying to split the mash volume water versus batch sparge water into a 50/50 ratio. This ratio helps to max out on the sugar extraction from the grains and it's really easy to figure out. Here is an example, you can apply it to any recipe. Let's say you have 10lbs of grains in your recipe. Just do a little math and crunch the numbers for a mash ratio of 1.5 or 1.75qts or 2.0 qts per lb of grain to figure out how much water you need to mash in with. So with 10lbs of grains X 1.5 qts/lb of grains you end up needing 15 qts of H2O. Divide that by 4 qts per gallon equals 3.75 gallons needed for the mash. The grains we use in each recipe will absorb their weight in water, and water is 8.3lbs per gallon so we need to account for that. Just divide your 10lbs of grain by 8.3lbs/gallon and you get 1.2 gallons lost (due to absorption). We need to subtract that amount from the 3.75 gallons used to mash with... 3.75 - 1.2 = 2.55 gallons net. So in a perfect world you would expect to get 2.55 gallons to drain into your boil kettle after draining your mash tun. It really never works out that way because we all have some dead space that we need to account for but once you figure out what that amount is you just add it to your volume used for the mash in. So if you wanted to target a 6 gallon pre boil volume (I am assuming a 1 gallon loss during the boil here) we would need to sparge with another 3.45 gallons of water. It's interesting that the water needed to sparge with really just passes on through to the boil kettle. Since the grains have already absorbed their weight in water... the sparge just rinses any remaining sugars from the grains and that volume goes directly into the kettle. BUT... when you compare 2.55 gallons net from the first runnings to the 3.45 gallons needed to sparge with it's not a 50/50 split. Let's try again using 1.75qts/lb of grain. 10 X 1.75 = 17.5 qts divided by 4 equals 4.375 gallons. If you mash in with that volume you could expect to get 3.175 gallons from the 1st runnings. To reach your target volume of 6 gallons pre boil we'll need to sparge with 2.825 gallons. This still is not a 50/50 split but it is really close! I can see after a few of these calculations that what we are shooting for with this recipe is a net of about 3 gallons for the 1st runnings (plus the dead space in your mash tun). Then all we would need to do is spage with another 3 gallons to reach the target pre boil volume.

If you post up your recipe I would be happy to walk you through how to calculate it if you have trouble following the calculations above. Once I started doing these calculations during brew day my all grain brewing my efficiency numbers went way up
( ;

 

[doug293cz]

Let me start by saying that when batch sparging, there is no need to do a mash out. The purpose of a mash out is to quickly denature amylase enzymes to prevent the wort from becoming too fermentable during an extended fly sparge. With batch sparging, you can start to heat to boil (which will also denature the enzymes) as soon as you get some wort in your BK, and run off can be done quickly, so there is little time for extended enzyme action. You do need to insure that starch conversion has completed, or you may lose some conversion efficiency without a mash out. The effect of the mash out on efficiency is simply providing more mash time, which can be done without raising the temperature. Check for conversion efficiency using the method here.

Volume calculations are easiest to understand if you work backwards from the final volume, and then add all the losses that occur throughout the process.

Start with your desired volume for packaging (bottling or kegging), and then add the expected fermenter trub losses to get your starting fermenter volume. Amount of fermenter trub will depend on how much boil kettle trub you transfer to the fermenter, and is typically 10% to 15% of your packaging volume. So:

Target Fermenter Volume = Target Packaging Volume + Expected Fermenter Trub Volume​

Next determine your target post-boil volume which is just your target fermenter volume plus the volume of trub you expect to leave in the boil kettle.

Target Post-Boil Volume = Target Fermenter Volume + Expected Kettle Trub Volume​

Next determine your target pre-boil volume. For this you need to know your boil off rate in gal/hr and your boil time.

Target Pre-Boil Volume = Target Post-Boil Volume + Boil Off Rate [gal/hr] * Boil Time [hrs]​

Next determine your sparge water volume. As stated by a previous poster, efficiency is maximized when all the run offs are equal volume. Thus for a single batch sparge, the required volume is:

Sparge Water Volume = Target Pre-Boil Volume / 2​

Last determine your strike water volume. For this you need to know the volume that will be held in the grain (about 0.12 gal/lb), and the undrainable volume of your MLT.

Strike Volume = Sparge Volume + Grain Wt [lb] * 0.12 [gal/lb] + MLT Undrainable Volume [gal]​

That's all there is to it. Notice there is no need to worry about water to grain ratios for the strike volume.

Brew on

 

[henryred]

There is an app called sparge pal. And brew pal. I use sparge pal to let it do the math.

 

[GrumpyOldGit]

If you want to use a calculator instead, Brew365.com is a great source of water volumes, temps, and water:grist ratios. So is brewersfriend.

Thanks for the info on the sites.

 

[kh54s10]

It really is so much easier that all that calculation. Use 1.25 to 1.5 quarts per pound of grain for the mash. Heat plenty of sparge water. Drain the tun after the mash is done. Measure how much you collected. Then sparge with enough to get to the amount you need to account for your boil off rate.

For example. If I collect 3 gallons from the mash, I know I need just over 7 gallons for the boil so I would need just over 4 gallons for the sparge.

I usually split the sparge in two additions. That way after the first sparge I have a pretty accurate number for what I need in the second sparge. This leaves very little water in the spent grains making it lighter to carry to the compost pile. And it might also help with efficiency by not leaving wort in the tun.

 

[GrumpyOldGit]

If you post up your recipe I would be happy to walk you through how to calculate it if you have trouble following the calculations above.( ;

Thanks for the info and the offer. I'm looking at a simple Tripel recipe with 14lbs of Pilsner malt and 0.25lb of 20L Aromatic (it also has 2.5lbs of Candi syrup but I can add that to the kettle at the end). So, if I use Palmer's numbers for a single infusion with:
Grain Temp: 60
Single Mash: 149F
Ratio of 1qt/lb
7G/28qt boil
for 14.25lb of grain I get to strike with 14.25 quarts at temp of 167F. Let's say I loose 1qt due to the tun shape, and say 0.5qt/lb absorbed (so 1 + 7.125 = 8.125qt). So although I added 14.25 qts I only get 6.125qt out so would need to add 21.875 qt to get to 28.

However, if I use an initial ratio of 1.5qt/lb the strike is 21.375 quarts at temp of 161F. After I lose the 8.125qt I pull 13.125qt on first runnings and only have to add 14.875qt in the batch - which although not 50:50 is close enough to get a good extraction.

Is that about right?
(Also, if there isn't enough headspace in the tun to add 14 qts, should I just split it into multiple batches as long as the 1/2/3 batches add up to 14 qts?)

 

[GrumpyOldGit]

Let me start by saying that when batch sparging, there is no need to do a mash out.
...
Volume calculations are easiest to understand if you work backwards from the final volume, and then add all the losses that occur throughout the process.

Thanks for the note on not needing a mash out - and also thanks for adding 'why', that's always nice to know.

And thanks for the calcs - I ran through for the 14.25lb recipe above aiming for a 7G boil and the calcs dropped out that I should aim for a strike around 5.5G/22qt which is reassuringly close to the 5.3G/21qt I got long-hand from JLeuck64.

 

[doug293cz]

Thanks for the info and the offer. I'm looking at a simple Tripel recipe with 14lbs of Pilsner malt and 0.25lb of 20L Aromatic (it also has 2.5lbs of Candi syrup but I can add that to the kettle at the end). So, if I use Palmer's numbers for a single infusion with:
Grain Temp: 60
Single Mash: 149F
Ratio of 1qt/lb
7G/28qt boil
for 14.25lb of grain I get to strike with 14.25 quarts at temp of 167F. Let's say I loose 1qt due to the tun shape, and say 0.5qt/lb absorbed (so 1 + 7.125 = 8.125qt). So although I added 14.25 qts I only get 6.125qt out so would need to add 21.875 qt to get to 28.

However, if I use an initial ratio of 1.5qt/lb the strike is 21.375 quarts at temp of 161F. After I lose the 8.125qt I pull 13.125qt on first runnings and only have to add 14.875qt in the batch - which although not 50:50 is close enough to get a good extraction.

Is that about right?
(Also, if there isn't enough headspace in the tun to add 14 qts, should I just split it into multiple batches as long as the 1/2/3 batches add up to 14 qts?)

Close, but 21.375 - 8.125 = 13.25, so you need to sparge with 14.75. You don't have to get 50:50 exactly. There is very little difference in lauter efficiency between 60:40 and 40:60. Also, you are better off mashing thinner, as thinner mashes have a higher saccharification rate than thick mashes, and this can improve your conversion efficiency (ref: http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency#Mash_thickness.)

Also, if the initial mash volume fits in the MLT, then the sparge water will fit if you are close to 50:50 for run off volumes. You would only have a potential problem if your sparge water volume was greater than your strike water volume.

Brew on

 

[wilserbrewer]

It really is so much easier that all that calculation. Use 1.25 to 1.5 quarts per pound of grain for the mash. Heat plenty of sparge water. Drain the tun after the mash is done. Measure how much you collected. Then sparge with enough to get to the amount you need to account for your boil off rate.

For example. If I collect 3 gallons from the mash, I know I need just over 7 gallons for the boil so I would need just over 4 gallons for the sparge.

I usually split the sparge in two additions. That way after the first sparge I have a pretty accurate number for what I need in the second sparge. This leaves very little water in the spent grains making it lighter to carry to the compost pile. And it might also help with efficiency by not leaving wort in the tun.

I like and use this approach as well. I would also suggest using this method as a check on your calculations as you progress through the process. What really matters is in your kettle, not what your spreadsheet predicted.

 

[murphyslaw]

Most brewing software/apps do this caluculation for you, too.

 

[GrumpyOldGit]

It really is so much easier that all that calculation. Use 1.25 to 1.5 quarts per pound of grain for the mash. Heat plenty of sparge water. Drain the tun after the mash is done. Measure how much you collected. Then sparge with enough to get to the amount you need to account for your boil off rate.

This looks like a good rule of thumb to ensure I get enough water to start with. What temperature do you sparge at - same as the mash, or aim for 170 to set the wort?

 

[kh54s10]

This looks like a good rule of thumb to ensure I get enough water to start with. What temperature do you sparge at - same as the mash, or aim for 170 to set the wort?

If you are batch sparging there is really no need to do a mash-out. That is more a process when fly sparging. Since conversion will continue while sparging for up to an hour while fly-sparging, a mash-out is used to stop that conversion. 170 degrees is what is suggested for a mash-out temperature. Not sure if that is for the water or the grain-bed after the water is added.

I go for about 168 degrees for the sparge water. That will not raise the temperature of the grain bed significantly. It is more, just to use hot water to possibly dissolve and rinse more sugars out of the grain than if you used cooler water.