How much water to use during batch sparging?

I am aware that 1.5 qts of water is the average per pound of grain when you do your mash but I tend to get confused on how much water I should be using for my batch sparging and how much wort I should collect per pre-boil for a 5-6 gallon batch. After that how much should I be boiling off.

I burn off a gallon every half hour, while other only boil off a gallon per hour. Depends on a lot of things. What is the surface area of the pot, how violent is the boil, burnwr size, etc. Every system is unique. Your best bet is to do a trail run with just water to find out how much you boil off in an hour...

I'd advise reading Ken Schwartz's page about batch sparging here. Ultimately, the idea is to work backwards from a desired pre-boil kettle volume to the amount of water required, taking into account grain absoprtion, dead space in your mash vessel, and your mash thickness. To work backwards from your desired post-boil volume to your pre-boil volume, you have to take into account evaporation losses, as well as wort absorption by kettle additions like whole hops, hibiscus petals, etc.

Like Hammy71 said, a lot of these factors are system- (and even recipe-) specific, so there will never be one right answer for all situations. Ken Schwartz also provides an excel spreadsheet that I've found to be useful in calculating my water volume.

I recently did my first all grain with batch sparging. I didn't feel like doing too many calculations, so I kept it real simple:
1.25-1.5 qt/lb for the mash. drain and measure volume of runnings. My estimated bioloff for an hour is 1 gallon, so after collectng 1.5gals of first runnings, I did two batches of 2.5gals each for sparging, leaving me with 6.5 gallons preboil, 5.5 post boil.
Once you have soaked the grains, they wont absorb water from the sparge water - they are already laden with their capacity of water. The trick is knowing how much you will boil off during your boil.

I kinda work backwards too. For a 5 gallon batch, I need a preboil volume of 7 gallons for a 60 minute boil. I mash with about 1.3 quarts/pound. I don't do any 'precalculations' for grain absorption. After the mash is complete, I draw my first runnings into a bucket that has gallon measurements on it. I then subtract my first runnings amount from my preboil total. Divide by two and you have the volumes for your two batch sparges. No need to worry about grain absorbtion during the sparge since the grain is already saturated.

Thanks for the replies guys, definatly a help. I'm still buying pieces to go all-grain and hope to do my first ag batch in a month or two. There is alot to take in that is for sure. Happy Beer Drinking!

I do something a bit different. I collect 7.5 gallons for a 5.5 gallon batch. That means I need to collect 3.75 gallons twice. The second water addition is 3.75 gallons. Everything you put in, you get out. The first addition (the initial mash in) is 3.75gallons + your dead space + your grain absorption. mash in with that much water. No need to worry about quarts per pound, just mash in with enough water to collect 3.75 gallons.

My methodology may seem complicated, but it is really very simple.

To make all grain work for me, I took copious notes for my first few batches about temperatures, time, and volumes. It took a few batches, but I learned my evaporation rate and grain absorption, which is crucial to hitting the right volume (therefore the right gravity).


Vb = (V1 + V2) - (Et)

Vb = volume at end of boil in gallons
V1 = volume of first runnings in gallons
V2 = volume of second runnings in gallons
E = evaporation rate in gallons per hour
t = boil time in hours

But how much do you need at the end of boil?

Again, work backwards.

I want 5 gallons of beer in my keg.

That means I need about 5.5 gallons in my fermenter.

Which means I need to have 6 gallons at the end of boil (after hop absorption and cooling losses).

Which means I need 8 gallons before I boil for 60 minutes. This is a relatively high boiloff rate, yours may vary.

I batch sparge with one round of batch sparging. This means: I mash, then mash out, then lauter first runnings. Then do one batch sparge.

I usually use 1.5 quarts/pound of grain because it is easy to calculate, but on higher gravity beers I will use 1.25 quarts/pound to keep V1 from getting too large relative to Vb.

For example, let's say I have ten pounds of grain. I will add in 15 quarts of strike water (3.75 gallons).

I mash out at 168. To make things easier, I use the "adjust mash temperature" calculator on beersmith. If my mash is 152F, I adjust the addition temp until I get a round number. To get to 168F, I need to add 1.5 gallons of 198F water.

That means I now have 5.25 gallons of water in my mashtun. The volume of first runnings (V1) can be predicted in the following equation:

V1 = (S + M) - (xG + D)

S= volume of strike water in gallons
M = volume of mash out water in gallons
x = grain absorption coefficient in pounds per gallon
G = pounds of grain
D = mashtun deadspace in gallons

I initially went to the trouble of measuring my mashtun deadspace, but then I realized it is unnecessary. Before I dough in, I add a gallon of boiling water to my mashtun to preheat it. I then run that hot water out of the mashtun while the strike water is heating up. Once that preheating water is run off, the mashtun deadspace is now full of water, eliminating the variable.

After several batches, I have learned that my grain absorption coefficient is 0.11 gallons/lb grain. That means I will lose 1.1 gallons in 10 gallons of grain. Referring back to the first runnings equation:

V1 = (3.75 + 1.5) - [(0.11)(10) + 0 ]
= (5.25gallons) -(1.1 gallons)
= 4.15 gallons

Now I know the volume of my first runnings without measuring. If I know that I need to boil 8 gallons, then my sparge volume (V2) is 8 gallons minus 4.15 gallons (V1) which is 3.85 gallons.

I then add 3.85 gallons of water at 168F and start lautering immediately. With my SS braid, it takes about 10 minutes to completely run off all 3.85 gallons.

Now I have 8 gallons of wort at the right gravity ready to boil. To ensure that my evaporation rate is correct, I take refractometer readings every 15 minutes and adjust my flame to compensate if needed. For example, if my preboil gravity is 10 brix and I need the OG to be 14 brix, every 15 minutes of a 60 minute boil, the wort gravity should increase by 1 brix.

Hope this makes sense. Please ask questions if it doesn't.

Eric

twoodward15 said:

No need to worry about quarts per pound, just mash in with enough water to collect 3.75 gallons.

Click to expand...

pardon me for saying, but isn't mash thickness pretty important?

NuclearRich said:

pardon me for saying, but isn't mash thickness pretty important?

Click to expand...

Yes, it does matter. It will affect your efficiency. When you are still learning your system and trying to replicate your process, I think it is a good idea to keep as many variables constant as you can. In fact, if you really want to nail down your process, make the same beer until you can replicate it - get the same efficiency, mash temp, volume, etc. Then start changing things up and see the effects.

Eric

I'm too lazy to do my own calculations.

I recommend some sort of brewing software to help with sparge volume.

I use BrewSmith and it hasn't steered me wrong yet when it comes to mash volume or sparge volume on my brew days.

bump 10 characters is a pain

NO, mash thickness isn't as important as you think. Try it your way and try it my way and I'll bet you won't notice a difference. Yes, I've done it both ways. No, there wasn't a difference on the few beers I tried it on. You can very mouthfeel and body with mash temps if you want to. It works for me, but it may not work for you. "if it works and you like it, do it that way, if not, then don't." I was taught that approach by a fellow brewer and it's workedfor me ever since he told me that saying.

Thanx for all the advice. I appreciate the different methods that everyone uses. I will have to find my happy medium and learn my system.