# My formula - calculating sparge water

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#### ocbrew

##### Member
Here is my formula for adding water to the mash: X lbs * 1.1 quarts = y, y/4 = gallons of water for the mash. This is what I have been taught by a number of micro brew stores. My problem is the sparge--how much do I draw? Considering the fact that I am making a 5 gallon batch and I know that some of the wort will boil off - how much do I draw off the sparge? I hope that helps you -- can anyone help me? I have been making light/thin beer and I wonder if my sparge is too long and I am just thining out my wort too much.

Thank you

#### Arneba28

##### Well-Known Member
With a 5 gallon batch if your doing a full 60 boil and boiling all 5 gallons you should be loosing somewhere around 15-19% loss per hour. So if you are loosing 17%/hr you need just under 6 gallons of total wort to boil down to 5 gallons

final volume x 1.(%boil loss) = total volume collected pre boil

That ^^^ will give you the amount that you need in your boil kettle in order to end at 5 gallons

Say I want 5gal final volume and I lose 17% per hour. Doing a 60min boil
5 x 1.17 =5.85gallons that will be needed to be collected before I start the boil.

If at the end of your boil you still didnt hit 5 gallons for some reason, boil a little longer. This will not effect much. You color may darken a bit but thats it.

Also If your beer is to thin/light/watery you may want to look at your recipes. If your recipes are formulated for 5 gallons and you are overshooting your sparge or under your boil you might be ending at 5.5/6 gallons, this will greatly effect your taste/og/fg readings.

#### bgrubb7

##### Well-Known Member
I don't worry about trying to precalculate my exact sparge water volumes. I know that I boil off around 3/4 gal during an hour boil. I also figure in 1/4 gal loss to trub/hop absorption (whole hops). If the recipe with a huge amount of whole hops, I'll add an additional 1/4 gal to that. I normally shoot for a preboil volume of 6 gal.

I always mash with 1.25qt per lb of grain. I figure I'll lose approx .1 gal per lb due to grain absorption, but I don't usually even bother calculating that.

I have a yardstick with gallon marks that I can stick in my boil pot to measure volume. After I drain my mash runnings into my boil pot, I measure my volume. If I've got 2 gal in there, then I need 4 gal of sparge water. I'll usually add an extra gal to what I'm heating up, so I have it ready i case I need it.

If your beers are too weak, then it sounds to me like you're just not calculating your recipes properly. I'd recommend using some software, like Beersmith, ProMash or BeerAlchemy (mac). You can plug in your desired preboil and post boil volumes, and then adjust your grain bill till you hit your target gravity. I use BeerAlchemy and am usually within a couple points every time. There is also a decent recipe calculator at tastybrew.com that is free to use.

#### Got Trub?

##### Well-Known Member
ocbrew;

You need to take some measurements the next few times you brew. Everyones system and process differs so you can't just use others numbers. It also depends on if you batch or fly sparge.

The things you need to measure are the volume lost to your mash/lauter system. You will then be able to calculate exactly how much water to use to sparge with.
You must then calculate how much loss to evaporation you have with your boil. This is a little trickier as none of us have exact control over our propane burners. I have two values, one for a gently, barely ticking over boil and one for a vigorous boil.

Once you have those dialed in - and it can take a couple of brewing sessions - you can more accurately calculate your brewhouse efficiency and formulate recipes that will get you the preboil and postboil gravity you desire.

It is a bit of work, but well worth it in the long run. I can hit within 1 point my gravity postboil consistently.

GT

#### bgrubb7

##### Well-Known Member
Got Trub? said:
ocbrew;
This is a little trickier as none of us have exact control over our propane burners. I have two values, one for a gently, barely ticking over boil and one for a vigorous boil.
GT
Very True. On my last brew, I ended up a little high in my preboil volume, and a couple points lower than my target preboil gravity. I decided to crank up the burner and try to boil off a little extra during the same hour boil time. I ended up boiling off 1.25 gal instead of the normal .75 gal during the same amount of time. Ultimately I ended up with a little less wort, but a couple points higher than my intended post boil gravity.

So you also want to keep your boil rates consistent between brews in order to get an accurate boil off rate.

#### Got Trub?

##### Well-Known Member
bgrubb7 said:
Very True. On my last brew, I ended up a little high in my preboil volume, and a couple points lower than my target preboil gravity. I decided to crank up the burner and try to boil off a little extra during the same hour boil time. I ended up boiling off 1.25 gal instead of the normal .75 gal during the same amount of time. Ultimately I ended up with a little less wort, but a couple points higher than my intended post boil gravity.

So you also want to keep your boil rates consistent between brews in order to get an accurate boil off rate.
Yes you do and if you are doing a 90min boil it is even harder to hit your final volume and gravity, especially if the G*& D&^* wind kicks up part way through the boil and you have to crank up the flame so the burner doesn't get snuffed. Not that that has ever happened to me....

GT

#### Bobby_M

##### Vendor and Brewer
From my page: http://www.suebob.com/brew/allgrain.htm

Just Step 5 in my method...

After the full 60 minute mash, open the drain valve on the MLT and collect 2 quarts of wort into a pitcher. Carefully return this back on top of the mash (this is vorlaufing), then drain the entire MLT into a bucket. If the bucket has graduation marks, take note how much wort you collected. You're going to find that you lost a good percentage of liquid to grain absorption. In our example, it's likely that you only got out 2.5 gallons from the 3.75 strike volume. Here's where you have to decide ultimately how much wort you want in the kettle to start with. You will boil off about 1.25 gallons in 60 minutes of vigorous boil so you'll want at least 6.5gallons to start with. To figure out how much to sparge with, take this pre boil figure (6.5) and subtract it from how much wort you collected out of the MLT for first runnings (say 2.5). This leaves you with 4 gallons. This is exactly how much you'll need to sparge with.

OP
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#### ocbrew

##### Member
Thank you all--this has been most helpful. I think I need to kick up my recipe and start tracking my volumes and measurements much better. I have had few of those flameouts in the boil lately too -- so that has likely not been helping my consistency either. Thanks again!!