Boil Volume vs. Batch Size

Getting ready to brew a big beer (DIPA) this weekend. All grain doing mash/sparge technique(first time). Doing some calculations on TastyBrew.com. I know what batch size is (5 gallons). What is the Boil Volume? Is that the total amount of water I will be using for this batch? Or is this the amount used for the mash. My mash water will be around 4 gallons (14.5lbs grain) & my sparge is around 6 gallons of water. For a total of 10 gallons. Thank you.

Boil volume is the amount of wort in your boil kettle before you start boiling. For example, I need to start with a boil volume of 7 gallons to hit my batch size of 6 gallons, because 1 gallon will boil away.

You need to take into account grain absorption, mash tun losses, etc. You aren't going to get 4 gallons out of your mash (more like 2 gallon tops). 6 gallons sparge is a bit high as well.

This is a good thing...you don't want 10 gallons pre-boil...that will take many hours to boil down to 5 gallons.

Also: you are doing a DIPA with 14.5 lbs of grain? Seems low to me, unless you are going to add some simple sugars.

I have a 10 gallon pot and collect about 7 gallons total aiming for just over 5 gallons into the fermenter. This is boiling for 69 minutes.

How much boils off is dependent on the pot depth and diameter, ambient temperature and humidity.

10 gallons seems way too much to end up with a 5 gallon batch.

If you are fly sparging you might start by heating more water than you need and collect the sparge liquid until you hit your pre-boil volume. Again I would say that you want about 7 gallons not 10

If you have a separate HLT to store sparge water, do as kh54s10 mentioned and keep collecting runnings from the MLT until you hit the preboil volume, usually measured by sight-glass or marked mash-paddle/spoon.

I find this to be much easier than trying to get all of the volumes right from the beginning and later finding out your absorption or measurements were off.

So, to sum, heat extra sparge water, more than you need, and just stop sparging when you hit preboil.

kh54s10 said:

I have a 10 gallon pot and collect about 7 gallons total aiming for just over 5 gallons into the fermenter. This is boiling for 69 minutes.

How much boils off is dependent on the pot depth and diameter, ambient temperature and humidity.

10 gallons seems way too much to end up with a 5 gallon batch.

If you are fly sparging you might start by heating more water than you need and collect the sparge liquid until you hit your pre-boil volume. Again I would say that you want about 7 gallons not 10

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Okay. My recipe calls for 13lbs 2 row, 6 oz crystal 40L, 1lb carapils, 1lb corn sugar(says to be added to last 10min of boil), and a whole lotta hops (2oz for the mash, 7oz total for the boil & 5 oz for dry hopping).

Using the calculation for mash water (___lbs x 1.1qts = ___/4 = ___gallons), my total mash water should be 3.8 gallons(4gal). It says for sparge water use 1/2 gallon for every lb of grain. That comes out to over 7 gallons! Now when I'm sparging I don't necessarily use all 7 gallons? I sparge until my boil pot fills to the boil volume, correct? Is that the correct way of doing it? Or should my sparge water be less than 7 gallons to start off with?

I should also mention that I am using a 10 gallon cooler for the mash and a 5 gallon cooler for the sparge water. Setting it up as a three tier system.

You'll absorb water in the grain. If you're not using a software to help with this, you have to at least know your boiloff rate (wider pots boil more, closer to 1g/hr). You can calculate your strike water for mashing as you did above, then heat up more sparge than you might need and stop sparging when you hit preboil.

I generally need almost 9g. of water total for a 5.25g. batch. My sparge is usually nearly 6g. My preboil is about 6.75g. total. You'll have hop absorption and trub-loss, so you want to end up about 5.25-5.5.

Because of the size of your grain-bill and hops, yes, I would plan on heating 7g. of sparge water and plan on using most, if not all of it.

tre9er said:

You'll absorb water in the grain. If you're not using a software to help with this, you have to at least know your boiloff rate (wider pots boil more, closer to 1g/hr). You can calculate your strike water for mashing as you did above, then heat up more sparge than you might need and stop sparging when you hit preboil.

I generally need almost 9g. of water total for a 5.25g. batch. My sparge is usually nearly 6g. My preboil is about 6.75g. total. You'll have hop absorption and trub-loss, so you want to end up about 5.25-5.5.

Because of the size of your grain-bill and hops, yes, I would plan on heating 7g. of sparge water and plan on using most, if not all of it.

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My boil pot is the usual turkey pot fryer. 7-8 gallon aluminum pot. I do have 15 gallon aluminum pot I bought at the swap meet. But don't think I need that big of a pot. I used that pot on my last batch which I did a BIAB.

So is my calculations correct then as far as the mash water & sparge water? How much boil volume do I need then? 6.5 gallons?

When I had a turkey fryer I boiled slightly less than 1g/hr but I wasn't on propane, I was stove-top so my boil might have been less vigorous.

I'd shoot for 6.5. You'll absorb plenty in the hops and then boil off nearly another gallon. You'll need to be careful though because most of those turkey fryers are 30qt, or 7.5g. I'd gently boil for a while until you can afford to turn it up and not have a boilover. After the initial foam subsides.

tre9er said:

When I had a turkey fryer I boiled slightly less than 1g/hr but I wasn't on propane, I was stove-top so my boil might have been less vigorous.

I'd shoot for 6.5. You'll absorb plenty in the hops and then boil off nearly another gallon. You'll need to be careful though because most of those turkey fryers are 30qt, or 7.5g. I'd gently boil for a while until you can afford to turn it up and not have a boilover. After the initial foam subsides.

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Great! Yes, I will be boiling with turkey fryer burner. My last batch was another big beer and I had 17lbs of grain to boil. I did the boil in a bag. I threw in 9 gallons of water into the 15 gallon pot. I ended up with exactly 5 gallons in my ferm bucket. So this time I'm stepping it up by using the mash/sparge technique. I'm getting ready to bottle that one. This one I will keg it. Thanks again!