Water requirements

[ModlrMike]

I'm starting out in the BIAB world after being an extract with grains brewer for a long time. I've got a recipe developed (posted below), but I'm having some challenges figuring out my water needs. My equipment is minimal at this point, I have a sous vide wand for mashing, and an 18L (5 gal) pot for boiling. I can easily go out and get more equipment, so don't be shy making a suggestion. Anyhow, given that I want to do a 5 gallon batch, what would I use for water? My own math tells me that I should have something on the order of 9 gallons of strike water to start, but that seems very generous even with a mash thickness of 4.5. I've also read that longer mash times for BIAB pretty much negates the need for sparging.

Lawnmower Cream (Partial Mash BIAB)

2.2 lbs American Pilsner
2.2 lbs Canadian 2 Row
4 oz Honey Malt
8 oz Munich Light
3 lbs Extra Light DME (late addition)
.25 oz Citra (60 min)
.25 oz Citra (15 min)
.25 oz Citra (5 min)

Mash at 152 for 90 minutes. 60 minute boil. OG: 1.50 FG: 1.009 ABV: 5.4 IBU: 17 SRM: 4

 

[frozyn]

Get a bigger kettle. I'm assuming you're mashing in the kettle as well, and the rule of thumb is to have a kettle that is (at least) 2X the volume of your batch size. So, 10-12 gallons, perhaps 15 if you someday want to do high gravity beers without any sparging.

Also, I agree your calculated strike volume seems high. Using my own 5 gallon kettle/boil off information in the Priceless calculator, and only include 5.15 lbs of malt (since the DME doesn't need mashing), it says I would need 5.92 gallons of strike water, which would be 4.6 qt/lb. Given that high mash thickness, I don't think you would need a 90 minute mash. Conversion should happen quite quickly at ~4.5 qt/lb.

If you get a bigger kettle, you can do a full mash. Otherwise, you would need to top off after the boil, given your current kettle size. I haven't done that since following recipes for my first two extract attempts, so I cannot guide you there.

 

[mredge73]

You certainly cannot do this with a 5 gallon pot, you need to upgrade this for sure. 7.5-10 gallon works well.

Your grain weight is 5.15lbs, using a water absorption rate of 0.14 gallons per lb the grains will absorb 0.7 gallons and not give it back.
Some water will evaporate during the mash, this will be dependent on your equipment and if you use a lid or not. Lets just say 0.1 gallons for now.
Boil evaporation is also dependent on your equipment, mine is 1.25 gallons per hour so lets use that for now.
Hops will absorb some water, you will need to count the hop cone as a loss. I use 0.15 gallons per oz but there is no science behind this. Lets call that 0.19 gallons.

So by these calculations you need 7.24 gallons for a 5 gallon batch.
If you use 9 gallons you will have to boil for 2 hours to get the volume down to 5.5 gallons.
Take these numbers and build yourself a spreadsheet. Add volume markers on your kettle and record water loss at each stage to refine these numbers.
You should be able to hit it perfect after a couple of brews.

 

[pricelessbrewing]

I've also read that longer mash times for BIAB pretty much negates the need for sparging.

Lawnmower Cream (Partial Mash BIAB)

2.2 lbs American Pilsner
2.2 lbs Canadian 2 Row
4 oz Honey Malt
8 oz Munich Light
3 lbs Extra Light DME (late addition)
.25 oz Citra (60 min)
.25 oz Citra (15 min)
.25 oz Citra (5 min)

Mash at 152 for 90 minutes. 60 minute boil. OG: 1.50 FG: 1.009 ABV: 5.4 IBU: 17 SRM: 4

RE: 90 minute mash does NOT do the same thing as sparging. Sparging increases lauter efficiency, meaning your use of water and wort volumes is higher. Mashing longer increases conversion efficiency, meaning more of the starches in the grain was converted into sugar. If your conversion is high already (good crush, good pH, good dough in process), then mashing longer is not going to do anything substantial. Mashing longer can help sometimes if you're not controlling mash pH (typical for new brewers), and you don't have a good crush (typical for getting your crush done at the lhbs).

9 gallons is definitely too much. You're looking more around 6 gallons.

5 gallons + ~0.75-1 gallon boil off rate + 5.15 total lb of grain * 0.08 gal/lb

If you're mashing in your 5 gallon kettle, then you'll need to either top off twice (once at the start of the boil, or sparge up to 4.5 gallons preboil volume), or top off a lot after chilling.

My suggestion:

Strike : 4 gallons @ 157.1F (gets to mash temp 152 with 5.15 lb of grain).

Mash:Turn off burner. Add bag, add grain, stir like mad for 5 minutes. Cover kettle, throw some towels/sleeping bag/blankets on it for an hour.

First runnings: Pull the bag, squeeze. You can now either sparge with ~0.75-1 gallon, or top off the preboil volume with it. If you sparge, you'll get a higher OG (more sugar, abv, body etc).

Boil and proceed with hop additions and DME addition.

Post boil: Chill and rack/pour into fermenter. You'll likely have ~4 gallons, so you'll need to top off again with another gallon or so.

 

[pricelessbrewing]

Y
Your grain weight is 5.15lbs, using a water absorption rate of 0.14 gallons per lb the grains will absorb 0.7 gallons and not give it back.

0.14 gal/lb is extremely high, and is not applicable to BIAB.

 

[frozyn]

Ran across this post from Revvy about diluting AG that answers the questions I couldn't earlier. This is something you could use to pull off 5 gallon batches with your current 5 gallon kettle.

 

[ModlrMike]

Just back from my storage shed and I actually found that I have a 30qt (7.5gal) turkey fryer pot. This should give me some extra room to work with.

 

[mredge73]

0.14 gal/lb is extremely high, and is not applicable to BIAB.

I don't understand, the grain is the same if you are sparging or not.
This number has worked for me for years.

Unless you guys are squeezing the bag? Is this a thing people are doing now, conventional wisdom has always been to not squeeze the bag.

 

[pricelessbrewing]

I don't understand, the grain is the same if you are sparging or not.
This number has worked for me for years.

Unless you guys are squeezing the bag? Is this a thing people are doing now, conventional wisdom has always been to not squeeze the bag.

Traditional grain absorption is typically 0.12-0.125 gal/lb. 0.14 is pretty high even for that. You likely have a flat mashtun deadspace loss that's not being accounted for

BIAB (where you squeeze the bag, or hoist it to allow the bag to drain via gravity) is typically ~0.08 gal/lb.

Re: Squeezing

This has been disproven again and again. Tannings are a function of pH, and to a much lesser extent temp (decoctions don't get much tannin extraction after all despite boiling).

This misconception came up because back in the day, the only time grains were bagged was for steeping grains in an extract batch. Due to the much thinner "mash", and the lack of water chemistry, this is steeping in a much higher pH and will cause tannin extraction, so you generally don't want to squeeze when "steeping".

 

[RM-MN]

Just back from my storage shed and I actually found that I have a 30qt (7.5gal) turkey fryer pot. This should give me some extra room to work with.

A 30 qt pot is minimal for size on a 5 gallon batch and a sparge step may be necessary to avoid spilling. You also have to watch the pot as you bring the wort to a boil to avoid boil overs. I've used one and made a few batches so I know it can work. Start with a smaller volume of water so there is room for the grain, sparge to desired volume. If you boil off too much water, add some back to maintain your 5.25 gallons that you want into the fermenter.