First BIAB brew - calculating Boil Volume

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BrewJas

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Hi

I'm planning on doing my first BIAB brew this weekend and wanted to check how I work out the volume of water needed for the mash

I have a 19L pot and I am looking to adapt the following receipt posted by Clibit a while back

Batch Size (L): 10.0
Original Gravity (OG): 1.046
Final Gravity (FG): 1.012
Alcohol by Volume (ABV): 4.52 %
Colour (SRM): 3.4 (EBC): 6.7
Bitterness (IBU): 33.9 (Average)

2.000 kg Pale Malt (100%)

15.0 g Cascade Leaf (6% Alpha) @ 60 Minutes
10.0 g Amarillo Leaf (8% Alpha) @ 10 Minutes
10.0 g Cascade Leaf (6% Alpha) @ 10 Minutes
10.0 g Amarillo Leaf (8% Alpha) @ 0 Minutes
10.0 g Cascade Leaf (6% Alpha) @ 0 Minutes
Plus a dry hop of maybe 10-15g each for extra aroma

Mash at 66-67ðC for 60 Minutes.

I want to be able to bottle 10L, so I'm trying to reverse calc the water I need. So if I want to bottle 10L, I need (working back)

+1L loss in the fermentor for trub (my estimate)
+2L loss for boil evaporation (my estimate)
+1L loss for grain absorption (John Palmer suggests 0.5L / kg)
=14L mash

Does this seem right? If I mash 14L, do I need to increase the Malt by 40% (i.e. 2.4kg) in order to hit the same target gravity?

Any help appreciated!

Thanks
Jason
 
I'm interested in answers to this too as working out water does my head in, to the point where I wing it. I'd suggest that grain would only go up by 20% though, based on your figures, as you'd lose no sugars etc from the boiling stage.
 
Water loss from grain absorption suggested in BrewersFriend windows app is 0.9L/kg. This usually works out right for me. It depends how hard you squeeze the bag, and I squeeze pretty hard.💪

On a 23L batch my losses from boil are around 2.4L for a 60min boil (works out around 10%). Boil losses can depend on vigour of boil and cross sectional area of your kettle - you'll lose more from a short wide vessel than from a tall narrow one.

1L is a good estimate for trub loss.

Trying to solve this for you...
I've run this through the BrewersFriend app for you. I plugged in Safale US-05 as the yeast. Considering you've accounted for 1L of trub in the FV, I used a batch size of 11L. This also means upping your hops to get the same IBU

You'd have to hit 80% brewhouse efficiency to get that OG of 1.046 with 2kg of grain. Typically a good number to start at for your first BIAB is 65% efficiency, which would either:
  1. Give you 1.037 OG and a possible 3.9% ABV
  2. Or, require 2.400kg of pale malt to give you 1.045 OG and 4.8% ABV
This all gets a bit tricky to predict. The yeast you use and the success of your fermentation will influence your FG. US-05 is listed as 81% attenuation, so it may get you lower than your listed 1.012 FG. Other yeast will give you different mileage, S-04 may be closer to 1.012 but wouldn't suit the style (american hops) as well as US-05.

Here's what you get with US-05 and 2.4kg of pale malt:

1591285854295.png

1591285877099.png


Total water 14.89L for that weight of grain.

I hope that helps
 
Hi cushyno, thanks so much for taking the time to plug the numbers in, that’s really helped and gives me more confidence for my first brew! And as it happens I am using US-05!

I need to get the brewers friend app, looks invaluable and straight forward to use.
 
The way to work out losses through boil off (well how I did it any way):

-Put 5L of water in your pot
-boil it for 30 mins
-measure how much is left
-minus this from 5L
-Double it gives you boil off for your 60 min boil
 

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