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BIAB water volume calculation


Nov 17, 2016
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I'd like to use Beersmith software to calculate water quantity for BIAB tecnique production
I've downloaded the last release and I'm using in trial mode.
I've got a 20 liters keetle. I've made the receipe putting the right ingredients .
Which is the right procedure to calculate water and ingredients weight to fit my keetle ?

Set up your equipment profile using the volumes of your kettle and known boil off rate/brewhouse efficiency as a start.  If you don't know these right now, you can correct them after your first few brews.  Next look through the mash profiles and pick out a BIAB mash profile to use.  Edit it to make sure it fits your desired mash temperature and that it is set for BIAB.  Save this profile under a new name so you can find it easily.  When you change or create a recipe using your custom equipment profile, use this mash profile and then on the 'mash' tab make sure that the 'adjust temp for equip' is unchecked. 

BeerSmith will then calculate out the water needed for a full volume BIAB.  It will probably need some adjustment after you brew to dial it in to your particular process, boil off rate, grain absorption, and process losses.  Continuing to adjust it will better tune it in to how you brew and make it pretty accurate.
I've created the equipment profile ; I know my keetle max volume in liters and I supposed to have a 65% efficiency.
1,6 liters boil off  in 1 hour.
Now I suppose to not know the batch volume. I know only the fermenter loss.
what value do I add?
Batch volume is the volume of wort you transfer into your carboy.  BeerSmith will use this target and the volume losses through the rest of your process to figure out the beginning water volume.

It will also use this volume into the fermentor and your total efficiency (brewhouse efficiency) to calculate the gravity readings for the amount of grain you add into the recipe.
well, I've done my test receipe to understand the software logic.
Biab receipe
Mash tune volume 19,9 liters
Mash biab profile selected
Mash Grain weight : 4,3 kg

The software tells me to add 15,69 liters in the Keetle to begin the mash process; mash volume calculated is 18,49 liters . I don't understand why;I would have said that it was 19,99 liters.
The mash volume is the actual volume of the water plus the volume of the grains when added.  This is used as a check to make sure that you don't exceed your mash tun max volume (19,99 liters). 
Does it means 1 kilo grain volume  is like 650 ml of water ?
Yes, the displacement of water by the grains is about 650 ml.  Some of the water will be absorbed by the grains as well, but the net result is that each kg of grain will raise the volume of the water by 650 ml.

ok, well

If I'll buy a 36 liters keetle could I produce a 21-22 liters batch in high density too ?

I think that 36 liters is cutting it a bit close for a 20 liter batch.  You need to figure on boil off volume, grain displacement and any process (trub) losses you may have in your process.

For example, I brew 10 liter BIAB batches in a 20 liter kettle.  It fits, given that I plan on 11 liters post boil (10 liters in fermentor, 1 liter trub), my boil off rate is 2.2 liters/hr, so for a 90 minute boil, I am losing 3.3 liters.  That gives me 14.3 liters pre-boil volume at room temperature.  My grain absorption is .5 liters/kg of grain and a high gravity brew for me takes around 3.5 kilos of grain.  So that adds another 1.8 liters of water needed for mashing in.  Since we have established that the water displacement of the grain is 0.65 liters/kg of grain, this adds 2.3 liters of volume needed in the kettle.  So my volume of 14.3l plus 1.8l for grain absorption and 2.3l for grain displacement gives me a total required volume for my kettle of 18.4 liters.  Just fits, but leaves not so much room for mixing and stirring in the grains.

Luckily, I get pretty good mash/lauter efficiency from my system.  If I had a lower mash efficiency, say 70%, I would be overflowing my kettle with the increased grain bill.

Take similar figures from your brewing and size up what you might need for volume for a 21 to 22 liter batch and then add a bit of a safety factor of a couple of liters just to be on the good side of things.

thanks for the excellent explanation. I've calculated a 36-37 liters keetle volume for a 20 liters batch at high gravity or 23 liters at normal gravity (1050)

I've found in an online store a  38 liters keetle ( ssbrewtech) at good price.

Another question is to find the right heater element to use electricity to warm up water.
The 38 liters keetle has 35 cm diameter an a lot 2,5 kw heater are the same lenght so no space to fit right in it.
Electric elements are a bit beyond my experience.  You might have luck re-asking the question as a new thread or searching existing threads as I am sure this question has been asked and covered before.