BIAB water help please

[Smokey.]

Hi. Doing my first BIAB this weekend using a Peco boiler and trying to get water volumes. Have visited biabcalculator.com and entered info required, 4.5kg grain, 23l brew, 66oC mash for 60 mins, kettle size 32l, left trub a 0.9, left boil off rate at 4.7 and changed grain absorption to 1kg per liter.

It says my kettle is too small as the total mash vol will be 36l approx needing 33l of water. So is it at easy as splitting the total required amount of water in 2 and using say 20l to mash and then remaining 13l to sparge after?

Thanks

 

[Galena]

Hi
I have put this into Brewfather (worth getting as its free for up to 10 recipes btw) and got a rough ball park figure for you.
So yes, what I do is to split the water into mash and sparge, when the mash is complete drop all the wort into a bucket.
Then pour on the sparge water, stir well and leave for 5 mins. Drop that into the bucket (or a second bucket if weight/volume is an issue) then drain the grains and remove.
Pour all the wort back in the kettle, accoding to my calcs that should be 30.56L (on my equipment) so you will need to be careful with the hot break. I never had a boil over by stirring like mad as it starts to rise and if that fails spray some cold water from a spray bottle on it.

Alternatively you could brew short and top up towards the end of the boil to reach your target OG

 

[Smokey.]

Okay, makes sense. So am I right in the assumption then that if it says 33l of total water required I can split that into 2 amounts of say 20l and 13l? 20l for mash and then the remaing 13l for sparge? Or is it mash in 20l then sparge until I hit the preboil water target?

 

[Galena]

Well, assuming it is actually 36L total water as you originally stated (and I calculated) and not 33L as you just said and assuming a grain/water ratio of 3l/Kg which is about right for BIAB in my experience then you would get the following according to Brewfatther for my equipment

Mash water 18L
Sparge Water 18.09L
Total Water 36.09L
Mash Volume (Water + grain) 21.02

So add 18L to your kettle and bring to your strike temperature, this for me is 70.6C, then dough in and stir which should reduce to 66C
Mash for 60 mins at 66C
Drain all water into a bucket
Add 18.09L Pre heated Sparge water (75 or 76C) to the kettle with the grain, stir well and leave for 5 mins then drain that into bucket
Remove grain bag when drained (you can squeeze a little if you wish.
Pour all wort from bucket(s) back into kettle, this should be pre boil volume of 30.56L (You have lost some in the grain absorption.
Proceed with boil

 

[Caramel Ox]

I would have estimated your boil off rate at about 2.4 and grain absorption at 0.7 if you squeeze the bag. Putting those numbers in should show that you are within limits. I also recommend Brewfather, setting an equipment profile and tweaking it from experience.

 

[foxy]

Hi. Doing my first BIAB this weekend using a Peco boiler and trying to get water volumes. Have visited biabcalculator.com and entered info required, 4.5kg grain, 23l brew, 66oC mash for 60 mins, kettle size 32l, left trub a 0.9, left boil off rate at 4.7 and changed grain absorption to 1kg per liter.

It says my kettle is too small as the total mash vol will be 36l approx needing 33l of water. So is it at easy as splitting the total required amount of water in 2 and using say 20l to mash and then remaining 13l to sparge after?

Thanks

You don't need to put all the water in for the mash, just put as much as possible, if you add salts add them to the full volume of water remove four or 5 litres of water and add the grain. If there is any space left add some water back, you are making a more concentrated wort which will be a higher pre-boil gravity so adding the water back straight into the kettle should bring it back to the estimated pre-boil gravity..
To squeeze the grain bag make a set up where you can reclaim as much wort as possible from the grain, a large commercial colander, and a large plastic bowl and squeeze it like you mean it getting as much wort out as possible.
Your boil-off could be as much as you have predicted based on the surface area of the boiler. The loss to trub in the kettle @ 0.9 seems on the low side, the dead space is what predicts your loss to trub without tilting. So if you have 2 -2,5 litres under the tap that is your loss to trub without allowing any into your fermenter, only clear wort into the fermenter will give you accurate efficiency.
Whatever is left in the kettle pour into a jug and set in the fridge, the trub will settle out and you can add the remaining wort into the fermenter after sterilising.

If you aren't crushing your grain make sure that it is crushed for BIAB or your conversion won't be as expected. Make exact notes on all your losses and gravity if you want to continue doing 23-litre batches, you may need to add a touch more base malt.

 

[jof]

Start with working to the perceived wisdom and get a feel of how it all works.
Later you can change your process a little to see what works for you.

For my BIAB with 4.5kg (and below) malt, I split water into 3, with 1 mash & 2 sparges. The mash will be thicker and it will take a little longer, but it works for me.
But if I make a stronger beer with more malt, I would need to revert to a single sparge as the mash would end up too thick ( like porridge)