Author Topic: BIAB sort of  (Read 256 times)

Offline DarkBeer

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BIAB sort of
« on: December 27, 2019, 06:17:06 AM »
Hi,
I'm new to brewing and I hope that someone can help with advice to the following question.
I have a Klarstein 35 litre mash and boil kettle. It have a stainless steel grain basket insert which is the full size of the kettle.
I want to keg 23 litres (40 pints) and I will lose about 2 litres in the fermenter so I need a 25 litre batch post boil. During the boil I lose 6.5 litres. So this means I need 31.5 litres pre boil. But 31.5 litres of water plus the displacement of the grain is too much for the capacity of the kettle.
So my plan is to fill the kettle with 25 litres of water, add the grain into the grain basket and mash this for the appropriate amount of time. At the end of the mash I will lift the grain basket up on to the top of the kettle to drain and then, using water preheated to about 67 degrees centigrade, I will tip it on top of the draining grain ( sort of like a sparge) until I end up with 31.5 litres of wort in the kettle.
Do you think this will work satisfactorily, or am I missing something fundamental here?

Offline Oginme

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Re: BIAB sort of
« Reply #1 on: December 27, 2019, 07:37:01 AM »
That method would work fine.  I would recommend kind of doing a soft sprinkle of the sparge water through the grain basket to get the best possible rinsing of the sugars as a direct pour would create a quick pathway through the grain for the sparge water to bypass most of the grain bed.

When you look at modeling this in BeerSmith, your options become somewhat limited due to the way the software configures the volumes.   BeerSmith does a ratio of water to grain for the mash infusion volume and floats the sparge water to make up the difference needed for pre-boil volume.  This means that the program will give you different infusion volumes based upon your actual grist bill. 

There is a way to get around this though. When you build the equipment profile, you want to configure the volume you expect to sparge as "top off water to kettle."  In your mash profile, set the mash type to 'BIAB mash with full volume'. 

When applied to a recipe, you may need to make an adjustment to the 'top off water to kettle' amount to get the actual volume you are mashing with to be 25 liters.

Alternatively, you can set the 'top off water to kettle' in your equipment profile to be around 9 liters or so (the exact amount depends upon the grain absorption value for your system and you will need to calculate out where this makes sense to you) and allow the mash infusion to float based upon your grain bill. 

Either way, after a couple of brews worth of measurements and good notes and you should be able to figure out the best way to define your process in the software to accommodate how you want to brew.
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Offline DarkBeer

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Re: BIAB sort of
« Reply #2 on: December 27, 2019, 03:48:29 PM »
Thanks for the information Oginme, that's really helpful.

 

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