Fine tuning my mash and equipment profile for my BIAB with 'sparge'

[Leard]

Current I'm BIABing using the medium body BIAB profile on Beersmith. After the mash I squeeze my bag out into a seperate bucket and then pour that into the kettle before taking a gravity reading.

However I'm left with 4-5L of deadspace in the kettle and so I would like to include a 'sparge' step to increase my batch size. I'm going to take the bag out, let it drain into another bucket, and then pour 4L of water of the bag before I squeeze it. I'll then pour that liquid into the kettle.

How can I set this up in Beersmith so it's taken into account? I considered using the 'Kettle top up' field, however presumerably this just refers to water and so it wouldn't account for the specific gravity of the sparge addition.

[Oginme]

You have identified the spot to add your 'sparge' step if you are considering a constant 4 liter sparge.  The program does not know (or care) that the water you add has been poured through the grains or not.  You will end up with two gravity targets that you need/want to pay attention to.  The post mash gravity will assume that the water you add does not contain sugars though it will have teh total sugars you recover once you update your brew house efficiency based upon the sugars you extract due to the sparge. This figure is really not an issue for what you are doing and you can enter in the value for the initial mash run off gravity as a measure of how your actual mash extraction is performing per-sparge.  The pre-boil gravity will account for the addition of your sparge water in terms of volume and will reflect your desired target gravity of your mash + sparge volumes.

You are trying to overcome the 4 to 5 liters of wort left in your kettle. If this is after your boil, then this volume should be listed in your equipment profile as 'loss to trub and chiller' and the program will adjust the volumes accordingly to account for that loss.  This would then account for your batch size as the amount which you will end up with in the fermenter.

The pour through sparge step is still an option to try to improve your efficiency and you can still set it up as above to account for this step.