Top up water for kettle

Hi,

I have been having a few brews where my volume of wort collected is lower than expected but my mash efficiency is higher.
Basically like brewing a big beer.
I am diluting the wort in the kettle pre-boil to get to my expected pre-boil volume and gravity.

How do I input this in BeerSmith?
Do I add something to 'Top up water for kettle' in the equipment profile? When I do add something to this as a test, nothing seems to change?

Thanks

Or put another way, what is the purpose of the 'Top up water for kettle' figure and what does it change??

Thanks

Top up water for kettle is the right place.

Are you editing the equipment inside the recipe or in the main equipment profile?  The recipe has a copy of your main equipment profile, so you have to edit the recipe version not the main profile.

I'm not at my computer right now so I can't check to see if there might be a bug or something. 

Thanks Tom.

Yeah, I am editing the equipment profile in the recipe.
It doesn't seem to do anything?

Should it not adjust all the figures like efficiency etc, like the full diluted volume for total and good extraction in the mash so reflect mash efficiency?

Did you ever figure this out? I was wondering this too.

Top up water shouldn't affect anything like efficiency.  Efficiency is only about sugar extraction. So, if you are getting all the surgars out, but at a higher concentration (hence the low kettle volume) your efficiency will (and should) remain unchanged. 

I still haven't had a chance to play with Top Up water to see how it might impact basic volumes.  But, I really don't expect it to.  You have to remember that beersmith works backwards from batch volume.  It might affect sparge water volume, I'm not sure.  But, that's the only place I can see it having an impact. 

Preboil volume = batch size + trub loss + boil-off

Mash volume = grain weight * mash thickness + dead_space

Sparge volume = pre-boil volume - mash volume - dead space (- top-up water)

This is where I could see top-up coming into play.  -------------^^^^^^^^^  But, I'm not certain.

This is off the top of my head, I could be forgetting something.  But, it should be close.