Originally Posted by BillyBroas
After more hunting around and talking with people it looks like there's no way to directly enter your mash efficiency. You have to use one of the methods I listed or zero out your equipment losses so that brewhouse efficiency equals mash efficiency, although that may not accurately represent your system.
It's pretty inconvenient and hopefully it gets fixed in an update.
This past summer I raised a big stink about the use of 'to the fermenter' eff over in BeerSmith fanboy world, and elsewhere. It seems to have increased the visibility of the issue, as well as the knowledge level of the user about its downsides. Prior to this, the fanboys touted it as a benefit. There have been some posts lately from BeerSmith hinting that he may be adding the ability to go off 'in the kettle' efficiency in the future. At least now BeerSmith and the fanboys can't spew their usual propaganda at new users, since a search so easily turns up results about why it is stupid.
The trick of setting 'trub loss' to '0' is the preferred workaround. A single 'loss' field for equipment isn't really representative or useful anyway. Trub loss will change based on the recipe- pellet vs cone hops, wheat vs. barley, high/low gravity, etc. My advice is to keep track of trub loss for a recipe using the 'fermenter loss' field. When building/tuning a recipe, you just need to scale it to 'kettle volume', which is trub loss + ferm volume. This method allows changing trub loss volumes (i.e. pellet vs. cone hops), while not affecting efficiency (which wasn't changed). If the trub loss field is used, the efficiency would have to be adjusted anytime the trub loss field is changed, since BS uses that value in its calcs.
The kettle loss issue is a tricky one, since the amount of trub is usually, but not always, more than the dead space anyway. If you suck any of that junk into your fermenter, you will just be losing volume down the line. It is much better to allow for it, and that way the fermenter fills, or you cut it off, before the trub pile starts getting sucked in.