I will start with 'I dont do this, and I dont recommend it'. Mostly cause its difficult for me to figure if its correct or not. And there are programs that are more user friendly. Most things in Beersmith I used to think were messed up I have now found Beersmith wasnt messed up, I was. This isnt one of them.
Go to Ingredients, Water. Pick any profile, copy, paste, rename, change values to show whats in your water report. Go to Tools, Water Profile Tool, click Base Profile and select your newly named water profile from the drop down list. Your water values will appear in the boxes. Slide down to Target Profile and select the target water you want to emulate so its values appear in the boxes. Now slide to the bottom and click on Calculate Best Additions. The additions Beersmith calculates appear in all the individual boxes for minerals. Slide over and click Save Additions to Target. A box will pop up and you can tweak the numbers if you feel its needed. Click OK. Close the tool.
Go to your Recipe, Design Page. To the right of the big white box listing all your ingredients click Add Water. Click the water profile you want to emulate. In the pop up box, go to the bottom where it says Amount and change that value if you want to the volume of water you wish to treat. It will ask you if you want to add the minerals. Say Yes. It will populate your recipe with the calculated mineral additions and will appear in your Brew Steps printout.
The Water Profile Tool has limitations as discussed in this thread and many others and I wont start listing them in this response, I have to get to work. Most users use other programs. I use Bruin Water alot and also Kai's calculator at Brewers Friend. You can use an outside program for your calculations, then manually add them to the recipe list of ingredients by clicking Add Misc, highlight mineral, change amount at the bottom, add to recipe. You can seperate them into mash additions and kettle additions by double clicking the mineral once they are in your recipe and change Use In to Mash or Boil.
I dont do any of the above, just print out my water calculator from Bruin or Brewer Friend, use it, staple to my recipe.
If you are going to use the Water Profile Tool, you may want to google say a water profile for an APA, and create a new water profile for it like you did for your base profile. Use it as your target water instead of a particular city.
