Building Water Chemistry from RO for a Porter

I’m trying to figure out what to add to my RO water for a porter, and it seems like I need a high amount of bicarbonate. I know I can add bicarbonate by using baking soda, but how do I do this without overshooting my sodium?

There are several good programs/spreadsheets available online for adjusting water chemistry.  I don’t have the ability to post links but someone else will soon.  You’ll need to know your water volumes for mash and sparge.  Inputting your grain bill will also help with determining pH

My favorite is at brunwater.com

Don’t worry about the sodium content when you start with RO. The mashing water will have elevated sodium, but when the baking soda-free sparging water will dilute that content. The supporters version of Bru’n Water calculates the ending content.

Great, thanks guys! I will definitely be using a calculator.

Have fun with the water adjustment process.  It took me about 12 batches before I learned about managing water content.  It took my beers to the next level once I learned not to rely on what just came up from the well.