I'm fairly new to brewing and for the first half-dozen batches I have just used packets of Burtonizing Water Salts to treat my water picked up at my local homebrew supply store. So far, per that store's owner, I've added 9 grams of the salts to my boil when there's 15-minutes left. Beers have turned out pretty decent.
I now want to level up my water treatment game a bit. I'd like to start targeting specific water profiles based on the beer I'm brewing. To make things super simple, for now, I am using distilled water purchased in gallon jugs from the grocery store. I will likely upgrade to my own RO system based on the popular YouTube video by Brew Cabins, or do something similar. But I'm not there yet: for now, I'm going with distilled water as the source. Why? Because I can control it and I know the salt and mineral levels of my source water (zero for everything!). Its a constant that I can depend on. I live in a very small town and had 2 separate Ward Lab readings come back significantly different just 3 months apart from one another, so I do not want to trust my tap water at this moment in time.
So then, going to Brewer's Friend Mash Water Treatment Calculator, I punch in my water volume and source water numbers (0 for everything since its distilled); and 6.2 for the pH since I've read distilled water is typically around there. I have a digital pH meter on order and will use that and make corrections to the guesstimate of 6.2 moving forward.
I'm going to try a Wee Heavy, and so I've selected the Edinburgh water profile for Scottish and malty ales. It gives me the PPMs for 3 cations and 3 anions that I need to target to achieve an "Edinburgh" water profile, and more importantly, computes the delta for each brew salt. Now the alchemy begins.
In the Salt Additions section I play around with the number of grams for various salts. I have read in several places that you want to target being +/- 20 PPMs for each salt (you may disagree with this, and if you do, I'd love to hear about it and find out why!).
And, after doing some alchemy and playing with additions, I've found that by adding a certain amount of Gypsum, Calcium Chloride, Chalk and Baking Soda that my "deltas" are all within +/- 20 ppm of Edinburgh. I think this is mission accomplished (maybe?)! What's more, the water report shows all these additions as being within a safe/normal range.
So to begin with, seeing how this actually is my first rodeo, I'm not sure if I'm using the tool correctly or not; if I'm not, then based on my description above I'd appreciate input on what the correct way of using the tool actually is!
Assuming my process above is more or less correct, then if I am using the tool correctly, how and when do I add these salts? To the boil? 15 minutes out from the end of the boil? Just dump them in the boil and stir them in? Or is the process completely different?