Most amateurs start with RO water for their brewing and are pleasantly surprised with their experiments. Calcium Carbonate/acid blend to alter the pH is good enough for 90% of the brewers.
It’s only after you get into the zest of perfection, do you realize the importance of water chemistry. Which is a subtle but powerful tool for any brewery arsenal.
Common issues faced:
1. IPAs are not hoppy enough. (add sulfate)
2. Your light beers are great but dark beers not so much. (need to use hard water—- Ca, MG salts)
3. pH to be regulated (which most people realize after their 2nd batch or so)
That being said, be mindful of a couple of aspects one should be mindful when using chemicals:
1. Keep them away from kids & pets. Always label and airtight.
2. Be sure of the molarity (strength) of the salts before you add. Calcium chloride will soon turn into an aqua solution once opened. So I dilute it to a known strength the moment I open the packet. Similarly some salts hydrates lose water during storage and hence become stronger. Check the storage instructions and if needed make a solution of known strength when fresh.
3. Some salts have varying degree of hydration. Google for adjustments in the ratios (molar weight) to tweak your recipe
4. Keep logs records and notes.
5. Although recipes call for de-ionized water/distilled water. I found that RO water is typically good enough. But do your experiments beforehand.
6. Most chemicals are available in four different grades. Technical grade (cheapest), food-grade, Laboratory grade and Pharmaceutical grade (called IP which is most expensive). Understand the difference between % purity, permissible levels of impurities and nature of impurities between the four before you go on a scavenger hunt to find your missing reagent.
7. Most chemicals have a simple titration based method to test the purity. But unless you have a chemistry background or you are planning to pursue this commercially, it will be an overkill.