I’m not sure why I didn’t do this sooner, but I finally went to the local home brew supply store and bought some Burton Salts (named after an English town that has a particular brew affected by its water supply – wiki). Home brewers use the salts to condition water to make ales in the style og Burton, but as a non-brewer you can dissolve the salts in water to make mineral water in your selzer bottle or sodastream.
Although I could have used the spreadsheet that the Khymos blog has (see this lengthy article) and made my own particular mix of salts and minerals, I decided to go the lazy route and just get Burton salts.
I may try the custom route later, but I was curious to see if the Burton salts would even work. They did. I can now make better mineral water and my hope is to convince someone to stop buying so many expensive bottles at the grocery store and to get a sodastream and salts instead. But we’ll see.
1 after putting in 1g of salts into 1L of cold water and
2 then after 5 mins of waiting (the water gets even more clear after carbonation)