Okay, Larry, since you’ve asked, here’s my 2 cents…
For any beers that have no caramel or highly kilned malts, such as pilsner or perhaps cream ale or blonde ale, I find I need to adjust pH with a lot of calcium chloride, plus a little gypsum and/or a little acid. Carapils malt can also help. You always want to shoot for a pH of 5.2 to 5.4. The darker specialty malts are slightly acidic and get the pH down into the right range. But without sufficient quantities of any specialty malts, you can run into flavor or fermentation problems due to the high pH. This is a bit of a swag, but a couple of teaspoons of calcium chloride and a teaspoon of gypsum in 5 gallons of light colored beer won’t hurt a flea and will lower your pH considerably, as long as you start with your very soft water or RO or distilled water. Add to that a few ounces of acidulated malt as needed, and you’re basically guaranteed the right pH. Acidulated malt is normal base malt that is coated with just the right amount of acid to make easy pH adjustments. With experience you’ll know how much to use.
For anything else besides light colored beers, with soft water, it kind of goes based on the style. Red, brown, and black colored ales usually have enough dark roasted malts or caramel malts in them to bring the pH down appropriately if you start with very soft water. American styles can have very soft water, very hard water, or anything in between. IPAs usually have very hard water, so add a couple teaspoons each of CaCl2 and gypsum, or maybe more if your experience dictates. For other styles, you ask yourself, what’s the German water like? Or Belgian water or English water or whatever. Another swag, but with the exception of Pilsen which is extremely soft, European water overall tends to be pretty hard. If I’m making a European style beer, whether German or English or Belgian or whatever, I can either choose to use harder water on purpose, or use soft water and add a teaspoon of both gypsum and CaCl2, and call it good.
For really black beers like stout and porter, a very small amount of baking soda (maybe 3/4 teaspoon?) can help bring the pH up to the right range, since the black roasted malts can sometimes be a little TOO acidic. Ever get that odd vinegar/green olive flavor in a black beer? Yeah, I’m pretty sure that’s because the pH is way too low. Nothing a little baking soda can’t fix. Just don’t use too much or it will taste terrible.
With any salt additions, the best advice is to use restraint. When in doubt, don’t do any salt additions, and see how the beer turns out. 90% of the time, it will taste great without playing with salt. If not, you can dig into the water stuff more. However I think water additions are the very last thing that any homebrewer needs to be concerned with. First master every single other possible aspect of brewing. Then and only then do you really need to play with water.
Finally, I’ll say it again: don’t ever use very much Epsom salt. It ruins good beer. We don’t need no nasty magnesium in our beer. It’s just bad. Calcium chloride and gypsum will get you all the good tasting salts that you need.
