I’m fortunate enough to have great (low minerals, minimal chlorine, no chloramine) water from the tap. I sent a sample to Ward a few years back and use a combo of BeerSmith and Bru’n Water to determine adjustments per recipe. Works great!
I build from 100% RO. I have been told that here in Cincinnati, we have water great for general brewing purposes. Seasonal changes and or different styles of beer should and do require different profiles to bring out their best. For me it’s easier to start everything with RO and go from there. Just my .02
Add me to the RO + BWS fan club. Solved so many of my brewing problems, and the additional attention seems to have helped me improve other processes. Best advice: have a plan, but don’t over think it. Start with a style profile, brew with it - and brew again with a slightly different one. Amazing the delta that relatively small changes can make between a Malty versus Dry profile can produce.
Our well water has ton of iron (could smelt ingots out of it), so our water softened tap has tons of salt. (screwed either way) I use RO water from the machine at Wally-mart but check it with a $10 pen-style TDS meter to make sure it’s maintained well. (TDS<20 ppm)
I have relatively soft well water, so I just use that as my baseline and adjust from there. If I had a significant amount of carbonates (or sulfate, or sodium, or another ion with significant flavor impact), then I’d probably use RO water and build it up from that.
I’ve found that our Michigan tap water is a pretty good starting point for brewing. I add some campden tabs to get rid of chloramines, and then fine-tune according to BrunWater - usually fairly minor additions depending on style and grain bill.
My Michigan tap water is terrible, highly alkaline, from wells. I use RO. I did a Helles recently that used 1 part tap to 8 parts RO. That gave a treated Munich profile, the beer is good.
I use tap water since our water is relatively low in everything except sodium and alkalinity. Basically I have to acidify for most beers, and a lot for pale beers. I use phosphoric. I then add brewing salts appropriate for the style.
pH 8.5
Sodium, Na 79
Potassium, K 2
Calcium, Ca 3
Magnesium, Mg < 1
Total Hardness, CaCO3 12
Nitrate, NO3-N < 0.1 (SAFE)
Sulfate, SO4-S 2
Chloride, Cl 17
Carbonate, CO3 9
Bicarbonate, HCO3 191
Total Alkalinity, CaCO3 172
Total Phosphorus, P 0.62
Total Iron, Fe < 0.01
I’d love to be able to use tap water. I don’t have an RO filling machine close by which means rather than paying $0.29/gal I’m paying $0.69 at the store. I’d rather pay $0.02 or whatever tap water costs. Unfortunately the water here is all surface water and we go through droughts in dry months so the mineral content varies widely across the year. It’s full of bicarbonate and just tastes terrible. I have an inline filter in my fridge for drinking water and a PUR on the kitchen sink and while both get the water to a semi-drinkable place I’d rather spend a few extra dollars when making beer to use the best water I can.
If I wanted to use the local water I’d still have to cut it with a softer water. I brew lots of lighter beers and the bicarbonate in the local water is just too much. I guess I could make extremely minerally water to try to reach a balance but that doesn’t seem like the best course of action. It’s sad, actually, because there used to be great well water locally. I have the water profile for brewing from a local brewery that existed pre-prohibition that pulled water from artesian wells. The city was so misguided in their belief in the endless water supply underground (like much of Texas at the time) that they implemented no conservation efforts. Unsurprisingly many of the wells dried out and as it turns out there wasn’t enough water to satisfy the city and surface water had to be created by damming the cesspools of the Trinity River.