Are there changes in brewing practices that can utilize existing water profiles to get the desired brew profiles without starting with distilled water.
Absolutely. You give me a good lab report on a source water and a good ion profile for the desired brewing water and I can come up with additions that will give a darn close match. But the additions will have to include RO water if any ion in the target is at a lower level than it is in the source (exception: calcium, magnesium and bicarbonate can be removed by other techniques but then you need a new analysis to determine how effective those techniques were - dilution with RO is much simpler) and carbon dioxide if any adjustment in alkalinity level is desired. So now you have water identical to what the brewers of Helles in Munich had. Do you know how they treated it if at all? IOW it's not enough to reproduce the water of the city in which the beer was invented, you also must know how to use it. In most cases with a carbonaceous water the first step in brewing is to decarbonate it. There is little point in increasing alkalinity (messing with CO2 sparging) only to turn around and have to undo it (decarbonation by boiling or lime treatment).
I mentioned "good" reports and good profiles. There are lots of bad reports out there and even more bad profiles. Bad here means that the charges on the cations and anions don't balance. In a water report on a particular sample (such as a Wards report) lab errors result in small imbalances which can be ignored. More troublesome in this regard are municipal suppliers reports in which you are almost never given the results of an individual report but rather the averaged (over weeks, months or years) values. Average values do not necessarily balance - in fact they probably don't. The widely published profiles are, in general, atrocious in this regard.
To figure all this out there are, of course, spreadsheets which perform the intricate bookkeeping and calculations required. Most completely ignore the question of balance and if fed an unbalanced profile result in something that can send you off into left field. The new Bru'n water spreadsheet does calculate the balance in the report you enter and in addition has a library of
balanced target profiles.
After 20 years of fiddling with designing water I have decided/discovered that it is, in general, too much trouble though still fun to play with. A simpler approach is to start with low ion water and add what you want skipping bicarbonate/carbonate except in cases where mash pH is demonstrably too low as determined by accurate (no pH test strips) measurement.
For a home brewer to be adding this much cost to a batch of beer is a matter personal choice, I would not think this could be an option for a commercial entity. I understand that some breweries will stick to certain styles based on their water profile and I imagine an answer to this could get very involved.
It absolutely is an option and cagy commercial brewers use it. The economies of scale reduce the operating cost of producing a gallon of RO water to pennies. There are, of course, capital costs but these would be modest compared to, say, the cost of obtaining enough kegs to support off premises draft sales.
With the help and direction I have gotten here I have started to play with different spreadsheets and calculations to get a desired calculated mash PH and mineral profile. If I were to try to modify my process to utilize what I have instead of making additions - What would/ could I do? I am in a different situation than KPatton as I have 'soft' water and I know that I am asking questions that are (far) above my brewing needs but I am interested to know.
The obvious answer is to stick to Bohemian pilsners but I'd say be bold - try an IPA with soft water and a stout and .... You may be pleasantly surprised by the results. It probably really makes more sense to start with the Primer guidelines and reduce salt additions as you brew different batches of the same beer. IOW, a Burton style ale would initially be done with extra gypsum and some calcium chloride and the result would be a beer that nominally resembles a traditional Burton ale (if you taste the stuff that is exported these days you know that it's not brewed with water as gypseous as the traditional). If you brew it with softer water it will be mellower, sweeter, smoother and probably considered better by most drinkers but you might not like it and you might get dinged in a competition for not cleaving to the style guidelines.
As for the process proper i.e. things like differing fermentation temperature, different mashing temperature etc. - no, there is nothing you can do there to make a soft water Burton Ale come out like a traditional Burton Ale. One thing that may be new to you is the use of acid or acid malt to set mash pH. This is critically important. Purchase and use of a pH meter is a very important part of all this.
Given what I said about soft water and Martin's comment in #36 I guess I should point out that when I advocate starting with "soft" water I mean soft (DI, RO) water. But the guidelines in the Primer advocate adding some calcium chloride to this soft water. I suspect the chloride of being of as much benefit through organoleptic taste enhancement as the calcium is through improved yeast performance, break formation.... That said I'll note that AFAIK, Pilsner Urquell and Budvar are brewed with very soft (but not RO/DI soft) water. I supplement my RO water with CaCl2 when I brew Boh. Pils and, as I have just found out that I am using anhydrous calcium chloride (having assumed for years that it was the dihydrate) I am using more than I intended. The beer is good, though.