Well, you caught me regarding whose line of reasoning I've been following. Thanks again for your replies.
I don't know that Dr. Lewis invented it or named it as such but he might have done. I do know that he taught his students that their water would be what made their breweries distinct from others and that, therefore, they should brew with their water as is to make their beers really theirs.
I used to have access to a pro QC lab, and great pH meter, and used to check my pH every batch. I stopped when none of them were seriously out of range. Can't say I tried brewing a BoPils during that time, though I did do many blonde ales and stouts.
It certainly isn't so important to check mash pH once you have your recipe (including water treatment, if any) and procedures dialed in. There shouldn't be much batch to batch variation in pH just as there shouldn't be much variation in temperature. If you change malt suppliers or start using a new lot of malt from the same supplier or if the maltster switches from winter to summer barley then there may be a change in pH and if you catch this you can then compenstate in the next and subsequent batches.
I can remember chatting not that many years back with brewers from three Gordon Biersch stores about this and one of them said you home brewers worry about that stuff a lot more than we do. Moving forward to last fall I asked, at the Mid Atlantic MBAA meeting, for a show of hands from everyone who regularly checked mash pH and was surprised to see that perhaps 2/3 indicated they did. And one of the local Gordon Biersch guys asked for a pH meter recommendation.
I am very interested in seeing where we end up regarding water adjustment philosophy in brewing. I've seen too many radical turns in methodology over the years to completely buy that we have it right this time, when we thought we had it right last time, and the time before that. That's not to suggest I don't respect your work.
Mash pH is clearly a very important parameter - at least as important as temperature. It is very clear that if we want good beer we need to be attentive to mash temperature and it should be equally clear that we need to be attentive to mash pH as well. Many of us have observed the 'brighter flavors' effect of 'correct' mash pH. We have to allow that just as the correct temperature varies from style to style so too may correct mash pH.
The idea that mash pH is important is not new. There are lots of references to this idea in the literature. The difference between the even recent past and the present is that today technology has given us 3 gifts:
1. An affordable means of checking mash pH (i.e. inexpensive but accurate pH meters).
2. An affordable source of low ion water - the modern inexpensive RO system which allows alkalinity to be removed down to close to 0 (as opposed to about 1 mEq/L by lime or heating treatment) and the ability to put stylistic ions more or less where we want them.
3. Powerful desktop (or palm top) computing which puts even fairly sophisticated (iterative) algorithms for estimating mash pH into the hands of any brewer.
The combination of those two factors has led me to a somewhat skeptical approach to water adjustment.
Since it seems we are discussing whether elaborate water treatment makes better beer or not we have to point out that one cannot quantify 'better' without defining 'good'. There are multiple optimality criteria which may apply when brewing is discussed. To some home brewers (and perhaps some pros) the only criterion is whether the brewer himself likes the beers. To others it is whether the people to whom he offers his beers like them. The extreme here is the brewery investor who really doesn't care whether the Pils is pleasing to himself or the brewer as long as the customers buy it. To some, authenticity is most important (these would be the guys that do the most elaborate water treatment - trying to duplicate the ion profile of Pilzen water, for example. To still others winning competitions might be the criterion and I suppose we should add adhering to terroir - i.e. only brewing beers that work well with the water you have.
Clearly one's ideas about the best thing to do with one's water will depend on which of these criteria apply to him.