An automatic calculation of mineral additions would be a nice feature, but that assumes that every brewer has every mineral salt on hand and RO or distilled water for dilution too. Then add in the intricacies of an individual’s tap water and the problem becomes even tougher. This is a one-size-fits-all solution that doesn’t work in practice. In addition, the need to achieve exact ion targets is overkill. Brewing water chemistry somewhat closer to hand grenade than bullet. If you get components like hardness and alkalinity in the right range, the rest of the ions in the water profile can be 10 or more ppm off and you probably would not notice a difference.
I’ve programmed Solver routines in Excel and they are amazing in that they handle many variables and they find A solution. The problem is that when the number of variables increases, the number of possible solutions increase. Those solutions may or may not fit your needs and supply on hand.
Its not that hard to figure out the proper mineral additions via trial and error. But I can see that a newbie may not recognize that if the finished water profile needs more of a particular ion, which mineral do they add? With a minimal study, they would know which minerals add which ions. Then its an intuitive cat and mouse effort to chase down the additions that meet your goals and materials on hand.
Regarding the temperature effect on pH readings via pH strips. The pH of the mash varies chemically with temperature due to the change in dissolution of the hydrogen protons associated with the various compounds in the mash and wort. That pH change is known to occur and is proven.
The Colorphast strips are probably the best strips we have available for brewing use. One consideration is that the strip is saturated with wort immediately after its pulled from the mash. That chemical reaction mentioned above is reversible and therefore as soon as that saturated strip cools, it displays a room temp pH. If you were standing in a 150F room, then you might actually see the difference between a 150F and 70F pH reading. In a 70F room, the strip is going to cool almost instantly and provide you a room temp pH reading.
Regarding sparging water. All sparging water should have relatively low alkalinity. If you brew with water that has little alkalinity like RO or distilled water, you probably don’t need to acidify the water to bring the alkalinity down. In that case, the alkalinity is low enough that it does not consume a significant amount of the mash acidity and the mash pH does not rise significantly. The pH of low alkalinity water is not really a concern.
But, if the sparging water does have significant alkalinity (say > 50 ppm as CaCO3), then acidification is a very good idea. We use pH to describe our water condition, but its really the water’s alkalinity that matters. pH is just a loose allegory for the water’s alkalinity. We use this allegory because its easier and quicker to measure than alkalinity.
When the water alkalinity is high, the pH target that we need to shoot for in order to bring the alkalinity below 50 ppm is lower than what that pH target would be if the alkalinity was only moderate. In other words, we might have to target a sparge water pH of 5.5 if the starting water alkalinity was high, but we might only have to target 5.8 if the starting alkalinity was moderate. Again, the starting pH of the water isn’t all that important.
There are a lot of nuances to brewing water chemistry and it does take a while to grasp all the information. To help in your quest for knowledge, I’ve set up a Water Knowledge site at the Bru’n Water website. Do take a look at it and you should start to understand where you need to take your water.
Enjoy!