Will do, next batch will get some in the starter and kettle. I did want to mention what I read this morning from John Palmer: "Zinc acts as a catalyst and tends to carry over into the succeeding generation—therefore it is probably better to add it to either the starter or the main wort but not both." (source) I guess he is referring to just supplementing zinc by it self and not necessarily our yeast multivitamin?
That could certainly be the culprit, this recipe called for a mash temp of 156F (I do maintain with RIMS)
Yes, ideally you should create your own thread for your own specific question. However, it's here already so I'll answer what I can. Others will likely be able to provide further detail.
I find the exact opposite - that is, Brewer's Friend is always more accurate to my final data than Bru'n Water. I've put the same info into both calculators, and my measured numbers are usually dead-on accurate when comparing to Brewer's Friend. I've noticed Bru'n misses the mark high every time. I've since gone exclusively to Brewer's Friend. But many people still use Bru'n with desirable results.
Also, you keep mentioning 5.2 for the mash, but that has been proven to not be accurate for measuring. The only mash pH you need to concern yourself with is the reference pH (that is, of the room temp sample you measured). That should be in the 5.4 - 5.6 range depending on style. I'd say you want to aim for the lower end for a Pilsner.
All that said, yes your mash pH will be higher than expected since you are doing such a thin mash. Brewer's Friend does indeed account for this. I input your data into the calculator and got an expected pH of 5.7. This is partially because you're adding slaked lime to the mash, with raises the pH. You should remove this addition from the mash and add it once you begin to boil, since it's only being used for mineral content. Doing that, you only need to up the acid malt to 2.4oz (which is 3.2%) and the pH dropped to 5.41. This sounds like it would work for you. Here's a link:
http://www.brewersfriend.com/mash-chemistry-and-brewing-water-calculator/?id=ZWQQ41X
pH estimates are obtained by considering the alkalinity of the water and the individual malts. If you have data on a handful of malts it is quite easy to build a spreadsheet which permits one to make pH estimates. After playing with such a spreadsheet for a while one gains insight as to what swings mash pH and what doesn't. Water alkalinity is a big driver.
The water's alkalinity is the main driver (raises pH). Colored malts contribute negative alkalinity (acidity) and are the second biggest factor). Calcium content has a small effect and magnesium an even smaller one.
With sauermalz the acid is lactic.
Yes, the flavors of lactic acid and the flavors of the malt it has been sprayed on or on which it has been grown. Some people prefer it over phosphoric acid because they want those flavor (both acid and malt) and phosphoric acid is quite flavor neutral in comparison to lactic.
That is easy enough to do based on the water alkalinity figure and the acid properties of the malts but as one seldom has accurate data especially on the latter it is, practically speaking, easier to make a small test mash and measure its pH for various levels of acid addition until the amount that gets mash pH correct is found.
The most important thing to understand about sulfate is that it is a personal taste. Many brewers (home and commercial) crave sulfate levels that exceed WHO recommendations for potable water. Others want as little sulfate as possible. You must find out where you fall on this scale. A good way to do that is to experiment with additions of gypsum in the glass to a moderately hopped beer.
It shouldn't but under under certain circumstances (high alkalinity water treated with acid to prevent membrane fouling with no means for the evolved CO2 to escape) it might.
RO water usually has a much lower pH (6's) because as it is mineral free even the tiny amount of CO2 in the air can acidify it.
Yes, that's exactly what it's for.
