[Kit B]

Tristan, my insight into a lot of things brewing keeps evolving. I now think there is no need to add Mg since the malt brings enough into the wort. This is why I have been skipping Mg salts lately. 

Kai

I use R/O or distilled, for all my brews.
I've been skipping magnesium additions, lately.
And, there are no apparent problems or repercussions.
Flavor is great, yeast health is great.
I have seen no negatives, so far.

[Tristan]

could it be that the flavor came from the sulfate and not the added Mg?

Kai

I wonder if kilning/roasting malt to various degrees alter magnesium content?  Based on the article posted, it seems that an all malt wort has more than enough Magnesium.  Perhaps something else in their process (at Colin's brewery) changed that altered the flavor profile of the beer?

I did a bit of playing around with my water profile for an upcoming Oktoberfest.  During that time I began to doubt adding a minute amount of epsom salts would be a game changer in light of what the malt provides. 

Sometimes there is so much information available that there is a tendency to miss the "big picture."  Maybe this is an example?

Off topic, I'm transitioning from John Palmer's spreadsheet to Kai and Martin's spreadsheets.  You guys both did a great job of creating comprehensive tools.

[Kaiser]

I wonder if kilning/roasting malt to various degrees alter magnesium content?  Based on the article posted, it seems that an all malt wort has more than enough Magnesium.  Perhaps something else in their process (at Colin's brewery) changed that altered the flavor profile of the beer?

Unless you can make atomic fusion or fission happen you won’t change the Mg content in the malt .

Unless I can see for myself what Mg does to the taste and or yeast performance it remains speculation on my side that the amount we usually add doesn’t make much of a difference.

Off topic, I'm transitioning from John Palmer's spreadsheet to Kai and Martin's spreadsheets.  You guys both did a great job of creating comprehensive tools.

In the last few years there has been quite some progress in the understanding how grist and water settle at a given mash pH and how that pH can be affected, which is why updated tools are definitely helpful. I did however notice that Martin and my spreadsheet can come with widely different mash pH predictions in particular for mash thickness and alkalinity values that are not commonly used. Based on Martins comments only my acidity numbers were used there and not the other results of my research.

Kai