I too have found that mash pH changes substantially during the early stage of mash. I now delay my initial pH measurements until around the 15 minute mark since it is more stable by then. While I agree that a lot of conversion is occuring in the early mashing stage, using a decent brewing water calculator and adding the full prescribed dose into the mashing water is far better than dosing a little and waiting to see what the result is. With that incremental dosing, you really are hampering your results since the mashing pH is likely well off the mark.
Trust, but verify.
I agree with your assessment, Mr. Brungard. In fact, I use to add my full amount of lactic acid to the mash water while the water was entering my mash tun. Following this practice, I found my mash was far below the required mark. So I began reading various forums to see how others were measuring and began the procedure I’m following now as outlined above. Please note (with all due respect) that I was over-dosing my mash using Bru’n Water alone as my calculator. This is
NOT to say there is an issue with the spreadsheet. Instead, I’m certain the errors occurred as a result of incorrect input from me.
All that said, this post is the first time I have read that the majority of the conversion happens in the first 15 minutes. That seems unrealistic, but okay. What I have read was that the mash is most stable at 10-15 minutes and that’s the best time to measure pH. Note: using my current measurement method, my mash efficiency is generally 10-15 points above the mash efficiency predicted in BeerSmith.
So, I plan on brewing another Hefe soon. At which time I will resume my past practice and add acid along with the mash water following the calculations from your new version of Bru'n Water. As I stated above, I agree with your assessment. I simply need to be comfortable with the “trust” part so when I do the “verify” part I’m not inventing a whole new string of sware words.