Melanoidin malt and ph

I’ve used brunwater for all my brews- always nailing ph. Recently I’ve used melanoiden malt at 12oz in my 12.75lb grain bill. Brunwater calcs my ph at 5.4, and twice now using melanoiden my ph is off and reads 5.2 in mash. I’m having to add a gram of baking soda to bring it up to 5.4.

Anyone know if melanoiden in mash is more acidic than the crystal malt selection used in mash prfofile? It’s the only variable I can think of.

feeling like i’ve stumped the forum…Martin-hopefully you see as you usually know the answer!

what’s the SRM on the melanoiden? did you enter it with the correct color and type? (Roast vs crystal)

yeah entered it at 27 - i used crystal, but just went back and changed it to roast to see the difference. it only chnages from 5.4 to 5.34. actual mash ph is calc at 5.2…still way off.

He answered the question a few years ago (https://www.homebrewersassociation.org/forum/index.php?topic=6016.95;wap2) and as he explained, Bru’n water identifies melanoidin malt as a crystal malt.

as i thought…however still cant explain the ph shift vs. brunwater calc.  might go down as an unsolved mystery.