Acidity of dark malts

[oldjiver]

I live in a hard water area and have to adjust my liquor to get the correct PH with bitters. With stouts the guides all say that roasted malts increase the acidity of the mash, and I do find that I can just use water straight from the tap for these. I have never seen an explanation as to WHY roasting a malt makes it more acidic? Can anyone enlighten me please?

 

[BigYin]

This probably doesn't answer the 'why is it acidic' question, but it does go into a lot of detail and might help you with knowing which brews won't need treated water..

http://braukaiser.com/wiki/index.php?title=Beer_color,_alkalinity_and_mash_pH

 

[oldjiver]

Thanks Big Yin! I think the maths of that article are a bit beyond me, but there is some good information there. When I first stated brewing 35 odd years ago I got my local water profile and with (I think) Dave Lines book I experimented with litmus paper and got it right. As it always works Ok now just by boiling and adding gypsum for bitters I dont even bother checking. Never had a failure. (famous last words).