[Iliff Ave]

Be gentle. I am a water/chemistry novice.

Can some help me understand or provide some good reference for understanding residual alkalinity. I haven't really be paying attention to it but my last batches seem to have negative RA values. Is this bad? I have noticed anything objectionable in the final product

[AmandaK]

I just explained this to my husband last weekend, so here's hoping I got it right.

RA is the measure of how hard you'll have to "push" to get the mash pH where you want it to be. You can push with grains (color dependent) or water adjustments. If you have a high RA, the less the water wants to be pushed to the desired mash pH, which is why is requires more outside force to move.

Section 2.4 here: https://sites.google.com/site/brunwater/water-knowledge Which is going to be better than my explanation by a long shot!

[Iliff Ave]

Thanks. I was actually just reading that tab in the spreadsheet. So RA is more important for your existing water and not your adjusted water? For example, my existing water RA is 27 and my adjusted water RA for a pale ale is -38.

[AmandaK]

Thanks. I was actually just reading that tab in the spreadsheet. So RA is more important for your existing water and not your adjusted water? For example, my existing water RA is 27 and my adjusted water RA for a pale ale is -38.

Yes and no. But I'm not qualified to explain why - I barely just understand it myself and don't want to lead you astray.

[HoosierBrew]

Yeah, looking forward to hearing Martin weigh in.  Supposedly, RA is partly a measure of water hardness and since RO or distilled have basically no hardness, my understanding is that it's not as big an issue (in and of itself) for brewers that use distilled or RO, above and beyond the need to hit a good pH. But I could be wrong. 

[hopfenundmalz]

Who said nevatve RA is bad? My crisp lagers always ha 've a negative RA.
Alkalinity is the bad item, hardness is good (Ca and Mg). Edit - up to a point.w

[Wort-H.O.G.]

Yeah, looking forward to hearing Martin weigh in.  Supposedly, RA is partly a measure of water hardness and since RO or distilled have basically no hardness, my understanding is that it's not as big an issue (in and of itself) for brewers that use distilled or RO, above and beyond the need to hit a good pH. But I could be wrong.

+1 been my understanding also. getting the correct pH can result in very different RA for each brewer, based upon their starting water used....both resulting in great beer.

[Frankenbrew]

Who said nevatve RA is bad? My crisp lagers always ha 've a negative RA.
Alkalinity is the bad item, hardness is good (Ca and Mg). Edit - up to a point.w

Yes, most of the beers I have brewed lately have been light colored, and the target water (using Bru'nwater) is always negative, including IPAs.

[HoosierBrew]

Who said nevatve RA is bad? My crisp lagers always ha 've a negative RA.
Alkalinity is the bad item, hardness is good (Ca and Mg). Edit - up to a point.w

Yes, most of the beers I have brewed lately have been light colored, and the target water (using Bru'nwater) is always negative, including IPAs.

+1.  Opposite for dark beers that need alkalinity to hit good pH.

[quattlebaum]

So from my understanding there is an interplay between C02 and chalk solubility, water alkalinity and water hardness which combine to affect mash PH and is termed “Residual Alkalinity”. Some German brewing scientist by the name of Paul Kolbach discovered that we as brewers can manipulate mash PH by using this RA.  It’s basically “Alkalinity” left over after some of the other ions are used by the malt. I may be wrong cant wait to here what martin says:)