Author Topic: Residual Alkalinity  (Read 1457 times)

Online gman23

  • Official Poobah of No Life.
  • *
  • Posts: 3518
    • View Profile
Residual Alkalinity
« on: March 11, 2015, 07:38:30 PM »
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
On Tap/Bottled: Hopfenbier, Kurbis Marzen, Red Rye, Vienna Lager,      

Fermenting: Imperial Porter
Up Next: Maibock, Braunbier

Offline AmandaK

  • Senior Brewmaster
  • ******
  • Posts: 1850
  • Redbird Brewhouse
    • View Profile
Re: Residual Alkalinity
« Reply #1 on: March 11, 2015, 07:54:10 PM »
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!
Amanda Burkemper
KC Bier Meisters Education Director
BJCP Assistant Education Director
BJCP Master/Mead

Redbird Brewhouse - There's Always a Project
Our Homebrewed Wedding, AHA Article

Online gman23

  • Official Poobah of No Life.
  • *
  • Posts: 3518
    • View Profile
Re: Residual Alkalinity
« Reply #2 on: March 11, 2015, 07:58:00 PM »
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.
On Tap/Bottled: Hopfenbier, Kurbis Marzen, Red Rye, Vienna Lager,      

Fermenting: Imperial Porter
Up Next: Maibock, Braunbier

Offline AmandaK

  • Senior Brewmaster
  • ******
  • Posts: 1850
  • Redbird Brewhouse
    • View Profile
Re: Residual Alkalinity
« Reply #3 on: March 11, 2015, 08:05:07 PM »
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.
Amanda Burkemper
KC Bier Meisters Education Director
BJCP Assistant Education Director
BJCP Master/Mead

Redbird Brewhouse - There's Always a Project
Our Homebrewed Wedding, AHA Article

Offline HoosierBrew

  • Global Moderator
  • I must live here
  • *****
  • Posts: 13030
  • Indianapolis,IN
    • View Profile
Re: Residual Alkalinity
« Reply #4 on: March 11, 2015, 10:14:37 PM »
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. 
Jon H.

Online hopfenundmalz

  • Global Moderator
  • I must live here
  • *****
  • Posts: 9008
  • Milford, MI
    • View Profile
Re: Residual Alkalinity
« Reply #5 on: March 11, 2015, 10:36:26 PM »
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
Jeff Rankert
Ann Arbor Brewers Guild
AHA Governing Committee
BJCP National
Home-brewing, not just a hobby, it is a lifestyle!

Offline Wort-H.O.G.

  • Official Poobah of No Life.
  • *
  • Posts: 4439
  • Play Nice
    • View Profile
    • Harvey's Brewhaus
Re: Residual Alkalinity
« Reply #6 on: March 11, 2015, 10:37:12 PM »
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.
Ken- Chagrin Falls, OH
CPT, U.S.Army
https://www.facebook.com/pages/Harveys-Brewhaus/405092862905115

http://braukaiser.com/wiki/index.php?title=The_Science_of_Mashing

Serving:        In Process:
Vienna IPA          O'Fest
Dort
Mead                 
Cider                         
Ger'merican Blonde
Amber Ale
Next:
Ger Pils
O'Fest

Offline Frankenbrew

  • Brewmaster
  • *****
  • Posts: 680
  • South Shore Brew Club, SE Massachusetts
    • View Profile
Re: Residual Alkalinity
« Reply #7 on: March 11, 2015, 11:21:24 PM »
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.
Frank C.

And thereof comes the proverb: 'Blessing of your
heart, you brew good ale.'

Offline HoosierBrew

  • Global Moderator
  • I must live here
  • *****
  • Posts: 13030
  • Indianapolis,IN
    • View Profile
Re: Residual Alkalinity
« Reply #8 on: March 11, 2015, 11:29:06 PM »
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.
Jon H.

Offline quattlebaum

  • Brewer
  • ****
  • Posts: 370
    • View Profile
    • Wildhops
Re: Residual Alkalinity
« Reply #9 on: March 11, 2015, 11:30:59 PM »
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:)