I was brewing all grain czech pilsner using multi step mash (122F protein, 149F beta, 158F alpha, 170F mashout). My well water is alkaline at 110 ppm as CaCo3 so I used a 50/50 mix if distilled water and well water. I anticipated lactic acid addition to get wort pH in desired range. I took pH measurements shown below. My question is why did the pH go up at beginning of Beta rest? I am using bluelabs combo meter calibrated at 7 and 4 prior to using. I cool the mash in heavy ceramic coffee cups from freezer prior to testing. I let it line out for a while too before taking reading.
Ph 6.1 5 min into protein mash added 1ml lactic acid after this
Ph 6.0
Added 1 more mil for total of 2mls
Ph 5.7 7 min left to 20 min protein
Added 1 more mil for total of 3mils
Ph 5.5 lets hold here and see what happens at higher temp
5 min into the 30 minute beta pH 5.9
Added 2 more ml for total of 5 mls
At 20 minutes left now ph 5.6
This is interesting. IIRC Kai Troester (Braukaiser) observed this but to my knowledge was unable to find the reason.
What grains were you using that you felt the need for a multistep mash? I’ve done a multistep mash for practice but most modern grains are have diastatic power so I never feel the need for a multistep mash.
A lot of fun info here on pH and the mash
http://braukaiser.com/wiki/index.php/Mash_pH_control
Doing a stepped mash is quite easy with an electric kettle. I don’t think I ever found any change in my brews… BUT…
Doing a Beta rest at 140F… then an Alpha rest at 158F… I find my Final Gravity ends lower each time I employ it… I don’t do every brew with that… I do like using that method for a lighter brew… Stomping down the water is another one I get a benefit from with the lighter brews…
My water does change… so monitoring my pH is standard practice…
I am going to do a decoction mash soon… Ive not ever tried that…
Sneezles61
I am using the northern brewer all grain czech pilsner kit. It has 9.5 pounds of German pilsner malt and 0.25 pounds of weyermann carahell. Kveik lutra yeast @69F. I agree I wondered myself what benefit to multi step mash with most modern malts. Instructions gave multistage mash as option A. Since now brewing in basement designed for beer making I wanted to try it out to see how well I could control without wind effects that I get outdoors. Really much better temp control. I was going to just use distilled water for it all and add some calcium chloride but changed my mind at last moment. Next time all distilled water with CaCl2. At some point I may try lime addition to reduce the alkalinity after I get set up for good alkalinity measurement by titration with acid.
I followed your link and its interesting and loaded with details. I found the plots of pH vs various malts used insightful. Its an educated shot in dark as to what the pH will be during the mash when first time brewing a batch.
pH is not stable during the mash. There are dozens if not hundreds of chemical reactions going on.
And as I am sure you figured out, you definitely did not use near enough acid at the beginning of the mash. It takes a lot of stirring and time for that to all equilibrate out.
yes I was adding the acid gradually so as not to overshoot. Also I was not sure at what temperature the reaction of the phosphates in malt with the Ca in water occur. I later added more lactic acid for a grand total of 7 ml to get to 5.3. It later went up to 5.5 then finally settled out at 5.4. I eventually will get a 2 decimal point pH meter so I can have more confidence in knowing a 0.1 change detected is real.
I use brew in a bag and bob the bag up and down to stir the wort so my thermocouple reads temp well. I more or less do this continuously when not measuring stuff. I also do at least two bag lifts and let it drain for one minute during each step then punch the bag back down open it and stir up the grain well so its wet like a slurry(5.5gal water in mash 9.75 lbmalt). At mashout I drain the bag well in a turkey fryer insert held up with inverted bowls in large container. I then slowly and intermittently rinse the grist for 3 batches(170F 1.5 gal total 3 rinses). I generally add the first two rinses to the boil but the third rinse I boil in a separate pot. If needed, I add the third rinse at end of boil. OG 1.06 vs 1.047 recipe called for in this case.
The reaction rate between an acid and base like HCl and NaOH is one of the fastest chemical reactions. However, yes the gazillion other reactions effecting (or is it affecting?) pH may take time.
