Mash pH and Clarity for Pale Ales

[Pappers_]

Does mash pH impact the final clarity in a pale ale? Would be grateful if someone could give me a brief primer on mash pH and clarity. Thanks in advance.

 

[ESBrewer]

The more acidic the wort, the more protein tends to be insoluble. Thus, during boil phase you lose more protein which MAY result in less haze because protein is a major contributor in haziness. In addition, the positive net charge of proteins caused by low pH makes them interact more tightly with certain negatively charged finings such as carrageenan(active compound in Irish moss / Whirlfloc). Also, a pH all too high may extract more polyphenols from malt that contribute to (chill) haze.

 

[Pappers_]

Great, thanks!

 

[ajdelange]

In general, no. Note that the valid comments in No. 2 reflect conditions in the kettle and fermenter. Set mash pH in the 5.3 - 5.5 range to get the desired mash chemistry but check that knockout pH is in the low 5's by, e.g. making sure sparge water is at mash pH and adding acid to the kettle wort if necessary.

 

[couchsending]

Isn’t kettle pH of 5.2 optimum for protein coagulation?

 

[ESBrewer]

Isn’t kettle pH of 5.2 optimum for protein coagulation?

Yes, the eventual boil pH is probably the most important factor for coagulation, not the pH of the mash itself. ~pH 5.2 is considered an effective pH for protein coagulation without sacrificing too much hop alpha acid utilization so it can be seen as some sort of sweet spot. After all, brewing is all about compromises between many factors. According to some sources, average isoelectric point of wort proteins would be even lower (~pH 4.9) and it is thought that at isoelectric point, the proteins that lose their native structure in the heat of the boil, would interact and clump together most effectively (because repelling electrostatic forces between molecules would be weakest at pI). Thus a solid trub gets formed. During boil, for several reasons, pH tends to drop slightly, maybe 0.1-0.2 units.