What wort pH is best for fermentation and beer quality?

We always talk about mash pH having to be 5.2 to 5.4 at 65 degrees celsius meaning 5.5 or 5.7 at room temperature (which is more or less pitching temperature).

What interests me is: what is the best pH for yeast/fermentation (unless strain dependent) and if pH can change as a result of the boiling stage because of things such as evaporation rate, hop rates, sugar addition, kettle finings,...?

If we are at 5.5 to 5.7 before boiling what could be (to what extent) could the pH change after the boil?

I'm just wondering if there is any point of discussing wort additions and talk about "fermentation pH" in the same way we are talking about "mash pH"?

Maybe there is no fluctuations in pH after mash out...

Finlandbrews said:

We always talk about mash pH having to be 5.2 to 5.4 at 65 degrees celsius meaning 5.5 or 5.7 at room temperature (which is more or less pitching temperature).

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We usually talk about suitable mash pH being between 5.4 and 5.6 at room temperature and don't tend to talk about what it is at mash temperature as we don't know what mash temperature is (beta glucan rest, protein rest, saccharification rest?).

Finlandbrews said:

What interests me is: what is the best pH for yeast/fermentation (unless strain dependent)

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It would be strain dependent and also depend on the style of the beer. The best pH for fermentation is the pH that produces the best beer. I know that's not much of an answer but as is the case with any brewing parameter one must experiment to find the best pH for a particular style and yeast. Some brewing books say the pH of wort entering the fermenter is between 5.0 and 5.2. These are probably reasonable values to start with. I've certainly done many a beer with a wort pH higher than this.

Finlandbrews said:

and if pH can change as a result of the boiling stage because of things such as evaporation rate, hop rates, sugar addition, kettle finings,...?

If we are at 5.5 to 5.7 before boiling what could be (to what extent) could the pH change after the boil?

Click to expand...

Yes, pH should drop appreciably in the kettle. I'd say down to at least 5.4 and ideally lower.

Finlandbrews said:

I'm just wondering if there is any point of discussing wort additions and talk about "fermentation pH" in the same way we are talking about "mash pH"?

Click to expand...

We do talk about kettle pH for certain. Fermentation pH we control we generally leave to the yeast with the idea behind kettle pH control being to make it easy for the yeast to set the pH where they like it. It is well known that the yeast will pretty much put pH at their desired level irrespective (but not completely so) of the pH of the wort they are given.

From Jamil and John Palmer they indicate mash ph of 5.4-5.8 at room temperature is ideal for enzymatic activity in the mash, while mash ph of 5.2-5.6 at room temperature is actually better for flavor stability...

Suggest you read:

Yeast: The Practical Guide to Beer Fermentation (Brewing Elements)

Water: A Comprehensive Guide for Brewers (Brewing Elements)

Also, lots has been covered here in the forum:

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