Is a pH above 5.4 ok?

A recent post on a homebrewing forum asked if comments by Alechemist's head brewer, John Kimmich, were wise to follow. John recommends that mashing pH always fall within a range of 5.1 to 5.3 at mash temperature, which is roughly equivalent to 5.3 to 5.5 at room temperature.

There is little doubt that he is correct for the beer that he brews. However, we need to recognize this for Alechemist: "We are currently focused on brewing one beer perfectly – Heady Topper". That is from their website.

I agree that you shouldn't allow room-temperature mash and wort pH to rise above 5.4 for pale beers. The flavors can quickly become muddy and less pleasant. In the case of Heady Topper, I can believe that targeting 5.3 (5.5 at room temperature) may be necessary for that lupulin bomb (yummy!). But that point of view for mash and kettle pH does not hold true for our entire spectrum of beer styles.

I and thousands of other brewers have found that some beers demand a slightly higher pH target in order to smooth and refine some flavors. Most pointedly, most porter and stouts are better when their room temperature mash and kettle pH is in the 5.4 to 5.6 range. I've even assisted a large regional brewery that was having flavor problems with their porter. After implementing treatment that boosted their mash pH, that beer was recently ranked as one of the top 25 porters in the country. It had been on its way to a thin and acrid death.

So, pH does matter and its incorrect to state that 5.1 to 5.3 is THE range for brewing. Its also important to note the temperature at which you are referencing pH. The proper breadth of the range is more like 5.1 to 5.6 at room temperature and there are subsets of that range that generally favor certain beer brewing. To blindly follow John's advice is akin to saying: "One size fits all". I'm hoping that this illustrates why we need to be a little more open and knowledgeable with respect to mashing and kettle pH.

Enjoy!