Back to Shopping at

pH readings in brewing

Is there any good literature on when pH measurements should be taken or at least when they are more critical. I understand mash pH is a very important but I’m wondering what other times pH measurements can be helpful. I’m thinking the water book might cover some pH topics but I can’t recall of the top of my head.

I can’t think of any books or documents For ph readings other than mash, but I know some people track mash, pre and post boil and post fermentation ph. Hopefully someone more knowable about it will chime in.

15 minutes into the mash is what I’ve read. John Palmer has a book called How to brew. There is a lot of info throughout that entire book. I check my mash ph 15 minutes in. You’ll have to let your wort cool and the ph levels to settle before taking a reading, unless you have a meter that adjusts to high temps. If I need to lower my ph, I add lactic acid, stir, then check again in another 15. Obviously that would depend on the beer style your brewing.

1 Like

Careful there - temperature correction on a pH meter compensates for the temperature of the probe itself, which gives a different response at different temperatures. The pH of wort changes with temperature, too, in that it drops at higher temperatures. So you’ll get a more accurate reading of the wort pH at mash temperatures, but not at room temperature. And mash pH is generally normalized for room temperature. Example, if you’re shooting for a mash pH of 5.4, that’s at room temp. If you hit 5.4 at 152°F, your actual pH at room temperature will be higher than that.


Yeah one of the first books I grabbed before diving in. Although I don’t remember reading much about pH other than during the mash. Wondering about pH post boil, post fermentation and even in the finished product and why if any reason you would check it during those times. Picked up my Water book again and skimmed through the index for pH but it was mostly on mash and sparge water pH and adjustment.

Typically you don’t need to check pH after mashing. I’d say that mash pH is the most important one to hit, and after that you can pretty much ignore it.

Of course, there are some exceptions. If your pH is too high in the finished beer, it can reduce its shelf life over time. Not a big deal unless you’re a commercial brewer.

There are some who are of the opinion that kettle pH is very significant with hoppy beers. I believe that it does change the hop presence somewhat, but I don’t have enough experience to say how much of a difference it makes. I’ve been adjusting kettle pH prior to hop additions for the past year or so, but I can’t say definitively that it makes a difference. I think it does, but I can’t say for certain. Yeast can have a pretty big effect on beer pH during and post fermentation. Perhaps this is why certain yeasts are better at highlighting hop flavors?

If you make sours or mixed fermentation beers, wort pH is critical. Most people don’t, so most people don’t need to worry about it. But wort pH dictates which microbes can live in your beer, and even for the ones that can survive at lower pH, it changes their metabolism. It can determine whether your spontaneous fermentation is safe to drink, or whether it has the potential of killing you. But that’s a whole 'nother rabbit hole.

In general, though, mash pH is the one that all grain brewers need to worry about, and after that you can just let it go where it may.

1 Like

Porkchop, I stand corrected thanks dude

No worries! The temp correction claim on these pH meters is pretty darn deceptive.

1 Like

Haha yeah apparently. I own a ph meter, but I always let my wort cool to room temp for readings. Never actually put its claim to the test when the wort was hot.

Anyways back to MHALL2013s original question, The book How To Brew has info on chapter 15. Also, specific to your question, page 158-159 talks about mash ph ranges at room temp. Sorry but nothing on post boil PH. Enzymatic activity is mostly impartand during the mash and not post boil, that’s why most if not all references speak about mash ph at room temp and not wort ph post boil. There are several enzyme groups that take part in conversion of starches to sugars during the mash. Each of the enzyme groups are effected by mash ph and temps.

Yeah read the book of john palmer. Lots of info. I could be wrong. But you need a water report. Or a testing kit. To figur out. The ph level. Before you start. To adjust your mash water


So for instance, 2 days ago I brewed an IPA in the garage. Based on my most current water report coupled with the beer style, I added 6 grams calcium sulfate and 3 grams calcium chloride. My mash ph at room temp came out to be 5.7. I then added 3 ml of lactic acid and dropped the ph down to 5.3. I just called the city where I live and they emailed me the water report.

1 Like

pH readings should ALwaYS be taken at room temp. And something to keep in mind is that pH is constanmtly changing during the mash. It has a natural tendency to settle toward 5.4.

1 Like
Back to Shopping at