Mash pH adjustment


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Feb 22, 2015
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Just getting started in all-grain work. Think I understand the mash pH is desired to be in the 5.2-5.4 range. At what point does one check the pH? Immediately post dough-in? Later? Should one adjust the water before the mash stage?
Just trying to get a handle on the mechanics.

I never need to adjust the PH but if you live in a hard water area (usually indicated by limescale around taps) you might need some adjustment. The best thing to do is find out your water profile from your water supplier and work out the adjustment needed. The second best thing to do is a small mash and take a Ph reading from the wort during the mash but let the sample cool to 20c first, You can then use this reading to work out any adjustments needed if any are. I always get between 5.2 and 5.26 and I'm in a soft water area.
I adjust after I get my recirculating smooth right after dough-in, 88% phosphoric acid for me, most states have around 7.5 ph drinking water so a Campden tablet and a cupful is all I need
Thank you, Kindly, for the responses.
Have a sample in for analysis at present. Will see where that takes me.

Thanks again!

Well, you'll want one from before and afterward, so you know exactly what's going on and what needs adjusting. I stopped taking pH readings for any brews I've done before, or any that were even close to ones I had brewed before. IF I'm doing something completely new and different with malts I haven't used before, I'll take a pH reading. I mainly only use pH readings in mead & wine making, though. Beer has never given me any far. We have moderately hard water here, but nothing like the places where limescale kept building up on fixtures. It takes about 10 years to even notice some slight accrual of deposits.
Before and after what?

Ph of your tap water is almost irreverent, and a performing a water analysis on your wort is a bit well, among other things, too late.

Sorry for being a troll, but I just can't make heads or tails from this post.
Re: Before and after what?

surfmase said:
Ph of your tap water is almost irreverent, and a performing a water analysis on your wort is a bit well, among other things, too late.

Sorry for being a troll, but I just can't make heads or tails from this post.
Translation: you really shouldn't have to worry about your water pH, your mash pH, or your final pH (to see what changed) if you're using modern modified malts, and nothing incredibly crazy. As long as you keep your temps correct, nobody should really be having any pH issues. As long as their water isn't crazy hard or soft, most water will fall into the proper pH range with no interaction from the brewer.
A bit late to the party but here's my take: Mash pH is important for conversion, yet you need to let the enzymes do their work to buffer the mash. I wait about five minutes after dough-in then take my pH and temperature. At that point, I still have time to adjust the pH if needed.

Your tap water pH is mostly irrelevant: What matters are concentrations of various ions, specifically calcium, magnesium, and any of the carbonate species (alkalinity). Although imperfect, residual alkalinity is about the best predictor of where your mash pH will end up. John Palmer has the formula in his book and baked into his water calculation spreadsheet.
An old thread, but I am new and learning...
I don't think that the OP will mind me taking this in a different direction, as he appears not to be active since posting this thread a little over 2 years ago.


Is it the calcium, magnesium, and other minerals which cause higher alkalinity?
Is it the grains interacting with these minerals that can bring counteract the alkalinity?

My first handful of brews were done using softened water. At that time my Star-San mixture stayed nice and clear, but the brews were, okay, but not great. Now that I am using hard water, and our water is pretty hard. The brews (not tasted yet), sure look a lot better, but my star-san solution is very milky. My understanding is that this is caused by the alkalinity of the water, in that star-san is acid based, and the milky color is an indication that the solution is now more alkaline than acidic. Sorry to use the work alkalinity 3 times in one paragraph... doh! make it 4.

Maybe I use the hard water for the brew, and the softened water for my cleaning solution...

I have ordered a Ph meter to put into use with my next brew day so I can get some real data.
I don't have information on my water profile at this point.

Okay, lots of ground to cover there:
- Carbonate causes alkalinity in water. Calcium, magnesium and other metallic ions are along for the ride when it comes to alkalinity. Carbonate takes up hydrogen ions to form bicarbonate, the only way it's soluble, and that's what causes the alkalinity.
- Phosphate in the grains interact with calcium, magnesium and so forth to reduce the alkalinity of the mash (make it more acidic). You can add calcium and magnesium to reduce the mash's alkalinity, to a point. Here's where the concept of residual alkalinity comes in handy.
- Star-san is phosphoric acid and a surfactant. Mixed with distilled water, it'll last nearly forever. Mixed with hard water, you get calcium phosphate, a mineral known as apatite. It is insoluble in water. When your star-san turns cloudy, it's no longer effective. Toss it and start over.
- Softened water exchanges sodium for calcium. It forms salt water, basically.

Until you know what's in the water, I'd recommend buying reverse osmosis (RO) water and adding salts for brewing. Use distilled water for the Star-San - I mix it up four gallons at a time and keep it in a food-safe bucket, ready to use. As for the softened water, use it for cleaning, watering the grass, etc.
I feel a Brulosophy inconclusive experiment in the making.
They've done a few and haven't been able to find a difference.
I've participated in a few. My baseline belief after all the tests and lack of significant results is that while a lot of stuff is important when you're making thousand barrel batches, at our scale there are a few really important variables. And beer is difficult to mess up. We have adequate sanitation easily achieved. We have access to ingredients that would be considered miraculous 100 years ago. We have pure-culture yeast, refrigeration, clean sources of a lot of heat. In fact, things are so good we are looking to marginal improvements like salts in water or obscure mashing regimes to make our beers better. We have the major factors in brewing so well under control even at homebrew scale, it's hard to find a significant result.
Brewing salts made a surprisingly noticeable difference but PH showed no real impact.