When to check mash pH

I hear a lot about how important it is to for your mash pH to be in the proper range (approx. 5.3-5.6).  So when do you check?  Right after you ad your grains to the strike water, after ten minutes, half way through?  It seems like every interview and every article I read simply says check your mash pH.  My tap water is around 7.3 year round.  I’ve never checked my mash pH but every local brewer I talk to says we have great water and they don’t make adjustments.

Great question. There must be a time between when mash in water pH transitions into mash water pH. Brewnwater gets me in the 5.2 range with 100% RO and salts every time I check. But I still check. What is the best time to check pH?

So you are adjusting your RO strike water differently every time based on your grain bill?  Do you ever check your strike water pH?

You need to stir the mash gently, somthat the temperature is even and you don’t have dough balls. Check mash temperature and adjust. That takes me about 10 minutes. I pull a sample and cool it, then check pH. So it is close to 15 minutes after all of the strike water is in.

Water pH means very little. Mash pH means a lot.

No water is good for all beer styles. I have heard that too around here if the brewery is on the Detroit water system. That water comes from Lake Huron or the Detroit River. It has moderate alkalinity, and does not make a crisp Pilsner. It does make good Amber colored beers. The roasted grains used in stouts are acidic, and might drive the pH too low with that water. Google Brunwater and read the water knowledge section.

Do any of the breweries around you use Gypsum or Calcium Chloride? When in a brewery, I look around, and often see 50 lb. bags of those. The Calcium addition from those two salts lowers the mash pH, often into the correct range.

My experience is that you really need to wait at least 10 minutes or maybe 15 after mashing in before you get an accurate reading.  Before that, things are still equilizing in the mash.

I always wait 10 min and cool the sample. I’m only doing a 20 minute mash on most beers so I have too cool it as quickly as possible. fortunately I very rarely ever have to make corrections.

I think we need to clarify that you’re doing a 20 min. mash in a commercial situation.  Mashing in an lautering take a lot of time and you’re still in conversion range. (Am I interpreting you correctly?).  Most homebrewers will want to mash for longer than 20 min.

I think you could get by mashing 20 minutes on a small batch too. granted, I do vorlauf for another 20 minutes but I raise my temp up to about 156-158 and I’m getting 90 efficiency. One of you should experiment with a 20 minute mash.

I have…20 min. mash followed by 20 min. boil.  Worked fine, but I prefer the extra fermentability from a longer mash.

Definitely don’t check mash pH in the first 10 minutes. Those reactions take a little while to occur. The pH will change during the course of a mash. It is the final pH that’s most important.

It’s also really important that the brewer mix all the minerals and acids into the water before adding the grain. It’s really hard to mix all that stuff together evenly otherwise.

Given the prevalence of mediocre beer from various brewpubs, it should be no surprise that many brewers don’t adjust their water. Don’t be one of those brewers.

Fantastic Question.  I’ve been trying to figure this out myself…

My theory (and it may be incorrect) is that I just try to get close to my “ideal” mash pH during the Mash with precise adjustment done pre-boil.  A limitation of my “brewhouse” (I use Igloo coolers to mash + sparge with) is the inability to adjust temperature during the Mash.  As a result, it’s more important for my equipment + processes to ensure a stable temperature during the mash and nail pH after.  With that being said, I do check the pH of my tap water and record my LA addition to Strike Water before brewing and log it for every single brew.  That does help me make a very educated guess how much Lactic Acid to add to the Strike Water in order to get me close to my ideal mash pH (this is especially true if you brew the same recipe a few times).  I check a pH @ 15 minutes into the mash, and at the end of the Mash.  In my experience, I don’t get much difference between 15 and 60 (or 90 minutes if I’m mashing very low for Belgians) minutes, especially with low lovibond malts.  At most, a 0.1 pH change.  Sometimes up to 0.3 with darker malts (I would probably check later with darker malts, i.e. in porters/stouts).

After I’m done with my Vorlauf, I always check my pre-boil gravity (be sure to adjust gravity for temperature at this stage- I use brewersfriend) and adjust to Goal Pre-Boil Gravity.  I know my efficiency very well and if anything, I just have to add a little bit of Water.  After the Gravity adjustment, I’ll then take a pH reading and dial it in with LA to within 0.05 of my Goal (I use a MW102 pH meter, always calibrated at the start of the brew day).  I shoot for pre-boil pH of 5.2 with light beers (Hefe, IPA, Belgian Blonde/Tripel) and up to 5.5 with darker beers (Porter/Stout).  I usually shoot for somewhere in the middle if I’m brewing a beer with an SRM inbetween (i.e. Dubbel, Dunkelweizen)

I take my mash pH reading at 30 minutes into the mash. (typically 60 min mash).

Y’er darn tootin’!!  Give 'em Hell Harry!  I mean, Martin.

I’ll also take my reading at 30min into the mash - when I take a reading.  If I’m feeling extra spry I may take another at about 75min into the mash just to see what’s going on.

I check mine about 12 minutes after dough-in, and again at the end of the mash, and then often I check the kettle pH.  I use ColorpHast strips so it’s quick and easy.  I check as soon as possible so that in case I need to make an adjustment that most of the conversion hasn’t already taken place.  And I like to keep the picnic cooler mashtun lid down to maintain mash temp so normally only check once, and just crack the lid, re-checking mash temp same time.

I plug my grain bill into a calculator. In other words, I don’t physically Ck the mash for pH. I go with the calculation. Close enough. Once closed, I don’t open the mash/lauter tun until I drain it. I break up brew day into short blocks of time so that could be hours later. (I prep early -sometimes the night before, I mash in and close up the tun in the AM until I get the time to boil later in the day.)

Thanks Martin.  I was curious myself after my last kölsch where the mash PH 15min in was 5.17 and 5.3 at 60min.  I recall you/or someone else mentioning the PH will creep toward 5.4 toward end of mash…correct me if I’m wrong

I think I remember hearing Martin say that as well, to the extent that either high or low the mash ph will drive to regulate itself towards 5.4

I have been checking twice just out of my own curiosity and just like the other night I had a mash ph at 10 mins or so that was around 5.3, half way through the mash it was still there. I do not do a lot of water adjustments other than using lactic acid, I wonder if it takes longer for the mash to change/stabilize when there are added salts or adjustments being made with the mash.

Interesting.  Using ColorpHast strips I don’t always check pH at the end of the mash but always 12 - 15 minutes into the mash.  When I do check pH at the end of the mash usually it’s very close to the same reading I got the first time I checked it.

Martin, do you acidify your sparge water?