Adjust mash pH after mashing in or before?

I usually adjust the pH of my strike water before mashing in. One day while clicking through the forum I noticed someone mention the grist will affect the mash pH. I checked the next brew and noticed this seemed to be the case.

The last batch I made I used some lactic acid and ended up around 4.5 for the strike water but after mash in, pH was 5.5.

Seems like the way to go here is leave the pH alone and only adjust the mash pH. When’s the best time to do that? Right after mash in or a little after?

Many use a predictive model to recommend adjustments at mash in, then check the results at some point along the way (~15-20 minutes) making a note and applying a correction next brewday.

I like to mash only the grains that require it using RO water and adding at least 50 ppm CaCl (usually more) so the mash finds the optimal range naturally. After the mash is complete I add specialty grains that screw with mash pH for a 30 minute hot steep. This method is so consistent I quit taking pH readings after ~10 batches because it was always in the same range.

Disclaimer: Any comment I add is simply the way I brew beer. I am not paid or sponsored by anyone. There are certainly other ways that can be equally effective which other brewers may contribute. This is what I’ve found that works for me using my equipment and processes so I offer this for your consideration. YMMV

I also use a predictive model provided by Bru’n Water and I’m typically within .2 of my target of 5.3 pH.  I use Lactic Acid for my corrections to achieve my target.  I add the acid while mashing in.  Then I test the water about 15 minutes in.

What Bama says.
Predict before mash in.
Quick check after mash in, to check whether above 5.7 or below 5.0
Measure at 20-30 min.

This is of course only for new beers or processes/ equipment.
If you brew the same beer often, just do a quick check at 30 min.

“It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.” - Sherlock Holmes (A. Conan Doyle)

Like others, I use a predictive model. I then add the recommended brewing salts to the grist and lactic acid as needed to the strike water prior to mashing in. Mash pH is what counts, not water pH, so grist and brewing salts should always be included in the pH calculation. Wait at least 10 to 15 minutes after mashing in to take a pH reading.

After hearing BrewBama’s “simplified” approach, I tried it myself.  I can get my strike water to a pH of 5.5 and once my brewing salts and grains are added in the mash it falls right into place.  I hold things like Midnight Wheat, Carafa, etc. (which would be very small amounts) until the end of the mash so they don’t futz with pH.  I add them to the MT and then run off.  Color and flavor are there as usual.  I used to “get close” and then check the pH of the mash and try to adjust it on-the-fly but I really did not care for that method.  The beers have been coming out very good and I had been having some occasional haze issues and that has improved as well.

Using my house well water, I also use brewing software (Brewer’s Friend) to predict my mash pH.  All salts and (sometimes) acid go in the strike water before mash in.  I add all grains to the mash (especially the darker malts) because this helps with my pH control and is the simple method for me.

With using RO water and Brewer’s Friend or Brunwater to predict, I find that the predictive pH model is pretty spot on, so I gave up measuring pH.  I am the odd one here, as I adjust with acidulated malt, typically.  I mainly make lighter colored lagers, so my pH is pretty much in line every time, unless I am varying intentionally on the odd batch.

RO water, add calculated salts to mash water while it is heating, add grains which will have acidulated malt in most  of my grist bills. I use BeerSmith, always on target. I always test for pH whether it is a proven recipe or a new one.

I add pH adjustments to the mash water prior to adding grains. I check the pH 30-45 minutes into the mash because Martin Brungard said that it can continue to change for that length of time. Of course conversion may be complete before that and the pH during conversion is what is most important, but I think I get more repeatable and reliable numbers by waiting a bit longer.

Same here. I’m very much a “set it and forget it” type brewer. All salts, acid, and BTB go into my strike water the night before brew day. Acid amount is based on Brewer’s Friend water calculator. All my grist gets added at mash in.

Ditto except Bru’nwater

Brewing can be “geeky” and some people love all of the tools, measurements, record-keeping, etc.  After having my water analyzed by Ward Labs many times and seeing that it’s always very consistent (and then comparing notes with other brewers in my area… all using Lake Michigan water), I am able to use a more simplified approach which is what I prefer.  I do have a pH meter but once I started with this approach and knew how much lactic acid to use prior to heating the strike water I am no longer using the meter on every batch.  My bicarbonate is high so I am always looking to lower my pH (source pH is 7.9).  If you have water that may fluctuate then you have to be more careful and RO water is NOT distilled water.  I know many brewers consider it close enough to distilled but I mentioned once getting RO water in bulk from the grocery store near me and I sent a sample of that water to Ward and it had high levels of TDS and there was still considerable bicarbonate in it as well.  The machine was probably not maintained well.  Looking at our brewing water is as mysterious as looking at our harvested yeast slurry… you can’t tell what’s going on in there.  :wink:

I do the same process as Ward Labs tests from my water from western Kentucky wells have been very similar. I have used Bru’n water spreadsheet and it’s great. I had the same issue from grocery stores with high TDS levels so I would never trust it. These RO waters had a higher TDS than our tap water.

Sometimes I use new malts, and get a surprise. Then I kick myself say “should have done a minimash!”

Thanks all. Sounds like grist certainly does mess with pH so I’ll change things up to futz with pH after mash has soaked for a bit.

A general ROT is that the darker the grain, the more it will drop pH.

Yup!  I have been having a higher pH issue in my lighter beers with the base malt I have been using from a local malster.  It is higher than what Martin’s program predicts and I usually have to add some acid malt to the grain bill to bring the pH in the desired range for the beer, specifically my Amarillo IPA.  I calibrate my pH meter once a month to remove that variable from the equation and usually get a couple years out of a probe before I have to replace it.  I used to hit Martin’s predictions right on the head when I was using a different base malt some years back so I suspect the difference is the local base malt.  The local malster is going out of the malting business so I will be switching to another type of base malt, probably Rahr when I finish this bag.  I will see if that makes a difference.

Additionally, I treat my mash liquor (R.O. water) with the necessary minerals before doughing in and only adjust the sparge liquor with Phosphoric Acid to bring the pH in the same range as the mash pH.

Thanks! Appreciate the heads-up.

Quite a few here have mentioned acidulated malt for adjusting pH. I’ve used phosphoric and lactic acid but that’s it. I like not having to keep track of another adjunct. Is is worth that hassle though?

Not for me.  I find adding lactic easy and freliable.  I don’t find the acidulated adds anything that acid doesn’t.