Why was my Porter mash pH 4.99...does it matter?

[CascadesBrewer]

The last few months I have put a significant amount of effort into the topic of Water Chemistry and mash pH. I picked up a $40 pH meter and have have added some minerals to a few batches, took some pH readings, and added acidified malt to some pale beers. I got a Ward Labs report and realized some of my mineral additions were not ideal so adjusted.

From my water report:

• pH 7.4
• Total Dissolved Solids (TDS) Est, ppm: 277
• Sodium, Na: 49
• Potassium, K: 3
• Calcium, Ca: 28
• Magnesium, Mg: 7
• Total Hardness, CaCO3: 99
• Sulfate, SO4-S: 6 (so 18 SO4)
• Chloride, Cl: 77
• Carbonate, CO3: < 1.0
• Bicarbonate, HCO3: 77
• Total Alkalinity, CaCO3: 63

Last weekend I brewed a 5 gal batch of Porter and measured a mash pH of 4.99 (that was taken 20 mins in and cooled to 75F, pH was 4.77 after boil). I feel like I have gotten consistent and reasonable enough readings from my meter to think it is not too far off. Brun Water predicted 5.36, and BeerSmith3 Mobile predicted 5.34.

My recipe was:

• 7.5 lbs (70%) Maris Otter Pale Malt
• 1.5 lb (14%) Brown Malt
• 1 lb (9%) Crystal 60
• 12 oz (7%) Chocolate Malt
• (Full volume mash BIAB with 7.6 gals of mash water)

My water adjustments were pretty modest (added to my mash water...goal was to hit the "Med Ale / Dark / Mod to High" profile from "Water: A Comprehensive Guide for Brewers"):

• 1.5 g Calcium Chloride
• 1.5 g Gypsum (Calcium Sulfate)
• 3.8 g Epsom Salt (Magnesium Sulfate)

I guess I am confused. Should I not add any Calcium? Should I try to raise my pH? Is my measured pH wrong? Why is it off from the predicted pH numbers? Should I just not worry about mash pH?

 

[Vale71]

You have a lot of dark malts which are very acidic. Your water calculator presumably based the prediction on average values for all malts added to the grist, if the malt you were actually using had different values then the prediction could well be off by a couple of points. Or maybe your PH meter was in error. How did you calibrate it?

If you want to start reducing your water additions I'd start with the magnesium sulfate. Magnesium tastes awful and no modern brewery would even think of adding it to their water.

 

[Big Monk]

I have a few thoughts that may help:

From my water report:

• pH 7.4
• Total Dissolved Solids (TDS) Est, ppm: 277
• Sodium, Na: 49
• Potassium, K: 3
• Calcium, Ca: 28
• Magnesium, Mg: 7
• Total Hardness, CaCO3: 99
• Sulfate, SO4-S: 6 (so 18 SO4)
• Chloride, Cl: 77
• Carbonate, CO3: < 1.0
• Bicarbonate, HCO3: 77
• Total Alkalinity, CaCO3: 63

This is a small comment but still valid: Do you have values for Nitrate, Nitrite, and Fluoride from your report? My spreadsheet shows the Cation/Anion balance is off slightly. In my following comments, I used the assumption of 81.25 ppm Alkalinity as CaCO3 because it balances your water. The difference is subtle but I wanted to make you aware of what I did.

My recipe was:

• 7.5 lbs (70%) Maris Otter Pale Malt
• 1.5 lb (14%) Brown Malt
• 1 lb (9%) Crystal 60
• 12 oz (7%) Chocolate Malt
• (Full volume mash BIAB with 7.6 gals of mash water)

• 1.5 g Calcium Chloride
• 1.5 g Gypsum (Calcium Sulfate)
• 3.8 g Epsom Salt (Magnesium Sulfate)

I ran your numbers through my own spreadsheet (take with a grain of salt). Your Grist pH (no salts or additional acids) came to 5.55. Adding in the minerals you used brings the estimated Mash pH to 5.49. Did you use any other acids?

Last weekend I brewed a 5 gal batch of Porter and measured a mash pH of 4.99 (that was taken 20 mins in and cooled to 75F, pH was 4.77 after boil). I feel like I have gotten consistent and reasonable enough readings from my meter to think it is not too far off. Brun Water predicted 5.36, and BeerSmith3 Mobile predicted 5.34.

I mean no offense to you but I have to at least point out that user error may be at play here either in the use of Brun Water or the measurements. I just can't see this grain bill driving pH that low.

I guess I am confused. Should I not add any Calcium? Should I try to raise my pH? Is my measured pH wrong? Why is it off from the predicted pH numbers? Should I just not worry about mash pH?

I would keep the Calcium as it's really only a modest addition. What values for color did you enter for each grain? Did you select the proper grain type for the brown malt?

If you want to start reducing your water additions I'd start with the magnesium sulfate. Magnesium tastes awful and no modern brewery would even think of adding it to their water.

I agree with @Vale71 on this point. I rarely bother with MgSO4 unless I want some additional Sulfate without Calcium. Magnesium has it's place in trace amounts from a fermentation standpoint but those amounts are way below what you already have in your water.


All you can do at this point is wait and taste how the beer turns out. Keep an eye on how it attenuates, trackbue final gravity and taste the beer.

 

[Big Monk]

You have a lot of dark malts which are very acidic. Your water calculator presumably based the prediction on average values for all malts added to the grist, if the malt you were actually using had different values then the prediction could well be off by a couple of points.

The only reason I would counter this is due to the fact that I don’t think Brun Water takes into account the color of roasted malts into the equation. So there are no user inputs to determine roasted malt acidity except grain weights.

With that said, I ran some analysis with all the non-MO malts selected as a form of dark roasted malt in my sheet and it still didn’t drive the estimated pH as low as the measurements seen.

 

[CascadesBrewer]

Thanks for the feedback.

This is a small comment but still valid: Do you have values for Nitrate, Nitrite, and Fluoride from your report? My spreadsheet shows the Cation/Anion balance is off slightly. In my following comments, I used the assumption of 81.25 ppm Alkalinity as CaCO3 because it balances your water. The difference is subtle but I wanted to make you aware of what I did.

The values were copied from my Ward Lab's report. I don't have Nitrate, Nitrite, and Fluoride values. I did not include the following in my first post:

• Electrical Conductivity, mmho/cm 0.46
• Cations / Anions, me/L 4.2 / 3.9
• Total Phosphorus, P 0.46
• Total Iron, Fe < 0.01

Did you use any other acids?

No. No acid malt or acid.

I mean no offense to you but I have to at least point out that user error may be at play here either in the use of Brun Water or the measurements. I just can't see this grain bill driving pH that low.

I think I measured my additions well, and I know it was small amounts (so I am pretty sure I did not add 10x the planned amounts). I can look closer at my pH meter and calibration process.

What values for color did you enter for each grain? Did you select the proper grain type for the brown malt?

I have 2-Row 3L, Brown Malt 45L, Crystal 60L and Chocolate Malt 350L. Hmmm...for the Brown Malt if I select "Roast Malt" in Brun Water, it warns me that the color is too low but that drops the predicted pH from 5.36 to 5.19. So I guess I don't know if Brown Malt is a Base Malt or a Roast Malt. Selecting Crystal Malt gives a pH of 5.38.

I agree with @Vale71 on this point. I rarely bother with MgSO4 unless I want some additional Sulfate without Calcium. Magnesium has it's place in trace amounts from a fermentation standpoint but those amounts are way below what you already have in your water.

Yeah...that is something I am still trying to figure out. At least on paper, MgSO4 seems to make it easier for me to even out my Sulfate to Chloride ratio without getting my Calcium too high.

 

[Silver_Is_Money]

Mash Made Easy version 5.90 is coming in at an initial prediction of 5.28 as the mash pH. This is for a presumed 4 gallons of mash water (Water to grist ratio = ~1.50), and the presumption that your 63 ppm alkalinity is correct. If the mash water is less than this, the mash pH prediction falls slightly due to higher mineralization ppm's.

If I raise the alkalinity until full cation/anion balance is achieved, the predicted mash pH jumps to 5.31.

 

[CascadesBrewer]

How did you calibrate it?

My meter is this one: https://smile.amazon.com/gp/product/B00ST3VTQ4. I am following the 3 steps in the manual using solution mixed from packets (starting with 9, then 7 then 4). The calibration solution is stored in small jars but is about 6 weeks old. I will mix up some new calibration solution and compare them.

 

[CascadesBrewer]

Mash Made Easy version 5.90 is coming in at an initial prediction of 5.28 as the mash pH. This is for a presumed 4 gallons of mash water (Water to grist ratio = ~1.50), and the presumption that your 63 ppm alkalinity is correct. If the mash water is less than this, the mash pH prediction falls slightly due to higher mineralization ppm's.

If it matters, this was a full volume mash, so all the grains were mashed in ~7.6 gals of treated water.

 

[Silver_Is_Money]

If it matters, this was a full volume mash, so all the grains were mashed in ~7.6 gals of treated water.

This change brings MME to 5.33 as its 'default' mash pH prediction (for the case of the base malt selector cell set to Maris Otter).

 

[Silver_Is_Money]

Simpson's "Brown Malt" is about 190L on average, and can range from 162L to 226L per their specs.

By comparison, 45L seems quite low for a "Brown Malt".

EDIT: But then I also see Crisp Brown Malt at ~65L (with a range of 60-70L).

 

[Silver_Is_Money]

I just checked D.M. Riffe's rather limited data on Brown Malts (two examples, one 55L and the other 65L), and they seem to generally fall more in line with Biscuit, Victory and Melanoidin as to the span of their range of acidity. They are clearly not in the roasted malt class in this regard.

55L (DI pH = 5.19)
65L (DI pH = 4.97)

 

[Big Monk]

Simpson's "Brown Malt" is about 190L on average, and can range from 162L to 226L per their specs.

By comparison, 45L seems quite low for a "Brown Malt".

EDIT: But then I also see Crisp Brown Malt at ~65L (with a range of 60-70L).

I would imagine that selecting "Crystal Malt" would better capture this malt rather than roasted.

 

[CascadesBrewer]

EDIT: But then I also see Crisp Brown Malt at ~65L (with a range of 60-70L).

Yeah, this is Crisp and the package says 65 L.

I mixed up a fresh batch of calibration solutions, and the solutions from 6 weeks ago pretty much measures dead on to the new solution.

I suspect I need to pay more attention to my calibration process (ensure I am leaving the meter in long enough, pay closer attention to the reading values, etc.). When this reading seemed odd, I should have checked my meter against my 4.0 solution. Though, I would be surprised if my meter was off more than 0.1. When I pulled it out of the closet and tried it with the new 4.0 solution it read 3.91 (at 68.1 F).

 

[cire]

pH 4.99 in a brew with 30% crystal and roasted malts and 63 mg/L alkalinity does not surprise me. While I brew stouts with just a little more alkalinity but substantially more calcium, it would be rare to include more than 10% dark grains. This is primarily due to the belief there may be insufficient enzymes supplied by the base malt to fully convert all the roasted grains to fermentable, although your recipe includes crystal malt that I don't.

However, back to the point, that recipe includes a significant mass of roasted grains which have yet to be proven consistent from maltster to maltster and batch to batch. My Baird's brown malt was found to have a DI pH of 4.52 and wonder if that was used to predict your mash pH it would be nearer your measurement.

 

[Big Monk]

pH 4.99 in a brew with 30% crystal and roasted malts and 63 mg/L alkalinity does not surprise me. While I brew stouts with just a little more alkalinity but substantially more calcium, it would be rare to include more than 10% dark grains. This is primarily due to the belief there may be insufficient enzymes supplied by the base malt to fully convert all the roasted grains to fermentable, although your recipe includes crystal malt that I don't.

However, back to the point, that recipe includes a significant mass of roasted grains which have yet to be proven consistent from maltster to maltster and batch to batch. My Baird's brown malt was found to have a DI pH of 4.52 and wonder if that was used to predict your mash pH it would be nearer your measurement.

I can try that number tomorrow. I still doubt it would drag his estimated pH down to 4.99 though.

 

[Druman07]

Not much you can do at this point, keep notes so you know to adjust PH for the next time around. I find the difference between my calculator and actual can be up to .2, with the calculator always being on the high side.

 

[Silver_Is_Money]

My Baird's brown malt was found to have a DI pH of 4.52 and wonder if that was used to predict your mash pH it would be nearer your measurement.

Using the DI pH manual override feature, and going with 4.52 as the DI pH for the brown malt thereby, Mash Made Easy predicts a mash pH of 5.10.

The MME internally assigned DI pH for 65L Brown is 4.97.

 

[cire]

Using the DI pH manual override feature, and going with 4.52 as the DI pH for the brown malt thereby, Mash Made Easy predicts a mash pH of 5.10.

The MME internally assigned DI pH for 65L Brown is 4.97.

Well that would suggest that if both brown malts were of similar acidity, a mash pH of 4.99 should not not altogether unexpected. Some time ago i MADE a stout with a low mash pH and the beer was excellent, so I'd not be worried about this beer if it were mine. One problem very low mash pH is low fermentability, but the one knew of was something like pH 4.6.

 

[CascadesBrewer]

Well that would suggest that if both brown malts were of similar acidity, a mash pH of 4.99 should not not altogether unexpected. Some time ago i MADE a stout with a low mash pH and the beer was excellent, so I'd not be worried about this beer if it were mine. One problem very low mash pH is low fermentability, but the one knew of was something like pH 4.6.

Interesting. I have brewed all-grain for many years without knowing anything about pH, so I suspect this one will turn out fine as well. Unfortunately, as I got to boil I noticed my brewing thermometer was off several degrees, so there is a decent chance my 152F mash was in the upper 150s...so my FG might be high anyway. I hit my target fermenter volume and OG (1.052 vs target 1.053 and 73% efficiency) and the beer is chugging away in the fermenter now.

 

[Vale71]

Sounds like your calibration procedure is impeccable and your measurements can be trusted. One other variable to consider is that your water report is, if it's coming from your utilities provider, probably an average over several measurements possibly covering a timespan as large as a whole year. Depending on where the water is coming from there can be very strong seasonal variation, so there is a good chance your actual brewing water had, on that day, a much lower residual alkalinity than what you based your calculations on all of which would contribute to the lower than expected actual PH values.

 

[CascadesBrewer]

Sounds like your calibration procedure is impeccable and your measurements can be trusted.

Maybe...I am still learning and figured learning with a inexpensive pH meter would be better than throwing money at an expensive one.

One other variable to consider is that your water report is, if it's coming from your utilities provider, probably an average over several measurements possibly covering a timespan as large as a whole year.

It was a report from Ward Lab's that I just got back about a month ago. I am curious how reliable/unreliable that is from month to month and year to year. I had a report from a friend that was several years old but from the same water provider and some numbers shifted quite a bit (mostly my Sodium and Chloride levels are about 3x his report). Somewhere on my todo list is to contact my water provider and see if they have a more detailed report than they post online.

 

[Vale71]

Just to give you an idea how variable your water composition could be, the TDS meter on the inlet of my RO system can read 280 ppm on one day and then 140 ppm the very next day (usually after heavy rains). Any in-depth analysis that's perfomed on a sample taken when the TDS was at 280 ppm will be quite useless if you draw your water on a day when it reads only half of that.

 

[Druman07]

Maybe...I am still learning and figured learning with a inexpensive pH meter would be better than throwing money at an expensive one.

I follow the same mantra also, and calibrate everytime I brew. I was looking at the Thermworks PH meter which is tempting due to its reasonable price, but my current method is working for me so I can't really justify the expense at this time. Measurement is ball park because my meter only goes to 0.1.