Mash pH experiment for German Pilsner

I measured my mash pH last night in anticipation of an upcoming brewday of a German pilsner. I tested the mash pH of Weyermann pilsner malt in a solution of 50% filtered tap water and 50% RO water. My tap water averages from the yearly water report are as follows:

Alkalinity: 60ppm
Calcium: 73ppm
Magnesium: 60ppm
Sodium: 52ppm
Chloride: 55ppm
Sulfate: 124ppm
pH:9.6!!!!

(I’m also going to add 1.25 grams of CaCL2 to the mash on brewday to get my CL:SO4 ratio in line with the pilsner style and boost the Ca lost in dilution with RO water, but I didn’t add it last night.)

I plugged these numbers into the EZ Water Calculator 2.0 and they predicted a mash pH of 5.55 without any acid malt treatment. I have a Milwaukee SM101 pH meter that I calibrated before taking my measurements. I did a thin mash, 2.0 qts. per pound of grist, and the pH meter read 5.80 at 70F. Now I know that room temperature readings will be higher than the pH at mash temperature, which was around 148F, and according to Kaiser in his Overview of pH, “pH at mash temperatures (65 C/150 F) is about 0.35 pH units lower than at room temperature.” Assuming this, my pH at mash temperature was around 5.45, although in Kaiser’s own experiments show the difference was somewhere around .2 pH. So my mash pH is somewhere in the neighborhood of 5.45-5.6, and could in fact be the 5.55 predicted by the calculator. I was doing all these calculations so that I could predict the correct percentage of acidulated malt to add, which in my estimation would be 3% to get down to around in the 5.2-5.4 range.
Does this sound reasonable to those experienced in water treatment? If I’m using acidulated malt, am I correct in assuming there’s no need to treat my sparge water?

pH values quoted in literature are almost always referring to reference temperature pH (though they rarely say one way or the other). If someone says a good pH for pilsner is 5.4, they mean at reference temperature. So ultimately you don't need to worry about what the pH is at mash temperature and the only way to know for sure is to measure it at mash temperature (not good for the probe though).

More specifically the calculator is modeling reference temperature mash pH and therefore is wrong, which should not be surprising as it is an overly simple model (it is Kai's model and he as acknowledged that it is insufficient on the AHA forum recently - it is worth nothing that it is better than Palmer's model).

The problem of modeling mash pH well is likely intractable so since you own a pH meter you can forget about the models and adjust the pH after dough-in. If you consistently use the same few base malts over time you will develop a feel and will be able to get close to your desired mash pH with back of the envelope calculations.

I am confused as well as to what temperature the pH readings were taken at when people refer to their optimal mash pH range -- they just don't specify. I will stay within the range that AJ DeLange recommends of 5.4-5.7 because I know for certain he was referring to a room temperature reading. I know it is a process of trial and error when deciding which pH works best for which beers, but I would like to start from a "tasty" baseline and not suffer through a batch of insipid beer.

The OP just got too confusing with the back and forth between mash temp pH and room temp. pH. Just forget mash temp pH, as Remilade suggests. Work with room temp pH since that is the easiest on your meter. And I agree with phil, 5.4-5.7 is a good point to shoot for.

Sometimes the spreadsheets are right on for me, sometimes not. I think different malts have different effects beyond color or roast. The more 2-row base malt, the better the spreadsheets are in my experience.

philbert119 said:

I measured my mash pH last night in anticipation of an upcoming brewday of a German pilsner. I tested the mash pH of Weyermann pilsner malt in a solution of 50% filtered tap water and 50% RO water. My tap water averages from the yearly water report are as follows:

Alkalinity: 60ppm
Calcium: 73ppm
Magnesium: 60ppm
Sodium: 52ppm
Chloride: 55ppm
Sulfate: 124ppm
pH:9.6!!!!

Click to expand...

While your pH is well above the WHO recommended pH for drinking water the alkalinity is nevertheless low and it is the alkalinity that really determines what will happen. With the alkalinity this low and the given calcium and magnesium hardnesses (I conclude the numbers given are hardnesses because the profile balances reasonably well under that assumption but doesn't come close to balance if I interpret them as mg/L) the RA is only 31 and you should expect, based on this, roughly 0.05 pH shift relative to a distilled water mash which, with the Weyermann Pils malts is usually 5.75. So I'd expect a mash pH of about 5.8.

philbert119 said:

(I’m also going to add 1.25 grams of CaCL2 to the mash on brewday to get my CL:SO4 ratio in line with the pilsner style and boost the Ca lost in dilution with RO water, but I didn’t add it last night.)

I plugged these numbers into the EZ Water Calculator 2.0 and they predicted a mash pH of 5.55 without any acid malt treatment. I have a Milwaukee SM101 pH meter that I calibrated before taking my measurements. I did a thin mash, 2.0 qts. per pound of grist, and the pH meter read 5.80 at 70F.

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I just love it when the model and the actuality agree!

philbert119 said:

Now I know that room temperature readings will be higher than the pH at mash temperature, which was around 148F, and according to Kaiser in his Overview of pH, “pH at mash temperatures (65 C/150 F) is about 0.35 pH units lower than at room temperature.” Assuming this, my pH at mash temperature was around 5.45, although in Kaiser’s own experiments show the difference was somewhere around .2 pH. So my mash pH is somewhere in the neighborhood of 5.45-5.6, and could in fact be the 5.55 predicted by the calculator.

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While it is true that there is a drop I find it to be less than often advertised. I took a set of readings last time I brewed and with the Weyermann Pilsner malt in very soft water I found the slope to be between 0.0051 ad 0.0057 pH/°C. Calling room temperature 21 °C (at least that's what they always set the thermostats for in overseas hotels) and mash temperature 65 °C (a rise of 34 °C you might expect a drop of from 0.12 to 0.20 (assuming my numbers are any better than other peoples').

In any case you want mash pH to be around 5.4 to 5.5 (IMO) at room temperature. Your measured 5.8 is quite a bit above that.

philbert119 said:

I was doing all these calculations so that I could predict the correct percentage of acidulated malt to add, which in my estimation would be 3% to get down to around in the 5.2-5.4 range.
Does this sound reasonable to those experienced in water treatment?

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I'd try 3% sauermalz assuming that this would get you close to 5.5 at room temperature.

philbert119 said:

If I’m using acidulated malt, am I correct in assuming there’s no need to treat my sparge water?

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I wouldn't but as you have a meter you might want to check what runoff pH looks like when the runoff gets down to 4°P or so.

Why 2 quarts of water per pound of grain? Wouldn't that cause a higher pH? If the mash was, say 1.25 qt/#, wouldn't the pH be lower?

I'm trying to figure out if there was a reason for a thinner mash than I typically do with my pilsners.

Yooper said:

Why 2 quarts of water per pound of grain? Wouldn't that cause a higher pH? If the mash was, say 1.25 qt/#, wouldn't the pH be lower?

I'm trying to figure out if there was a reason for a thinner mash than I typically do with my pilsners.

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2 qt per pound is close to what German brewers would use, not sure if that was the reason.

As for the pH, yeah it would be lower if it was thicker, but not by much. Most of the buffering power is in the grain.

I was going for a thinner mash per the German style, but I was forced to add a little more water than I anticipated due to a stubbornly low mash temperature in my MLT. Thanks for the assistance on this experiment. I feel a much more confident about the acidulated malt additions in my mashes but will keep tweaking with my meter.