pH Throughout the Brew

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Senior Monkey

Mar 4, 2019
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We’ve been brewing for 3 years now and have learned so much from this website and from John Palmer’s books. My questions concern pH readings throughout the brewing process.

Here are the pH readings for our most recent brew - a West Coast IPA.
20 minutes into the 60 minute mash - 5.3
30 minutes into the mash - 5.22
40 minutes into the mash - 5.24
Sparge water - 5.56
Last running from the mash tun into the boil kettle - 5.3
Pre-boil - 5.39
Wort cooled and into the fermenters - 5.30
Beer transferred into kegs after fermentation and conditioning - 4.76
Beer after cold crashing and carbonating - 4.5

  1. During the mash and before we started sparging, the pH only decreased .06. Is this typical? Mr. Palmer says the pH tends to drop .2 during the mash.
  2. During the boil, the pH only dropped .09. Our Palmer book says it tends to drop .3 during the boil. What happened or didn’t happen during the boil?
  3. During fermentation and before cold crashing and carbonating, the pH dropped .54 to 4.76. This is close to what the Palmer book says. After carbonation, the pH was 4.5. Does carbonation or a few days aging in a keg cause the pH to drop?

I anticipate that lots of detail will be requested by people who may offer answers. So here are the details.
WATER - We add brewing salts several days ahead of time to our dechlorinated, very soft city water. After additions we have in ppm
Calcium 102
Magnesium 28
Sodium 7
Chloride 66
Sulfate 255
If I did the calculations correctly, the Residual Alkalinity is -63.
We treat both the brewing water and the sparge water. We further acidify the sparge water with phosphoric acid to bring it under 5.8.

13 lbs premium 2-row
13 lbs Northwest pale ale malt
1.5 lbs Crystal 15
.33 lbs Sauermalz

We mashed the grains in 39 quarts of treated water.
Yeast was WLP 099 San Diego Super Yeast with which we prepared starter solutions: one package of yeast for each 2 liter flask. (I just used tap water. I created about 1600 ml of starter solution and did not decant the starter. We just tossed one flask into each fermenter.)

We mashed for 60 minutes, continually recirculating liquid from the bottom of the mash tun and sprinkling it over the top. We try to keep the temperature near 148 F. When taking a pH reading, we first cooled the hot wort to room temperature.

We boiled about 13 gallons of wort for 60 minutes.
  • 2 oz Chinook pellet for 60 minutes
  • 2 oz Simcoe pellet for 20 minutes
  • 3 oz of Mosaic leaf in a hop rocket inserted into the cooling system. The temperature of the wort going through the hop rocket was 170F.

About 5.5 gallons of cooled wort - 68F - and added to each fermenter The OG was 1.060. We pitched the yeast starter. Initial fermentation was finished in 6 day when the gravity stabilized at 1.010 for several days. We then added 1 oz each of Citra leaf and Simcoe leaf to each fermenter and allowed the yeast to continue to work for 5 more days.

Finally, we transferred the beer to two corny kegs and added 1 oz of Citra cryo pellet to each keg for a second dry hopping. After 4 days, we removed the hops ,measured the FG (1.010), cold-crashed and began carbonating.

The beer tastes great.

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