Measuring and adjusting the pH of my sparge water continues to be the single most painful part of my brew day. I am hoping someone can point out what I?m doing wrong. Oddly, measuring and adjusting mash pH has not been a problem. I must be the only person on the planet having this problem, so I am hoping the fix is easy. Here is my setup and routine:
Equipment: Electric Brewery controller with three 30-gallon Blichmann tanks
pH Meter: Milwaukee MW 102 with separate, replaceable temp and pH probes
The pH probe is less than 1 year old and has been used for 8 brew sessions. Calibrating and storage solutions are fresh. The meter itself is about 2 years old and has been handled very gently. The temp probe has never been replaced.
Two days before brewing I calibrate the meter using new Milwaukee calibration solution, using one packet each of 7.01 and 4.01 solution. I always store the pH probe in Milwaukee MA9015 storage solution. Manufacturer procedures are followed exactly. Calibrating and storage solutions are less than 1 year old.
On brew day when it is time to measure my sparge water pH, usually during the mash-out, I take the probe from the storage solution for use. I prepare a small ice bath and use a shot glass to take small sample, about 1/2 ounce, enough to sufficiently submerge the pH probe. The sample is chilled until the temp probe shows 20?C/68?F and the shot glass is removed from the ice bath. I then put the pH probe into the sample, keeping the temp probe in it too and wait until the unit locks in (flashing hour glass goes away). That?s it. Now for the odd part. My readings may be all over the place. For example:
Initial reading of untreated water: 6.10
Add 10 drops of lactic acid; wait 3 minutes while sparge water is recirculated from tank spigot back over top of tank. Resulting in pH of 6.31. How is it possible for the pH to go UP after adding acid?
Add 10 drops of lactic acid; wait 3 minutes to mix in as above. Resulting in pH of 6.11. OK, not unexpected.
Add 10 drops of lactic acid; wait 3 minutes to mix in as above. Resulting in pH of 4.92??? Now I?m stumped.
The volume of sparge water I?m adjusting is 17 gallons and is at 170?F. I have had similar results with more than one pH probe and differing volumes of sparge water, so I?m thinking the problem lies in my procedure. Questions I have are:
How long should I wait after adding lactic acid when I can re-measure? My pump is the March nano-brewery which easily recirculates my sparge tank in a matter of minutes. Manually mixing doesn?t seem to make a difference. Should I agitate the pH probe while measuring the sample? I?ve tried both ways. For completeness, my target sparge water pH is 5.6 to 5.8, and the water has been treated the night before with campden to remove chlorine, completely crushed and mixed in.
Thanks for whatever guidance you can pass along.
Equipment: Electric Brewery controller with three 30-gallon Blichmann tanks
pH Meter: Milwaukee MW 102 with separate, replaceable temp and pH probes
The pH probe is less than 1 year old and has been used for 8 brew sessions. Calibrating and storage solutions are fresh. The meter itself is about 2 years old and has been handled very gently. The temp probe has never been replaced.
Two days before brewing I calibrate the meter using new Milwaukee calibration solution, using one packet each of 7.01 and 4.01 solution. I always store the pH probe in Milwaukee MA9015 storage solution. Manufacturer procedures are followed exactly. Calibrating and storage solutions are less than 1 year old.
On brew day when it is time to measure my sparge water pH, usually during the mash-out, I take the probe from the storage solution for use. I prepare a small ice bath and use a shot glass to take small sample, about 1/2 ounce, enough to sufficiently submerge the pH probe. The sample is chilled until the temp probe shows 20?C/68?F and the shot glass is removed from the ice bath. I then put the pH probe into the sample, keeping the temp probe in it too and wait until the unit locks in (flashing hour glass goes away). That?s it. Now for the odd part. My readings may be all over the place. For example:
Initial reading of untreated water: 6.10
Add 10 drops of lactic acid; wait 3 minutes while sparge water is recirculated from tank spigot back over top of tank. Resulting in pH of 6.31. How is it possible for the pH to go UP after adding acid?
Add 10 drops of lactic acid; wait 3 minutes to mix in as above. Resulting in pH of 6.11. OK, not unexpected.
Add 10 drops of lactic acid; wait 3 minutes to mix in as above. Resulting in pH of 4.92??? Now I?m stumped.
The volume of sparge water I?m adjusting is 17 gallons and is at 170?F. I have had similar results with more than one pH probe and differing volumes of sparge water, so I?m thinking the problem lies in my procedure. Questions I have are:
How long should I wait after adding lactic acid when I can re-measure? My pump is the March nano-brewery which easily recirculates my sparge tank in a matter of minutes. Manually mixing doesn?t seem to make a difference. Should I agitate the pH probe while measuring the sample? I?ve tried both ways. For completeness, my target sparge water pH is 5.6 to 5.8, and the water has been treated the night before with campden to remove chlorine, completely crushed and mixed in.
Thanks for whatever guidance you can pass along.