Pejepscot
Member
Hi Folks,
I performed this quick study to reassure myself and others who might be in the same situation using Star San.
I found that when I mixed up Star San at the rate of 0.5 oz per 2.5 gallons in my tap water it became cloudy instantly. Normally cloudiness indicates that your Star San is no longer effective (ie, the pH has risen above 3.0) so I took some to my lab today and tested it out...
Here you can see the Star San mixed at the above rate (6.0 mL per gallon of tap water) after just one minute. (Look in the BIG beaker that the pH meter's electrode is dangling in) It is already quite cloudy, but the pH is at 2.46 using a Mettler-Toledo pH meter with two point standardization at pH4.0 and 7.0.
This is a close-up showing the cloudiness after 10 minutes - it's REALLY cloudy, but the pH is still below 3.0 at 2.45 - hooray!.
Here you can see the Star San mixed in tap water next to a batch of Star San mixed at the same rate in our lab grade deionized R/O water . This water has been deionized to the level of 18.25 megohms per centimeter - high purity water. The deionized water+ Star San is essentially perfectly clear and colorless and remained that way with a pH of about 2.25.
Here is some of the test data:
1 gallon tap water+6.0mL Star San (Tap water pH = 6.88)
Time (min) pH observation
0 2.46 cloudiness apparent immediately
3 2.43 increased cloudiness
5 2.45 very cloudy
10 2.45 "
15 2.46 "
30 2.44 "
90 2.41 "
120 2.41 "
1 gallon DI/RO water+6.0mL Star San (DI/RO water pH = 5.54)
Time (min) pH observation
0 2.28 clear and colorless
3 2.28 "
5 2.26 "
10 2.25 "
15 2.25 "
30 2.25 "
60 2.24 "
My tap water clearly has some component that is reacting with the surfactant in Star San and causing immediate cloudiness, but not affecting the pH.
Here are my tap water test results (with max allowable concentration in parenthesis)
pH 6.6 (6.5-8.5) SU
Chloride 53 (250) mg/L
total hardness 114 (*)
calcium 33 (no max listed) mg/L
copper 0.045 (1.3) mg/L
iron 0.058 (0.3) mg/L
magnesium 7.4 (no max listed) mg/L
manganese 0.043 (0.050) mg/L
uranium 4.1 (30) ug/L
(*less than 150 considered softer than ideal)
It seems to me that the calcium and magnesium must be the culprits.
CONCLUSION:
It seems that if your Star San gets cloudy very quickly when diluted in tap water, this DOES NOT INDICATE THAT THE STARSAN HAS LOST ITS SANITIZING ABILITY. I plan to make my StarSan fresh each day that I need it and I feel secure that it will stay below pH3.0 for the entire day and be an effective sanitizer.
RDWHAHB!
I performed this quick study to reassure myself and others who might be in the same situation using Star San.
I found that when I mixed up Star San at the rate of 0.5 oz per 2.5 gallons in my tap water it became cloudy instantly. Normally cloudiness indicates that your Star San is no longer effective (ie, the pH has risen above 3.0) so I took some to my lab today and tested it out...
Here you can see the Star San mixed at the above rate (6.0 mL per gallon of tap water) after just one minute. (Look in the BIG beaker that the pH meter's electrode is dangling in) It is already quite cloudy, but the pH is at 2.46 using a Mettler-Toledo pH meter with two point standardization at pH4.0 and 7.0.
This is a close-up showing the cloudiness after 10 minutes - it's REALLY cloudy, but the pH is still below 3.0 at 2.45 - hooray!.
Here you can see the Star San mixed in tap water next to a batch of Star San mixed at the same rate in our lab grade deionized R/O water . This water has been deionized to the level of 18.25 megohms per centimeter - high purity water. The deionized water+ Star San is essentially perfectly clear and colorless and remained that way with a pH of about 2.25.
Here is some of the test data:
1 gallon tap water+6.0mL Star San (Tap water pH = 6.88)
Time (min) pH observation
0 2.46 cloudiness apparent immediately
3 2.43 increased cloudiness
5 2.45 very cloudy
10 2.45 "
15 2.46 "
30 2.44 "
90 2.41 "
120 2.41 "
1 gallon DI/RO water+6.0mL Star San (DI/RO water pH = 5.54)
Time (min) pH observation
0 2.28 clear and colorless
3 2.28 "
5 2.26 "
10 2.25 "
15 2.25 "
30 2.25 "
60 2.24 "
My tap water clearly has some component that is reacting with the surfactant in Star San and causing immediate cloudiness, but not affecting the pH.
Here are my tap water test results (with max allowable concentration in parenthesis)
pH 6.6 (6.5-8.5) SU
Chloride 53 (250) mg/L
total hardness 114 (*)
calcium 33 (no max listed) mg/L
copper 0.045 (1.3) mg/L
iron 0.058 (0.3) mg/L
magnesium 7.4 (no max listed) mg/L
manganese 0.043 (0.050) mg/L
uranium 4.1 (30) ug/L
(*less than 150 considered softer than ideal)
It seems to me that the calcium and magnesium must be the culprits.
CONCLUSION:
It seems that if your Star San gets cloudy very quickly when diluted in tap water, this DOES NOT INDICATE THAT THE STARSAN HAS LOST ITS SANITIZING ABILITY. I plan to make my StarSan fresh each day that I need it and I feel secure that it will stay below pH3.0 for the entire day and be an effective sanitizer.
RDWHAHB!