Star San cloudiness lab report

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Pejepscot

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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...

starsantap1min.jpg


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.


starsantapcloudiness.jpg


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!.


starsantapvsdiro.jpg


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!
 
Thanks a bunch for taking the time and effort to scientifically test your problem and post the results. This is always so much better than speculation!

If you feel so inclined to continue this test, it would be very interesting to see what the pH reading on those samples would be after they had been stored in some sort of simple plastic or glass container for a period of 4-8 weeks. I hate the thoughts of mixing up 5 gallons of this stuff so often, but I do it anyway. I bet that Star San stored in a glass jug with a lid will hold it's pH for quite a long time, depending on what it gets diluted with as it is used...

Hi Folks,

I performed this quick study to reassure myself and others who might be in the same situation using Star San.
 
The other thing we know is that for 79 cents buy a gallon of distiled water and you will know that when it gets cloudy it is time to replace it.
 
The other thing we know is that for 79 cents buy a gallon of distiled water and you will know that when it gets cloudy it is time to replace it.

I think that there will be a little more to it than that. The cloudiness is not an indicator of acidity or alkalinity. In the case of this test, the cloudiness is being caused by a reaction with something in the water that isn't affecting the pH of the solution. Mixing additional solubles into the solution could affect the pH without showing signs of cloudiness, which might render the Star San useless with no visible indications.
 
I think the cloudiness example is given as a rough estimate. Kind of like saying fermentation is over when the krausen drops. It doesn't always mean fermentation is complete. If you have the ability to test the pH, that is definitely the way to go.

I typically only mix a squirt bottle up at time (~500ml). You don't need to soak anything in star san, as long as the surface is wet (or foamy) it's working, and it doesn't need to stay wet that long.

If you can, I would also be really interested in see the same test performed (on the same samples) after a few weeks. As you mentioned, something in the tap water is reacting with the StarSan. It's fair to say that cloudy starsan at the time of mixing may be OK, but after a month....?

Thanks for the detailed write up, this is good stuff!
 
Cool, thanks for this write up! +1 on leaving the samples sealed up for a month and see how the pH changes over time.
 
Great thread. Nice touch and great demonstration. I've been meaning to do some DO 'experiments' as I have access to a YSI meter. You've inspired me to get off my a$$ and do it.
 
Nice write up.

You don't happen to have access to any LB plates and some DH5alpha e. coli do you? You could extend your test a little further by allowing the StarSan to sit out for a month, spray some on a LB plate, and streak some DH5alpha. I think that would be a fair test.

At least that's what I'd do if I were still in the lab! I got out and now I work for a company that sells your Mettler Toledo pH meter:)

Dr. Jersh
 
this makes me feel better. i had some in my kitchen for a couple weeks, and i made 2 batched of beer using it. after reading this i got scared, and i am worried the 2 batches are ruined. i made a fresh 2.5 gal of starsan last night for my brew.


i need to get some ph test strips. the starsan i made last night wwas cloudy right away.
 
You obviously know you're way around a lab so it would be easy to add salts to your milli-Q or de-ionized water at rates that approach your tap water to see exactly which salts are contributing to cloudiness. Infact, a titration of Mg or Ca would be a neat little experiment.

By the way is your water treated with chloramine or some form of -chlorite?
 
Infact, a titration of Mg or Ca would be a neat little experiment.

Runhard- That's a very good idea! I'll give it a go next chance I get.

My water is well water that has no treatment or filtration whatsoever. What I get out of the tap is what Mother nature put in the ground - and it has a beautiful taste.

In response to Jersh- No, unfortunately I don't have access to any microbiological supplies - but there IS this gal in the microbiology lab down the hall.....:) I'll bet she'll trade a little experimentation for six of homebrew!

I'll keep you posted.


Ren
 
this makes me feel better. i had some in my kitchen for a couple weeks, and i made 2 batched of beer using it. after reading this i got scared, and i am worried the 2 batches are ruined. i made a fresh 2.5 gal of starsan last night for my brew.


i need to get some ph test strips. the starsan i made last night wwas cloudy right away.

Hey JonP-

I think that these data should ease your mind rather than get you worried. What the test showed was that Star San which becomes instantly cloudy in tap water still should retain it's sanitizing power, because the pH stays below 3 for quite some time.

Regarding mixing up of a fresh batch each brewing event - I have been mixing up a gallon at a time to use for each event. Each gallon only requires 6.0mL of StarSan. My $18 bottle of Star San contains 900mL, so I can make 150 gallon sized batches of diluted Star San from this one bottle, at a cost of $0.12 per gallon. You can't even mail a letter for twelve cents!

Each batch of beer has (for me) three "brewing events" 1. brewing, 2. racking to secondary, 3. bottling. If I use a gallon of diluted Star San for each event, that means my $18 bottle of Star San will sanitize 50 batches of beer at a cost of $0.36 per batch or less than a penny a bottle -I feel like that can't be beat!

Cheers,

Ren
 
30mg/l of uranium?

wow, and i thought we were high in these parts!
holy hell.

excellent post btw, that just kinda suprised me. we test 2 times a year, and never have over .1mg/l

read wrong... thats 4.1
ok... sorry :)
 
30mg/l of uranium?

wow, and i thought we were high in these parts!
holy hell.

excellent post btw, that just kinda suprised me. we test 2 times a year, and never have over .1mg/l
The interim maximum acceptable concentration (IMAC) for uranium in drinking water is 0.02 mg/L


Sorry nosmatt, I had the wrong units listed it should be ug/l :eek:

Max allowable = 30ug/l
my water = 4.1ug/l

Phew, you had me worried there!

Ren
 
Nice write up.

You don't happen to have access to any LB plates and some DH5alpha e. coli do you? You could extend your test a little further by allowing the StarSan to sit out for a month, spray some on a LB plate, and streak some DH5alpha. I think that would be a fair test.

At least that's what I'd do if I were still in the lab! I got out and now I work for a company that sells your Mettler Toledo pH meter:)

Dr. Jersh

I use E. Coli for my research. I could do the DH5a test if need be.

Star-San into my tap water turns cloudy instantly as well. I used this mixture for a long time and didn't have anything bad happen. I was still a little uneasy though, so I bought some distilled water and used that to make up a 2 gallon batch. I have been using the same 2 gallons now for about 5 months. I am still on my first bottle of Star-San that is halfway full and I've been brewing for almost 2 years.
 
My water is well water that has no treatment or filtration whatsoever. What I get out of the tap is what Mother nature put in the ground - and it has a beautiful taste.
Ren

Where I grew up we had a well and the water was soft. It's difficult to explain to those who've never had well water but as you stated it does taste much better than every municipality that I've tried. I believe this is simply based on the salts that are present. I now live where we get our water from limestone aquifers and all that calcium carbonate is troublesome. Tap pH of 8.8-9.1 depending on time of year and Ca2+ levels always above 150 often above 200. I keep thinking that I should transport a couple 55 gallon drums of my parents well water back with me for brewing purposes although getting them out of the truck might make for some entertaing viewing for my neighbors.

I've often wanted to tiitrate Ca and Mg into RO water at work but our lab is a GLP/FDA regulated environment and I'd likely get the proverbial axe if I got caught by our quality assurance department. IF you get a chance and can see which salts are contributing to the cloudiness when combined with STar Sans let us know.

Runhard trainhard raceEZ

Jeffrey
 
Nice write up.

You don't happen to have access to any LB plates and some DH5alpha e. coli do you? You could extend your test a little further by allowing the StarSan to sit out for a month, spray some on a LB plate, and streak some DH5alpha. I think that would be a fair test.

At least that's what I'd do if I were still in the lab! I got out and now I work for a company that sells your Mettler Toledo pH meter:)

Dr. Jersh

That's a cool idea to test the efficacy but taking the pH reading is so much easier. If one chose to conduct the microbiological test then the appropriate controls would need to be included. Gosh, if the lab where I worked wasn't so highly regulated I could sure have some fun with some of the ideas people are tossing about.
 
I go the 1 gal distilled water route and mix up a batch and use till gone. That could take a month or more. Interested to see starage test with both tap & distilled with a Ph check every week till it's unusable. Woudl do it my self if I had a Ph meter but I do not.
 
I am glad to hear that the PH is not badly affected by the cloudyness but I heard Charlie talk about that is the detergent getting bound up with the hardness in the water. I would question if the star-san solution works as well as a surfactant with the cloudyness and thus be as good as non-cloudy.
 
Though not nearly as scientific as the OP's experiment, I did my own. My tap water is extremely hard (21 grains hard). I mixed a gallon of star san with tap water and a gallon with RO/DI water. Both came in at approx ph of 3 (using ph test strips so not as accurate as the OP's test). The RO/DI mixture was crystal clear and my tap water batch was cloudy white as soon as the star san hit the water. Take it for what it's worth. Also, I checked both after 1 weak and they both still were at approx 3.
 
Does using distilled water get rid of that nasty sludge that is left over at the bottom of the bucket after 2+ weeks?
 
Does using distilled water get rid of that nasty sludge that is left over at the bottom of the bucket after 2+ weeks?

Yup. All that's happening with tap water is that the minerals in it cause the surfactant in the StarSan to settle out, creating the slimy white stuff.
 
I realize this is an old thread, but it's a useful reference and I have another data point :).

I'm also finding that StarSan turns fairly cloudy as soon as I mix it with my tap water. I got hold of some pH strips today (with a resolution of 0.5) and am happy to see that the pH of a 24 hour old sample is still around 2. A freshly-made sample also gives 2 (same colours) when dipping the strip in the water after just a few seconds, while the foam on top is just a touch more acidic (1.5-2).

I also had my water tested a few weeks ago with the following results (PPM):

pH 7.8
Sodium 53
Potassium 3
Calcium 91
Magnesium 18
Total hardness 303
Nitrate 1.4
Sulphate 64
Chloride 37
Carbonate <1
Bicarbonate 191
Total alkalinity 156
Copper 0.04

... I have quite a lot of chlorine in my water as well (pretty nice for brewing otherwise!). It's not obvious to me what the culprit is, but this thread has been quite reassuring!

Cheers,

James.
 
I read a couple threads about dehumidifier water for brewing...seems most thought there's too much potential for lead or other things (dust, dander, microbes) you wouldn't want in your beer...not worth the effort with the low cost of RO at the store...but how about as a cheap source of Starsan mixer? Maybe run it through a coffee filter? No need to boil, the Starsan should kill everything, right? I know SWMBO uses it in her iron (if I "harvest" it for her) and I use it to add to the car battery too. As usual...just thinkin' "cheap"...with a small dose of "eco" (already used/paid for the electricity, right?).
 
OK...couldn't stand the suspense. My bottle says add 1 oz. starsan to 5 gallons or 1:640 ratio. So I went to my dehumidifier and grabbed 2 cups. 2 cups (1 pint) is 1/40th of 5 gallons. So I need 1/40 of a fluid ounce. With 6 tsp per fluid ounce (had to look that one up) I figure 1/4 tsp is 1/24th of an ounce...or a fairly strong Starsan solution. Result is 2 cups of crystal clear starsan solution. As long as I don't leave 2 cups in my carboy (not that I've ever done that more than once!) only trace amounts of bad metals could possibly be introduced...probably more risk in my well water through 25 year old copper plumbing. Thoughts???
 
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