I made up and small batch of starsan jkust to sanatize my secondary and my auto siphon. i know that it is inexpensive stuff but on my budget its like gold. so could i save it and reuse it? how long does it last? whats a good sign thats its time to make a new batch?
If you made it with tap water it will last way less than using distilled water. It’s really a PH thing; I have a squirt bottle that lasts at least a month; I’ll put fresh stuff in the squeeze bottle every batch of beer. If you can test the PH you would know for sure, but I think it starts to turn cloudy when it fades. Kaiser will be along shortly with his doctoral thesis on Starsan. 
It can last for a good while. I keep a spray bottle of it around as well. I also at one point kept a gallon jug of it around I was reusing for awhile and I kept testing it with cheapo pH strips. Even after it turned cloudy the pH didn’t appear to drop for the length of time I was using it for. Keep it in a closed container away from sunlight and you should be fine for two weeks.
I keep mine in a corny and have no problem keepin it. pH 1.8 after a month on this batch so far,
What IS Star San? (I have it and I use it, but what are its ingredients?)
I have noticed that a white residue/film tend to collect on the bottom of the vessel if the prepared Star San solution is stored for awhile (regardless of whether or not the solution itself remains clear or cloudy).
I also presume that if one only puts clean items (like spoons, hoses, glassware, etc) in contact with the star san solution, then it will last longer. If you’re not cleaning your stuff before dunking it, or are immersing your hands and arms in the solution, then more chemical reactions are probably taking place to “neutralize” the acidity and sanitizing properties of the solution.
I’ve heard people who want to get more milage out of each batch of Star San recommending adding lactic acid to the Star San solution to increase it’s acidity (lower the pH) if the pH is found to be too high. I’m not sure if this would work. What do the rest of you say? Does lactic acid get the pH down to 1 or 2? What’s the magic pH number to keep the Star San solution under?
Mostly phosphoric acid (50%).
http://www.fivestarchemicals.com/msds/starsan.pdf
Never fear the foam! 8) …just don’t tell Kai I said that.
Edit: I have used it up to several months old without a problem.
I have kept a mixture for well over a year. Didn’t see that as a poll option…
I’ve gone as long as 6 months, could have gone longer but that consumed all I had made up.
Fred
I usually mix up 5 gallons at a time in a plastic jug (the kind that looks like a carboy) and use water that has gone through the water softener. I’ve kept it for up to 6 months w/o any issues. YMMV
I’ve gone 2 years for a spray bottle mixed with distilled water. With my tap water, though, I only use it once and get rid of it.
I also keep my old batch of StarSan around to rinse off items before I put them into the current StarSan batch. This allows me to use one 5 gal batch of StarSan for more than 5 batches. And this includes all associated sanitation needs.
No, this won’t work. Lactic acid is not strong enough to get the pH that low. It’s a weak acid with a pKa of 3.86. This means at a pH of 3.86 only ½ of the lactic acid molecules give up H+ to lower the pH. This number gets progressively less as the pH decreases. Less than 10% will be able to donate H+ at a pH of 2.86.
If you want to get the pH that low you need to use phosphoric acid, which has its first pKa at 2.15 or a strong acid like hydrochloric or sulfuric acid. But I would not want to mess with the latter two, especially if I want to be able to stick my arm in there.
The most practical solution is to make a new batch of StarSan
Kai
It works as long as its pH is less than 3.
Rather than adding lactic acid, you can “freshen it up” with some more StarSan.
Keep in mind you need a certain amount of contact time with star san and that time means “wetted”, not submerged. So a little goes a very long way…
I leave aeration stones in cloudy star san between batches. If you put an aeration stone in fresh star san, you can kiss the fresh stuff goodbye.
The official stuff
PRODUCT TECH SHEET
STAR SAN
Acid Sanitizer for dairy and food-use surface sanitation.
v BENEFITS
v Broad Spectrum Bactericide and Fungicide
v Not Affected by Organic Materials
v No Rinse Requirement When Used at 300 ppm
v Accepted by U.S.D.A. as a General Sanitizer in all Departments
v DESCRIPTION
STAR SAN is a blend of phosphoric acid and dodecylbenzenesulfonic acid. This synergistic blend
provides a unique killing system that is unaffected by excessive organic soils. STAR SAN is also a selffoaming
sanitizer. It can be applied through a foamer to produce self-adhering sanitizing foam for
external sanitation. STAR SAN is also an excellent sanitizer for hand application. Sanitizing with STAR
SAN on a daily basis will leave equipment in a acid condition that will eliminate water spotting. It is not
recommended to use STAR SAN on soft metals because of the acid nature of this product.
v PROPERTIES
APPEARANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . … ……… . . . . .DARK BROWN TO STRAW
ODOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . … . . . . . . . . . . . . . . . . . . . . . . . . .SLIGHTLY ALCOHOLIC
PHOSPHATE CONTENT AS % Phosphorus. . … . . . . . . … . . . . . … . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.8%
SPECIFIC GRAVITY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . … . . … . … . . 1.320
v GENERAL USE DIRECTIONS
All surfaces should be cleaned and rinsed before sanitizing with STAR SAN.
Directions: A dilution of 1 ounce to 5 gallons of water, STAR SAN will provide 300 ppm of dodecylbenzenesulfonic
acid. After 1 to 2 minutes contact time, drain sanitizing solution equipment thoroughly. Do not rinse. If using Star
San in CIP, proper water balance must be maintained or your pump may cavitate. If used at a rate of more than
300 ppm, a potable rinse is required.
Part Soaking: Use 1 ounce of STAR SAN per 5 gallons of water. Parts must have contact with solution for 30
seconds and put on wet. When solution begins to cloud, sweeten with Star San or Phosphoric Acid. Solution must
remain at a pH at 3 or below to maintain proper sanitizing level.
Hand Utensils: Scrape or preclean dirty utensils. Clean using a suitable detergent, following label directions. Rinse
with potable water. Soak or spray utensils/inflations with a STAR SAN ACID SANITIZER solution (1oz./5 gal. of water).
After 1 to 2 minutes contact time, drain solution thoroughly. Prepare a fresh solution daily or more often if the
solution becomes soiled or dirty.
Bulk Milk Tanks: Clean tank with a suitable detergent and rinse with potable water. Manually spray a STAR SAN
ACID SANITIZER solution (1 oz/5 gal. of water) on all surfaces to be sanitized. After 1 to 2 minutes contact time,
drain solution thoroughly.
Food Plant Use: Bulk Tanks, Vats and Utensils: Scrape or preclean dirty surfaces. Wash equipment with a suitable
detergent and rinse with potable water. Sanitize with a STAR SAN ACID SANITIZER solution (1 oz/5 gal of water) by
either brush soak or spray method. After 1 to 2 minutes contact time, drain solution thoroughly.
Awsome thank you very much guys. this site/forum is the chit.
evan
Yeah, I keep mine in a spray bottle for a long time, using tap water and I’ve had no issues. I make up a new batch when I start to run out…that could be months. Haven’t had any infected batches yet. I also keep some in a jug and make up a new batch for that when it starts to run out. I reuse it alot too.