Iodine Life Span in H2O

[Alphaacid]

Once you mix Iodine (Star-San), how long before it become ineffective?

[Thirsty_Monk]

You have a couple of hours to my opinion.

[AnthonyB]

Star San is phosphoric acid and dodecylbenzenesulfonic acid. The phosphoric acid simply lowers the pH of the solution to an active range for the DBSA to do its work.

Iodophor, which is an iodine based product, is different.

Both of these products have different shelf lives once mixed. For StarSan, as long as you keep the pH of the solution below 3, it will continue to be effective.

[Dean of Clean]

iodine stability

Once you mix Iodine (Star-San), how long before it become ineffective?

Iodine is in the same class of sanitizers as chlorine and such, (Halogen), and therefore should be treated the same. Iodine is challenged by sunlight, freezing temperatures, and aerosol conditions(atomizing causes lack of active material). If you have reasonable conditions in the brewery, I would say a prepared solution like in a spray bottle would be ok for three or four days, and you could check it with test strips or PAO titration. Dean of Clean

[Bainbridge]

It also really likes to crust onto things like chrome plating. Oh and galvanized steel. We left a large bottle brush we use on our racking arms in our soaking tub overnight once and the next morning were like "Wait, where'd all the yellow go???" Crusted onto the twisted steel handle of the brush. So if you've got a parts tub you're soaking things in, over time it'll crust onto tailpieces, beer nuts, sanke taps, anything not rubber or stainless really. Course star san also likes to eat the chrome right off your parts, so there's that.

EDIT: Derp. Not star san. PAA. PAA eats chrome. Star san makes all your vinyl hoses clouded and slippery.

[BrewinLou]

Agree with some of what was said, depends on Temp. In a sealed clean tank it will last a while, in a bucket on the floor not long depending on the temp, and what you plan to use it for. Cheers