If you mix PBW according to the directions how long will the solution remain capable of destroying microorganisms? Can you keep it for a month and still have it be effective?
Thanks in advance for your reply.
PBW does not destroy microorganisms. PBW is a non-caustic alkaline cleaner intended for organic soil removal. It will clean out carboys, brew kettles, etc of organics. It should be a one use cleaner. I have heard of using PBW as a soaking cleaner in various carboys. You might be able to transfer the solution from carboy to carboy to continue to remove organic soils, but it is more effective to make up a fresh batch every time.
Acid 5 is a nitric/phosphoric acid blend used to remove inorganic soils such as beer stone. Be careful using this acid. It can hurt you. Gloves and goggles are required for safe use.
StarSan and SaniClean are acid anionic sanitizers. They are not cleaners. The vessel should be cleaned with PBW, either by soaking overnight or with mechanical scrubbing. Rinse well. Then just before liquid id added, StarSan, diluted to the correct ratio, should be used to coat the inner surfaces of the vessel. A 10 minute contact time is plenty. Then you can transfer in the liquid. DO NOT RINSE.
If you dilute Star San with distilled water the mixture will last for quite a long time. You can check pH or contact Five Star to get a titration kit to accurately judge the effectiveness of the solution over time. The titration kit will also test for PBW.