How much Star San per gallon?
Five Star's label is 1 ounce per 5 gallons of water — 1.56 mL per liter, or 5.9 mL in a gallon, which is a teaspoon and a quarter. Everything else is that ratio scaled to the water in front of you:
| Water | Star San | Nearest US measure | Measure is off by |
|---|---|---|---|
| 16 oz spray bottle | 0.74 mL | ⅛ tsp | −17 % |
| 1 liter | 1.6 mL | ¼ tsp + ⅛ tsp | +18 % |
| 1 gallon | 5.9 mL | 1 tsp + ¼ tsp | +4 % |
| 10 liters | 16 mL | 1 Tbsp | −5 % |
| 5 gallons | 30 mL | 1 fl oz | exact |
| 20 liters | 31 mL | 1 fl oz | −5 % |
Label dose, 1 fl oz per 5 US gal = 1.5625 mL/L. US measures rounded to the nearest ⅛ teaspoon, or ⅛ fl oz from one ounce up. Computed by this page's engine.
The ratio is simple and still gets mangled in conversion. Coldbreak's mixing table says "1 gallon: 1 teaspoon", which is 17 % short of the label. The metric figures on the forums run from 0.75 to 3 mL per liter — from 48 % of the label dose to 1.9 times it — and the number that's actually right, 1.56, doesn't appear on any of the pages that rank for the question.
Small batches are where spoons fail. A 16 oz spray bottle wants 0.74 mL; the nearest spoon, ⅛ tsp, is 17 % light. A 3 mL oral syringe from any pharmacy measures it exactly.
Is more Star San better?
No — and the label says precisely where "more" stops being free. At 1 oz per 5 gallons the solution carries 300 ppm of its active acid, dodecylbenzenesulfonic acid; that concentration is what the no-rinse claim is registered at. Five Star's own technical sheet: "If used at a rate of more than 300 ppm, a potable rinse is required." A double-strength bucket is 600 ppm, and a mix you have to rinse with tap water is no longer the no-rinse sanitizer you bought.
The foam is sanitizer solution, and at the label dose what it leaves in a fermenter is within the residue the no-rinse registration allows — that is the whole reason the slogan is true. It's a statement about 300 ppm, not about Star San at any strength. Mix it by the label and leave the foam; mix it by eye and you've lost the thing that made the foam harmless.
How long does Star San need to sit?
Six sources, four different answers — from thirty seconds to five minutes:
| Source | Contact time |
|---|---|
| Northern Brewer | "30 seconds" |
| Beercraftr | "one minute of contact time" |
| Five Star's product page | "at least 1-2 minutes" |
| Star San EPA label | "surface must remain wet for one minute" |
| Five Star's 2026 craft chart | "5 minutes" (immersion) |
| Homebrew Finds | "Required contact time is five minutes" |
Quoted from each source, 25 Sep 2026.
The one that settles it is the EPA-registered label, because that's the document the product's sanitizing claim is made under: keep the surface wet for one minute, then drain without rinsing. The five minutes on Five Star's chart is for parts soaking in a bucket, which is also sensible for anything with crevices — a spigot, a bottling wand. Thirty seconds matches an old Five Star instruction for small parts soaking in solution; don't use it for a fermenter you're swirling by hand.
Is cloudy Star San still good? How long does it last once mixed?
Five Star's current FAQ blames cloudiness on age "or because of hard water minerals reacting to the chemical" and, in a quote Homebrew Finds got from the company, says clarity "is not considered an issue". The page telling you cloudy means dead is repeating Palmer's How to Brew, which ties cloudiness to the pH rising above 3.5. Both describe real things: hard water can cloud a perfectly acidic solution, and a solution that has lost its acid can stay clear. Cloudiness isn't the test; pH is. A pack of pH strips settles it in ten seconds — Five Star's older sheet used 3 or below.
As for keeping it: the same FAQ says Star San "must be used immediately. We do not recommend using it if has been in solution longer than an hour." Plenty of brewers keep a bucket for weeks and check the pH, and the older sheet described doing exactly that — but the one-hour answer is the manufacturer's, and it's why this page sizes a batch to the job rather than to the bucket.
Filling a 6.5-gallon bucket every brew day uses 1.3 oz of Star San: a 32 oz bottle lasts 24 batches. A gallon swirled around the same bucket — lid on, rolled, drained — wets every surface a full bucket does, and the bottle lasts 160. Fill what has to be filled (a keg's dip tube, a racking cane) and swirl the rest.
Do you have to clean before you sanitize?
Yes, and they're different jobs. A cleaner — PBW, One Step, OxiClean — lifts the soil: krausen rings, hop gunk, dried beer. A sanitizer kills what's left on a surface that's already clean, and it can't reach a bacterium sitting under a film of protein. Clean, rinse, then sanitize — a sanitizer used as a cleaner is how a brewer who "sanitized everything" still ends up with an infection (the off-flavors guide covers what one tastes like).
How much PBW per gallon?
Five Star's 2026 chart: ¾ oz per gallon for fermenters and kegs (5.6 g/L), 1–2 oz per gallon for kettles (7.5–15 g/L), 30 minutes, 120–140 °F for a fermenter, then rinse. PBW is a powder, so those ounces are weight — a kitchen scale, not a spoon. Two numbers you'll meet that disagree: Five Star's product page says "3-4 ounces per gallon" for fermenters, four to five times its own chart, which reads like a "¾" that lost its fraction bar (our inference); and a retailer's "1 tablespoon per gallon" is a volume of powder, which depends on how it packs.
PBW is alkaline — pH 12 at 1 % — so gloves and eye protection, and Five Star says not to leave it in a keg past 8–12 hours or it can leave a scale. For dried-on krausen, the product page's own advice is a 4-hour soak at 140 °F, or overnight.
How much bleach per gallon to sanitize?
It depends on the jug, and nearly every homebrew source assumes the old one. Palmer's rule — a tablespoon per gallon, "rinsing is supposedly not necessary at this concentration" — matched the 2011 Clorox label, which called a tablespoon of 5.25 % bleach per gallon 200 ppm (the engine makes it 194). Clorox is 7.5 % now, and its current label asks for 2 teaspoons per gallon for 185 ppm. Palmer's tablespoon of today's bleach is 278 ppm:
| Bleach strength | For 185 ppm, per gallon | Per liter | A tablespoon per gallon gives |
|---|---|---|---|
| 5.25 % | 1 Tbsp | 3.7 mL | 194 ppm |
| 6 % | 2 tsp + ½ tsp | 3.3 mL | 222 ppm |
| 7.5 % | 2 tsp | 2.6 mL | 278 ppm |
| 8.25 % | 1 tsp + ½ tsp + ¼ tsp | 2.4 mL | 305 ppm |
ppm available chlorine, calibrated on the current Clorox label (2 tsp/gal of 7.5 % = 185 ppm); reproduces the 2011 label's 5.25 % figure within 3 %. The dose column targets the current label's 185 ppm, which Clorox calls "equivalent performance to 200 ppm". Unscented bleach only. Computed by this page's engine.
At the label dose, Clorox's USDA directions don't require a potable rinse "provided the equipment … are adequately drained"; two minutes wet, and mix it daily. Above it, the label no longer says you can skip the rinse — and chlorine is what makes the medicinal, band-aid chlorophenols in beer, whether it arrives in the brewing water or as residue on the fermenter wall. If you use bleach, measure it by the strength on your jug, and rinse when in doubt.
Why this page won't calculate bleach and vinegar
The bleach-and-vinegar method has a real chemical basis. Bleach sanitizes mostly as hypochlorous acid, and the CDC's disinfection guideline notes that chlorine's efficacy "decreases with an increase in pH" — so acidifying the solution makes it kill much faster. The same guideline warns of "toxic chlorine gas when mixed with ammonia or acid", and Washington's Department of Health is blunter: "When chlorine bleach is mixed with an acid, chlorine gas is given off."
- Star San is phosphoric acid. Its EPA label: "Do not mix STAR SAN ACID SANITIZER with Chlorine Sanitizers or Chlorinated Cleaners. A harmful gas is formed." The CDC has documented chlorine gas poisonings from bleach mixed with a phosphoric-acid cleaner.
- Rinse between them. Bleach-cleaned gear goes through clean water before it meets Star San, and vice versa.
- PBW is caustic (pH 12). Gloves and eye protection, and never mix a cleaner and a sanitizer "to save a step".
- Iodophor goes in cool water — the label says never hot — and, per Palmer, it stains plastic with long contact.
The method's defenders dilute the bleach first and add the vinegar last to keep the gas down. Keeping it down isn't the same as not making it, and this site's terms say never mix cleaning chemicals. Star San and iodophor exist precisely so you don't need to acidify bleach. The calculator gives you bleach alone, at the label dose, by the strength on your jug.
How much iodophor for 12.5 ppm?
BTF Iodophor's label gives two recipes for the same 12.5 ppm: ¼ oz per 2½ gallons, or 1 teaspoon per 1½ gallons. They aren't the same. At the label's 1.6 % titratable iodine the first is exactly 12.5 ppm and the second is 13.9 ppm — 11 % stronger, harmlessly, since the label's other strength is 25 ppm. Per gallon it's 3 mL, about ½ tsp + ⅛ tsp. Two minutes of contact on the label (one on the product page), no rinse, and the solution is good as long as it stays amber — mix it daily.
One Step and OxiClean: cleaners, not sanitizers
Both are sodium percarbonate — oxygen cleaners. L.D. Carlson says it outright about One Step: "it is not a certified sanitizer and it is recommended that a certified sanitizer is used in conjunction." Its dose is a tablespoon per gallon, two minutes. OxiClean Free's hard-surface directions are "scoop to line 4 per gallon", 5–30 minutes, then rinse, and use the solution within 6 hours. Church & Dwight doesn't publish what the scoop holds, so this page doses OxiClean in scoops and won't pretend to know the grams.
Printable dosing chart
Every product at its label dose, for the sink or the inside of a cabinet door. Bleach at the three strengths you'll find on a shelf.
| Product | 1 gal | 5 gal | 1 L | 10 L | Contact | Rinse |
|---|---|---|---|---|---|---|
| Star San | 1 tsp + ¼ tsp | 1 fl oz | 1.6 mL | 16 mL | 1 min wet | no |
| Saniclean | 2 tsp | 1⅝ fl oz | 2.6 mL | 26 mL | 3 min | no |
| Iodophor, 12.5 ppm | ½ tsp + ⅛ tsp | 1 Tbsp | 0.78 mL | 7.8 mL | 2 min | no |
| Bleach 6 % | 2 tsp + ½ tsp | 2⅛ fl oz | 3.3 mL | 33 mL | 2 min wet | no |
| Bleach 7.5 % | 2 tsp | 1⅝ fl oz | 2.6 mL | 26 mL | 2 min wet | no |
| Bleach 8.25 % | 1 tsp + ½ tsp + ¼ tsp | 1½ fl oz | 2.4 mL | 24 mL | 2 min wet | no |
| PBW (cleaner) | 0.75 oz | 3.75 oz | 5.6 g | 56 g | 30 min | yes |
| One Step (cleaner) | 1 Tbsp | 2½ fl oz | 3.9 mL | 39 mL | 2 min | no |
| OxiClean Free (cleaner) | 1 scoop to line 4 | 5 scoops to line 4 | 0.26 scoops to line 4 | 2.6 scoops to line 4 | 5–30 min | yes |
Each manufacturer's label dose; bleach at the Clorox label's 185 ppm available chlorine, unscented only. Clean first, rinse, then sanitize. Never mix bleach with Star San, vinegar or any acid. US spoons rounded to ⅛ tsp — for a spray bottle, use a syringe. Computed by this page's engine.