Five Star Chemicals Star San is a great no-rinse sanitizer for brewing that we highly recommend. In fact, we use Star San for every single beer we brew, ferment, transfer, keg, and bottle. In fact, Star San is so effective that we have moved from mixing full 5-gallon batches for each time we use it to mixing much smaller batches that we use in a spray bottle and in our DIY Keg and Carboy Washer, which makes a bottle last much longer.
Because the Star San instructions only include the amounts needed for a full 5-gallon batch, we thought it would be helpful to share common Star San mix ratios and create a simple Star San calculator that will help you determine how much Star San must be added to water to properly dilute the sanitizer.
Per the instructions on the bottle, Star San is diluted at a rate of 1oz of Star San per 5 gallons of water. This gives us a ratio of 1:640, which we will use to help you determine the amounts for each use. Once we get below one gallon, we switch from imperial measurements to metric measurements for the Star San, which will allow us to use a 5ml syringe to measure smaller amounts of Star San.
Star San Mix Ratios
Here are our most common Star San batch sizes and the amounts needed:
- 5 Gallons Water + 1oz Star San
- 2.5 Gallons Water + 0.5oz Star San
- 1 Gallon Water + 0.2oz Star San
- Standard Spray Bottle: 16oz Water + 0.74ml Star San (use a 5ml syringe to measure approximately ¾ a ml of Star San).
- ½ Standard Spray Bottle: 8oz Water + 0.37ml Star San
Star San Mix Ratio Calculator
If the amounts above don’t give you the mixture you need, here is a simple calculator that you can use to figure out the right amount of Star San to use:
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