Have you ever used Star San for sanitizing your brewing equipment? If you have, then you know it is an effective sanitizer AND that it also has the propensity to foam. Actually, the last part would be an understatement; it foams A TON! Many first time users of the product freak out and attempt to “rinse” the foam away, only to find that this can actually make it worse! So, what is the deal with the foaming, and is it something to worry about as homebrewers and wine makers?

Why Does it Foam?

Believe it or not, the foam is actually there for a reason. For starters, the foam itself is an active sanitizer. This features helps you sanitize in hard to reach places. Think of the neck or your carboy, or the top of your corny keg.

Second, the foam actually has some detergent properties as well. This is a GREAT feature, that some users miss! This detergent property allows you to sanitize a surface even if you miss a few spots while cleaning. This is not a reason to be haphazard with your cleaning. It does provide you a level of insurance though that you don’t have to be perfect with your cleaning.

Will the Foam Hurt My Homebrew

Simply put, NO! The foam from Star San will not hurt your homebrew. Five Star Chemicals, the company behind Star San, actually penned a slogan for this: Don’t Fear the Foam! While it may seem strange, nothing is wrong with dumping your fresh wort into a carboy/keg full to the brim with foam. Trust us we’ve done it hundreds of times! Not only is it ok to do this, it is actually GOOD for the yeast.

Good for the yeast? Yes, you heard that correct. The main ingredients found in Star San (DDBSA and Phosphoric Acid) can be GOOD for your yeast. How you ask? Well it’s all a bit too scientific for me, but basically when it is mixed with your wort, the pH of the Star San increases. As the pH increases, the DDBSA and Phosphoric Acid start to break down. When they break down, they actual begin to act as a yeast nutrient!

I Still Can’t Stand It. How can I reduce the Foam?

Reducing the foam created from Star San is easy to do if you follow these few tips:

1. Use the Proper Solution Ratio

While obvious, it needs to be stated! If you use too much Star San you’re going to get more foam. The correct solution ratio is 1 oz Star San to 5 gallons of water.

2. Don’t Agitate It

Treat Star San like an angry bear, the less you bother it, the less riled up its going to get! When it comes to how you treat your Star San, this means you want to avoid agitating the solution. Dumping Star San out of your bottles? Pour slow as opposed to tipping the bottle over and dumping fast. Transferring Star San from one vessel to the next with a racking cane/auto-siphon? Make sure your tubing snakes down to the bottom of your target vessel and doesn’t splash. The less you agitate your Star San, the less foam it will create.

3. Mix Properly: Water THEN Star San

I’m sure you remember chemistry class from High School? If you do, you’ll remember that the teacher said to always pour acid INTO water, and not the other way around. The same is true when it comes to mixing water and Star San. If you pour water on top of your Star San, you’re going to get bubble city. Fuhgeddaboudit! Do what your teacher taught you, and pour your Star San into a bucket pre-filled with water. To mix it in, take a long spoon or paddle and stir slowly (remember rule #2 above).

4. Use An Alternative Sanitizer

If you’ve tried these tips and still can’t reduce the foaming, try a different sanitizer. Five Star Chemicals makes two other products for sanitizing that will not foam: Saniclean and Io Star. They are great products with different chemical make ups, that will get the job done without the foam.

Cheers!
Bryan