Sanitization: Iodophor Versus Star San

Proper sanitization is the key to cold-side success when it comes to brewing beer. Without sanitization, there’s no telling what could potentially infect and or ruin our batch of beer. The purpose of this article is to take an in-depth look at the industry’s two most popular sanitizing solutions available to homebrewers.

When it comes to sanitizing solutions, iodophor and Star San are two of the most popular options available to homebrewers. Both of these products are highly effective at eliminating bacteria and other microorganisms that can cause contamination and spoilage in beer. However, there are some key differences between iodine and acid-based sanitizers that homebrewers should be aware of when choosing a solution.

For the purposes of this article, I’m going to focus on iodophor sanitizers, BTF Iodophor and Star IO, and acid-based cleaner, Five Star Star San. I have used both products extensively in my home brewery in a wide variety of applications. Each product has its own drawbacks and advantages. Let’s get into some of the details.


Iodophor is a low-foaming sanitizing solution that contains iodine, a powerful antimicrobial agent that is highly effective at killing bacteria, viruses, and other microorganisms. Iodophor sanitizers work by denaturing the proteins in microorganisms, causing them to break down and die. It is a very popular choice for sanitizing equipment and surfaces in the brewing industry, as it is relatively inexpensive and very easy to use.

Iodophor Benefits

  1. Effective against a wide range of microorganisms: Iodophor is a powerful sanitizer that can kill a broad range of microorganisms, including bacteria, viruses, fungi, mold, and yeast. 2 minute contact time is recommended for full effectiveness.
  2. No-rinse formula: One of the biggest advantages of iodophor is that it doesn’t require rinsing after use, making it a convenient option for homebrewers. Note, certain concentrations DO require rinsing.
  3. Long-lasting: Iodophor can remain effective for up to 24 hours after being mixed, making it a good option for larger brewing or fermentation projects.
  4. Non-corrosive: Iodophor is non-corrosive to most metals, making it a safe choice for use with brewing equipment.
  5. Low foaming: Iodophor is best for use on pump, spray, and CIP applications.

One of the main advantages of iodophor is that it leaves a residual film on surfaces that can continue to kill microorganisms even after the solution has been rinsed off. I’ve heard some homebrewers complain about this residue however it’s not something I have ever had a problem with personally.

Iodophor No-Rinse Concentrations

The two most popular suppliers of iodophor sanitizers are BTF and Five Star. Depending on the product/brand, you will have different recommended concentrations and instructions. BTF Iodophor calls for .5 ounces per 5 gallons (12.5 ppm) to be used as a no-rinse sanitizer. IO Star calls for 1 ounce per 5 gallons (25ppm), to be used as a no-rinse sanitizer. I would not assume the chemical makeup of different brands is the same. Equipment should be left to air dry after sanitizing.

Please note: Any concentration higher than the recommended range by each product should be followed with a rinse of potable water. Be sure to read the label on your product for recommended dosage instructions.

Iodophor Downsides

There are some downsides to using iodophor as a sanitizing solution. Iodophor can leave a yellow-brown stain on plastic equipment, which can be difficult to remove. My silicone and vinyl tubing will sometimes take on a pinkish hue after sanitizing with iodophor, however, it usually returns to its normal color in a few hours. Iodophor also has a strong aroma that can still be smelled in a fermenter even after it has been drained. Again, some homebrewers claim they can taste the iodophor in their final beers, however, I have never been able to detect this.

Star San

Star San is a no-rinse acid-based sanitizer that is highly effective at eliminating bacteria and other microorganisms. It works by lowering the pH of the solution to a level that is too acidic for microorganisms to survive. Star San is popular in the brewing industry because it is easy to use and does not require rinsing, which can save time and water. Star San has a shorter shelf life and must remain at or under a pH of 3.5 to be effective.

Star San Benefits

  1. Quick and effective: Star San is a fast-acting sanitizer that can eliminate bacteria, microorganisms, and yeast, making it ideal for quick cleaning and sanitizing equipment. 1 minute contact time is recommended.
  2. No-rinse formula: Star San doesn’t require rinsing after use, making it a convenient option for homebrewers.
  3. Foam-based: Star San is a foaming sanitizer, which means it can penetrate hard-to-reach areas and provide better coverage than liquid sanitizers.
  4. No odor or taste: Unlike some other sanitizers, Star San doesn’t leave any odor or taste behind, which is important for maintaining the flavor of your beer or other fermented products.

Star San Downsides

There are some downsides to using Star San as a sanitizing solution. For one, it is not as effective as iodophor sanitizers at eliminating some types of microorganisms, such as mold, fungi, and wild yeast. Additionally, because it is an acid-based sanitizer, it can corrode some types of equipment if not used properly. While the foaming ability of Star San has its benefits, it is not the most functional sanitizer when it comes to CIP applications.

If you’d like to stick with acid-based cleaners, Five Star’s Saniclean is a low-foaming version of Star San that is better suited for CIP applications. Saniclean is also an odor remover.

Final Thoughts

In the end, the choice between iodine and acid-based cleaners comes down to personal preference and the specific needs of the brewer. Both of these products are highly effective at eliminating microorganisms and preventing contamination and spoilage in beer. I use both products on brew days depending on the application. I always keep a Star San spray bottle handy for quickly sanitizing small parts or components. When it comes to sanitizing my fermenter, I always run a CIP loop with an iodophor sanitizer.

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