Have you ever tried a beer that smells like medicine and tastes like band-aids? If so, it’s because the beer contains chlorophenol. Chlorophenol can give the beer a plastic taste, smoky flavor, chlorine disinfectant taste, or band-aid taste.
What is Chlorophenol?
Chlorophenol is a toxic organic compound that has a significant impact on beer. It can make your beer taste like plastic, smoke, chlorine disinfectant, or band-aids, which is very harmful to the quality of your beer. Additionally, chlorophenol is a stronger bactericide and preservative than phenol and is also an important industrial raw material.
Chlorophenol is harmful to the human body. It can be absorbed through skin contact, causing damage to the liver, kidneys, and lungs. If chlorophenol is dissolved in a solvent, it becomes even more toxic. Inhalation of chlorophenol can lead to rapid breathing, increased blood pressure, fever, and other symptoms.
How is Chlorophenol Produced?
Chlorophenol is formed when phenol reacts with chlorine or chloramine in the water used for brewing. It causes off-flavors in beer and is detected at relatively low levels.
Where do the Chlorine and Chloramines in Beer Come From?
In normal circumstances, we don’t want any chlorine-related compounds in beer. To eliminate them, it’s important to understand their sources:
1. Use of chlorinated water: Urban tap water is disinfected by adding a small amount of chlorine. If chlorinated tap water is used in brewing or for cleaning brewery equipment, a small amount of chlorine or chloramine may end up in the beer.
2. Wild yeast: Some wild yeasts contain small amounts of chlorine or chloramine, which can affect the beer’s flavor once they enter.
3. Chlorine-based cleaning agents: Residual chlorine may be present on the equipment’s surface if chlorine-based cleaning agents are used to clean brewing equipment and fermentation tanks.
How to Avoid the Production of Chlorophenol?
Since chlorophenol is a compound formed by the combination of phenol and chlorine, it’s important to remove chlorine from beer. The primary source of chlorine is brewing water. Here are some ways to prevent chlorine from entering the beer:
1. Use a carbon filter to purify all brewing water. Note: The filter must be used at the specified flow rate; otherwise, some chlorine or chloramines may remain in your brewing water.
2. Avoid using chlorinated water for brewing or washing equipment that will come into contact with the beer. If you must use chlorinated water, let it sit exposed to air overnight to allow the chlorine to naturally dissipate.
3. Add Campden tablets (potassium metabisulfite) to the brewing water. Campden tablets neutralize chlorine and chloramines in the brewing water.
4. Some brewers choose to use reverse osmosis water or distilled water to avoid chlorine and chloramines in their beer.
5. If you use a chlorine-based disinfectant (such as bleach) to sanitize your equipment, make sure to thoroughly rinse the equipment after disinfection. This step is crucial.
6. Consider the yeast selection. Try to choose yeast strains with less chlorine sensitivity.