Double, Double, Toil and Trouble: When One Boiler Serves Kosher and Non-Kosher Production

One of the more challenging considerations when evaluating a factory that produces both kosher and non-kosher is dealing with their shared utilities, such as a common boiler. If a factory produces both kosher and non-kosher products, even if the products are made on separate lines or in completely separate parts of the plant, this can still be problematic, if they share a boiler. If the steam or hot water that is used to heat the non-kosher kettles is returned to the boiler and then reused throughout the plant, in effect both the kosher and non-kosher kettles are being heated with the same water.

At first glance, it would appear that a shared boiler would not pose such a great problem. After all, the steam or hot water never directly touches any of the food; not the non-kosher food nor the kosher food. Rather, it simply circulates through the jackets of the kettles, always remaining segregated from the actual food. One might think that since the steam follows its own special path, never converging with the food, it will never become contaminated. However, kosher law dictates that we view the pot of food and the steam that heats it, as being cooked together. If the food is non-kosher, the steam will become non-kosher as well, and it may not subsequently be used to heat the kosher kettles.

So what can be done to alleviate this concern? There are several options.

  • First we must determine which non-kosher products pose a concern in the first place. If the percentage of non-kosher ingredients in a particular production is very small, although the overall product must be labeled non-kosher, it may not pose an issue with the steam. The rabbinic coordinator (RC) who oversees the plant or the rabbinic field representative (RFR) who visits the plant can help you determine which kettles will or will not pose a problem.
  • If the steam does become non-kosher, one can avoid the issue by not returning the condensate to the boiler. If instead of returning the condensate, it is sent to the drain, the boiler will remain kosher.    
  • Another possibility is to ensure that the water in the boiler is non-potable. Non-potable water will not become non-kosher, and may be circulated around both the kosher and non-kosher kettles. Sometimes, the regular boiler treatments alone are sufficient to foul the taste of the boiler water to such a degree. However, additional chemicals are often needed. One chemical that is often recommended for this purpose is Bitrex (Denatonium Benzoate). This very potent chemical already at 5 ppm will make the boiler water completely undrinkable. Usually, a system for metering in the chemical is necessary to ensure that the boiler always remains at the appropriate concentration.

Rabbi Eli Gersten serves as OU rabbinic coordinator and recorder of OU policy. He is a regular contributor to BTUS.