An interesting issue has come up with a by-product of biodiesel and whether it meets strict Jewish dietary laws.

Glycerin, made plentiful from what used to be ramped-up biodiesel production, is now being used in a variety of foods. Sweet, natural glycerin is being used in many food products. And Autobloggreen says the fact that the glycerin could be coming from either plant or animal sources is causing some concern for those rabbis verifying how kosher that glycerin is:

This is not easy to figure out, especially if the biodiesel was made from waste restaurant fats – one important question: “was the oil used to fry pork?” – or if the glycerin is a blend of many biodiesel production streams. Over time, the rabbis have worked with biodiesel production facilities to track the fat source in order to verify just what is in the glycerin and, thus, can confidently say whether the resulting foods are kosher or not.

The best news is, biodiesel is always kosher to use in your diesel engine … and you don’t even have to cut off the end of your tailpipe!