Biodiesel and Kosher Glycerin: A look at this important fuel and its valuable byproduct

Kosher Glycerin in Demand

About 350,000 tons of glycerin are produced in the United States each year. In part because of decreased government subsidies, and certain other economic factors, kosher glycerin is harder to come by than it was previously. Along with using plant-based feedstock, making the refineries kosher, under rabbinic supervision, makes it possible to manufacture kosher glycerin and meet a growing demand. 

One of the most exciting and innovative processes spawned by 21st-century technology is that of biodiesel. Simply put, biodiesel is a replacement fuel for diesel engines. One fascinating and exciting use of biodiesel is in jet fuel; many commercial airliners have committed themselves to using SAF (Sustainable Aviation Fuel), of which biodiesel fills a prominent role. While standard diesel fuel, also called petrodiesel, is made from petroleum, biodiesel, which is nontoxic and biodegradable, is made from what are known as biomass oils.

For more information about kosher certification and Biodiesel, contact  Mordechai Stareshefsky

These biomass oils can be derived  from plant oils, such as soybean, canola and corn oil, but are so versatile that refineries can take waste products such as used cooking oil (UCO) and animal fats, and turn them into biodiesel. Even algae is being investigated as a potential source of biodiesel feedstock. 

Biofuel Refinery

Sugarcane Plant producing Ethanol for biofuel.

Of particular relevance to the food world is the fact that a co-product of biodiesel production is glycerin, an indispensable ingredient in a variety of foods, such as dried and canned vegetables or fruits, precooked vegetables, precooked pasta, rolled oats, breakfast cereals, rice or tapioca pudding, breading or batters, precooked rice products and baked goods. Glycerin helps to retain moisture, prevent sugar crystallization, and add bulk, smoothness, softness, sweetness and texture. 

Many biodiesel refineries are now looking to attain kosher certification. This is for two reasons: 

  • Biodiesel is not cost-effective to manufacture without heavy government subsidies. Congress has proven to be parsimonious and inconsistent with these subsidies, and producers are scrambling to develop ways to add value to their products, such as making the glycerin kosher by using kosher feedstock, for example. 
  • Animal feedstock, which includes animal fats, is becoming increasingly expensive; while it is highly in demand because it meets various California environmental standards for renewable sources, it can’t be used to make a kosher product. In order to produce kosher glycerin, then, the biodiesel process must use strictly plant-based feedstock. 


The Production and Kosherization Process

Biodiesel is produced by a process called transesterification, which converts fats and oils into biodiesel and glycerin, a co-product commonly used in the manufacture of pharmaceuticals and cosmetics as well as many foods. The process of making biodiesel starts with feedstock being delivered to the facility by boat or by tanker truck and stored in terminals until it is treated. About a hundred pounds of oil or fat are mixed with 10 pounds of methanol and a catalyst to form 100 pounds of biodiesel and 10 pounds of glycerin (or glycerol). 

OU Kosher rabbis not only thoroughly understand how to apply Jewish law to the products they supervise, they also make it their business to learn exactly how these products are manufactured. This often includes mastering technical intricacies that require special advanced education and training, and means that the rabbis are skilled at pinpointing the best processes and adaptations to help a company take advantage of the value-added of being able to market a product as kosher. 

In addition, OU Kosher has, of course, vast experience in helping refineries transition from non-kosher to kosher. Although each refinery is unique, the basic plan takes two steps: the cleaning of the equipment and its kosherization. Although kosherization of tanks is typically done with boiling water, this is not feasible in a biodiesel refinery for two reasons: 


  1. Many tanks are not jacketed, that is, they don’t have the ability to heat themselves, and the water therefore will not reach a boil. 
  2. The amount of water necessary to effect a kosherization will wreak havoc with the plant’s utilities – boiling and disposing of up to 5 million gallons of water is quite a challenge. 

Accordingly, kosherization of refineries is done with steam. The plant will blow in live steam through the top of the tank, and the rabbi supervising the kosherization will measure the condensate exiting below. Once the condensate displays consistent readings of 200°F and above, the tank has been effectively kosherized. 


Rabbi Mordechai Starshefsky
Rabbi Mordechai Stareshefsky resides in Lakewood, NJ with his family. He is a musmach of BMG, having previously learned in Yeshivas Rav Chaim Berlin, The Mir and Brisk. Prior to joining the OU he worked at ArtScroll as part of the team of writers elucidating Talmud Yerushalmi. His focus at OU Kosher is on Baby Formulas, Spices, Vinegars and the Beverage industry. He was one of the editors of the Halachah Yomis book published by the OU.