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What Is the Ester of Wood Rosin?

Nicholas Johnson

Ester of wood rosin, or ester gum, is a food additive in many fruit juices and sodas. The substance is acidic and acts as a stabilizer or a thickening agent for certain foods and drinks. Produced from tree stumps, ester of wood rosin has shown no major health effects in small quantities.

Some sports drinks use glycerol ester of wood rosin to keep the flavor consistent from beginning to end.


Wood rosin is a substance extracted from the stump of the long-leaf pine tree. Long-leaf pine trees are commonly found in the southeastern United States. The rosin is a dense substance that contains several different harmless abietic acids. Wood rosin is combined with several other substances to create ester gum, which is also referred to as the ester of wood rosin. Ester gum acts as a thickening agent and can commonly be found in ice cream and chewing gum.

Use in Beverages

Fruit drinks and fruit sodas commonly use fruit oils to achieve a more robust natural flavor. However, fruit oil is unable to remain mixed with a water-based carbonated soda or fruit juice. Glycerol is added to ester of wood rosin to create glycerol ester of wood rosin, which acts as an emulsifier. The new substance lightly thickens the beverage to suspend the fruit oils homogeneously.

Health Studies

Several health studies have been performed pertaining to the health effects of glycerol ester of wood rosin. In rat trials, only a few fatalities were reported at extremely high dosages. Long-term studies using low dosages with beagles showed only an adverse increase in weight until a concentration of 1 percent was used. The Food and Drug Administration has mandated that products contain no more than 100 parts per million of glycerol ester of wood rosin in commercial products.

Human Studies

In rare cases, ester of wood rosin has been known to cause allergic reactions in humans. Since ester gum is a major ingredient in periodontal equipment, patients with repeated exposure developed a sensitivity to the rosin. However, women who were tested using rosin-based cosmetics and toiletries tested almost entirely negative for rosin sensitivity.