Ester Gum Posted on 9th November 201527th July 2021 by ThePD (The Project Definition) Ester Gum is a resinous ester or mixture of esters made from rosin or rosin acids and a polyhydric alcohol such as glycerine or pentaerythritol. Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window) Related Posted in Substance and tagged chemical. ThePD (The Project Definition) ThePD has been developing the Preferred Project Definitions based on the actual project execution and operation experiences and knowledge with the Project Language, and sharing with you daily basis.