Hey Matt Man:
When I'm out working in my wood shop, there are certain materials that need special handling. Things like glycerol ester of wood rosin just seem to scream out "avoid breathing fumes," "wear protective gloves." Then when I'm done with my project, I sit back and take a long cool drink of Minute Maid lemonade and to my horror see glycerol ester of wood rosin listed in the ingredients, right after the modified corn starch! What the heck is glycerol ester of wood rosin, and what is it doing in my lemonade?
-- Tim, Poway
We checked Grandma Alice's lemonade recipe, but it didn't include corn or trees, so I guess this demands an inquiry. Glycerol ester of wood rosin is sometimes listed as ester gum, though that doesn't make it sound much tastier. In fact, Grandma claims she went to high school with somebody named Ester Gum. Anyway, whatever you call it, the stuff is a (food-grade) rosin byproduct of wood pulp processing included in most citrus-flavored drinks. It is a solvent that keeps citrus oil suspended in water and gives it the proper density. We never did find out what "proper" means, exactly. Lemons, water, and sugar seem proper to us, but the Minute Maid is richer than we are, so obviously we're missing something.