Mass, volume, and Pomegranates

July 27, 2017

Posted: November 5, 2016

I don’t know if it is harder to spell pomegranates, or to embark on the arduous journey of peeling these giant fruits without staining everything in sight.  Despite its unforgiving nature, this noble fruit, a true jewel of autumn, has found its way from the Greater Middle East region, through the Silk Road and sea routes to the solitary bastion of modern trade near USC: the Ralphs’s on Vermont and West Adams.  For $5 (sometimes $4), two pomegranates can be bought, but really the opportunity to test one’s patience is priceless.  If you have ever committed the cardinal sin of picking a bland pomegranate, then rest assured that basic mathematics can help you overcome your questionable judgement.

Scientifically speaking, a pomegranate seed is called an ‘aril’, and no, larger pomegranates do not have larger arils [1].  Consequently, a larger pomegranate will give you more arils, but it’s not just quantity that we are after.  Unless you are a masochist, chances are you want a juicy pomegranate, so the parameter to maximize is density.  Wetzstein et al found that the weight and volume of a pomegranate have a very strong linear relationship.  And since density = mass/volume, picking the largest fruit seems to be an intuitive solution.  However, the juice content is not as strongly related to the total weight of the fruit.  So don’t be fooled by a larger fruit, and try to pick the ones which feel heavier than similarly sized fruits.  I’ve mastered the two-hand test which involves comparing two pomegranates side by side and eliminating the one which is less dense.  You can keep using this process of elimination to find the best pomegranate for sale, or until you’ve sufficiently weirded out every other shopper by holding two pomegranates and staring off into the distance.

[1] Wetzstein, Hazel Y., et al. “Characterization of attributes related to fruit size in pomegranate.” HortScience 46.6 (2011): 908-912.


Published on July 27th, 2017

Last updated on August 10th, 2017