Tomatoes have lost their flavor.  The explanations for why this has happened usually focus on tomatoes being hot house grown, over-pampered with fertilizers and being picked unripe and shipped long distances.  A new and perhaps better explanation comes as a surprise and gives hope for the tomato of the future.

The June 29, 2012 issue of the journal Science finally tells us why some tomatoes taste better than others.

For the last 70 years, plant breeders have endeavored to create tomatoes that are uniform red in color. The goal has been to eliminate “shoulders”— the dark green collar where the fruit attaches to the stem, which previously stayed green even after the rest of the tomato had ripened.  People are more apt to purchase uniformly red tomatoes rather than their green-shouldered neighbors because the later do not look ripe.

This process of color improvement started early in the last century when a mutant tomato was discovered that had a “uniform ripening trait.” This led to the 1930 release by the Fargo, North Dakota US Agricultural Experiment Station of a new variety of tomato called the “All Red.”  In the following 80 years, plant breeders have successfully transferred this trait to almost all tomatoes.

The recent Science report reveals what went wrong.  The All Red tomato and its myriad descendents no longer possess a functioning version of the gene that produces green shoulders.  It turns out that the additional chlorophyll in the shoulders continues to make sugar from sunlight even as the rest of the tomato ripens.  Green shouldered tomatoes contain about 20 percent more sugars than their all red relatives. As a result, they taste sweeter because they are sweeter.

Thus the secret to finding a great-tasting tomato is to look for a ripe tomato with green shoulders.  Yet we might call this a shopping Mission Impossible because you will be lucky to find one.  Shouldered tomatoes are incredibly rare, which is a measure of how consumer demand has shifted our food supply.  The only shouldered tomatoes you will find these days come from heirloom seeds.