Our Margarita Tree

A Key lime tree

In 1895 John Bearss created the Persian lime in his nursery in Porterville, California. He was looking to make a lime that was bigger, hardier, juicier, seedless, more easily transportable and grew on trees without thorns. In this he succeeded. But it came at the cost of what matters most in a cocktail—the flavor.

The Persian lime is also known as the Bearss or Tahiti lime. It is what you are most likely to find at your local grocery store in the United States. It is large, green, with relatively low acidity, and is less aromatic and bitter than the Key Lime. It is a cross between the Key lime and the lemon.

A bowl of Key limes

The Key lime is also known as the West Indian lime, bartender’s lime, Omani lime, or Mexican lime. Its name comes from its association with the Florida Keys. (Sadly, when a hurricane wiped out Florida’s Key lime trees in the 1920s, they were replaced with Persian lime trees.) In historical cocktail recipes that date back to Prohibition and before, the Key lime is almost certainly what was intended. Also, cocktails that hail from South America, such as the Pisco Sour and the Margarita, originated with the Key lime.

The Key lime is smaller than the Persian lime and is spherical and yellow when ripe. It has a higher acidity and a stronger aroma than the Persian lime with a tart, floral juice.

Taste is, of course, a matter of opinion. In a side-by-side test of the fresh squeezed juice between home-grown Key limes and limes from the store, we felt the Key lime to be far superior. It was sweeter, fuller and less bitter. It made an astonishing difference in taste to our simple Sour cocktails when we switched to using our home-grown Key limes—the Daiquiri, Bennett Cocktail, Pisco Sour and Margarita. We also preferred it in the Last Word. But in a side-by-side test of two Mai Tais we were unable to state a preference. Perhaps in recipes where the lime juice has the starring role, the type of lime used is more important than in more complex recipes.

A Bearss lime tree

However, on sober reflection, and a little scientific method, we came to the conclusion that it is not the type of lime that is most important, it is the ripeness of the fruit. We planted a Bearss lime tree and we were surprised to find that even for the Bearss lime the fruit is yellow when ripe. We found it hard to distinguish between juice from a ripe Key lime and that from a ripe Bearss lime (and they both make a divine Bennett Cocktail). We have to conclude that the fruit available in the stores is inferior because it is picked before it is ripe. In part this may be due to the consumer's expectation that limes should be green but it is also true that green limes travel better. In addition, limes are seasonal. Our trees only bear fruit for about three months during the Northern California winter.