Sepideh sent me a cryptic email: “Do you know about sweet lemons?” was all she wrote. I replied that I thought, based on a quick glance at a sweet lemon in the neighborhood market, that it was like a Meyer’s lemon. “Not so fast, my friend”, was her response.
Crap… dang… #MN$#$%!!! I hate not knowing the answer, especially when it comes to food. So, the following summary is the result of my research to correct a lamentable lack of knowledge on sweet lemons (limes). I also did not want you to feel the same awkwardness, and so if you are ever asked, at least you’ll have a better response. I added sweet limes to the mix, because, while sweet lemons and sweet limes are two different fruit, they are frequently mixed up, as evidenced by the sign pictured above. Part of the problem is that some languages do not distinguish between lemons and limes, leading to confusion on the part of the unsuspecting. According to Dr. Bahman Ebdaie of the University of California, Riverside, sweet limes are called sweet lemons in Farsi. The tricky part is that they are really two different fruits, and I still struggle to explain the differences, but I can tell you that now is the season for sweet lemons/limes, I am finding this yummy bounty in my neighborhood markets and have been not skimping on my Vitamin C.
So here is a bit of what I learned:
First, I have to say, Harold McGee let me down; nary a mention of sweet lemons or sweet limes in either edition of his book, On Food and Cooking. I approached my friends, one of whom forwarded my query to David Karp, who kindly responded with a very generous, detailed answer.
“You’re right that the names “sweet lime” and “sweet lemon” are popularly used interchangeably; scientifically, the truth is more complex.
True botanical sweet lemons are acidless mutations of the common sour lemon, Citrus limon are rare in the United States, but can be found in parts of the Middle East and North Africa. They look like the common ‘Eureka’ and ‘Lisbon’ lemons, the sour lemons of commerce in the United States – elongated, with a nipple. There is a low-acid variety called ‘Dorshapo‘ after the plant explorers, Dorsett, Shamel and Popenoe, who introduced it from Brazil in 1914; it was once present in the United States, but it is unclear whether it [remains]. There is a true partly sweet lemon variety called ‘Faris’ at the Citrus Variety Collection at the University of California at Riverside; but it is genetically unstable, in that fruits on some limbs are “sweet” (actually insipid), some are sour, and some are intermediate. By the way, recent molecular marker studies indicate that lemons may have originated from an ancient hybrid (or hybrids) of sour orange (seed) and citron (pollen).
Sweet limes, far more common than true botanical sweet lemons, and are from another species, Citrus limettioides. They are not just acidless versions of sour limes (the small-fruited Mexican or Key lime, Citrus aurantifolia; or the large-fruited Tahitian, Persian or Bearss limes, Citrus latifolia). They are believed to have arisen from a natural hybrid of either sweet orange (C. sinensis) or small-fruited acid lime (C. aurantifolia) x citron (C. medica) – which could be the same combination as large-fruited acid limes, but probably different genotypes. They are round, medium in size, with thin skin, and an insipid, slightly soapy flavor. Here’s a sweet lime.
There is another species, Citrus limetta, which appears to be closely related to Citrus limettioides; it includes the limettas, which are also often called sweet lemons, though they are really closer to the sweet limes.
There is also the Palestine Sweet Lime (Citrus limettioides or Citrus lumia Risso et Poit.). The Palestine sweet lime or limetta is a hybrid. It is not known where or how the sweet lime originated. It is thought to be a hybrid between a Mexican lime and a sweet lemon or sweet citron, and believed to be native to India. It is primarily grown in central and northern India, northern Vietnam, Egypt and the Mediterranean coast. It arrived to the U.S. from Saharanpur, India, in 1904, and has a small cultivation in California.
How They Taste
If you caught David’s description of the limes being slightly insipid, its because they have a very low acidity which makes them an acquired taste. Compared to the standard lime which has about 6% acidy and oranges which hover at 1%, sweet limes/lemons have less than 0.1%. Its not that they are necessarily sweet, its that they are devoid of acid to make them tart.
Ideas on How to Eat
In the West Indies and Central America, it is eaten by cutting off the stem end, piercing the core with a knof and sucking out the juice. The fruit is eaten fresh in India, cooked or preserved. It is called limettier doux in French; lima dulcein Spanish; mitha limbu, mitha nimbu, or mitha nebu, in India (mitha meaning “sweet”); quit giay in Vietnam; limun helou, or succari in Egypt; laymun-helo in Syria and Palestine.
From My Persian Kitchen – a few ideas on using sweet limes