Mexican sour gherkin is a rather new name for a cute little fruit that native people of Mexico and Central America have enjoyed since pre-Columbian times. Melothria scabra, as botanists know it, is often called sandita, “little watermelon,” in Spanish and “mouse melon” in various languages.* These are better names, I think, because although a Mexican sour gherkin is only about an inch long, it looks like a classic watermelon–oval, smooth-skinned, vine-borne, with dark green lengthwise stripes on a pale green background. The taste, though lacking sweetness, is mildly tart, like a watermelon’s, with the aroma of cucumber. As the fruit matures, the stripes fade and the flesh becomes remarkably sour.
Although the Mexican sour gherkin . . . Wait. Can we scrap that awkward name for one that’s easier to say? Although the sandita is in the family Cucurbitaceae, it’s only a distant relative of the watermelon and the cucumber. Some anglo starting calling the sandita a gherkin because you can use it as a gherkin—that is, as a small cucumber. You can pickle it whole.
The compact sandita vine makes a fine ornamental. You can grow it in a pot, though you’ll want the plant at a level at which you can easily hunt under the foliage for the fruits. The leaves are light green, ivy-like, rough to the touch (hence the species name scabra) but not nearly as rough as cucumber leaves, and much less disease-prone, in my experience so far, than are cucumber and melon leaves.
I’ve just pickled my first sanditas. Because I have only one plant, collecting enough fruit to fill a jar took several days. Fortunately, the fruits kept well in the refrigerator, with no sign of deterioration. When I was ready to fill my jar, I didn’t mar the fruit by cutting away the blossom ends; instead I lightly scraped them away with a fingernail.
As the main flavoring for the sanditas I chose tarragon, which is typically used in pickling cornichons. If you dislike licorice-like flavors, you might substitute herbs such as thyme, savory, and bay, or you might use traditional gherkin flavorings such as mustard and dill. I added honey because I thought it would complement the sanditas’ flavor, though the honey slightly darkened the pickling liquid. You might prefer to use white sugar or no sweetening at all. For very sour pickles—to complement, say, pâté or cocktails—use straight vinegar instead of cutting it with water.
4 allspice berries
8 black peppercorns
¼ teaspoon coriander seeds
1 1/3 cups white wine vinegar
2/3 cup water
1½ teaspoon pickling salt
3 tablespoons honey
1 quart sanditas (Melothria scabra)
In a small mortar, lightly crush the allspice, black pepper, and coriander seeds. In a small saucepan, combine the crushed spices with the vinegar, water, salt, and honey. Bring the liquid to a boil, and then let it cool for 5 minutes.
Pack the sanditas into a quart jar. Pour the hot liquid over them, right to the top of the jar (add a little more vinegar if you don’t have enough liquid to fill the jar to the top). Screw on a lid; if it’s metal, put a piece of plastic wrap in between. Let the jar sit at room temperature for at least three days before tasting the pickles. After that they should keep well at room temperature, but you may prefer to eat them chilled.
After three days of pickling the sanditas make a crisp, mildly tart snack; you may find yourself downing them by the dozen. Over time they’ll get more sour and more suitable as an accompaniment to fatty foods.
With my next batch of pickled sanditas, I plan to stab each fruit with a fork before packing the jar. This way the sanditas will have less tendency to float in the jar, and the pickles will be ready sooner.
*Note that this is a different species from Melothria pendula, which grows wild from the southeastern United States to Argentina and bears some of the same popular names. Though many people use the unripe fruits of Melothria pendula in pickles and salads, others consider the whole plant toxic. When the fruit ripens to nearly black, apparently, it becomes an extremely effective remedy for constipation.