Zested lemons often become dry, shriveled, and hard before anyone gets a chance to juice them. What’s the best way to store lemons once their zest has been removed?
The flavorful oil that is found in the outer layer, or zest, of lemon skin protects the fruit from drying out. Once you remove that layer, you remove its primary defense against dehydration.
We stripped the zest (but not the white pith) from four lemons and stored them in the fridge in three different ways: wrapped in plastic, enclosed in a zipper-lock bag, and rubbed with a thin layer of vegetable oil. As a control, we refrigerated a fourth zested lemon that we left alone. To measure moisture loss, we weighed the lemons before and after three weeks of refrigeration. The plastic-wrapped and bagged lemons lost only 2.5 percent and 6 percent of their weight, respectively, yielding plenty of juice. By contrast, the oil-coated lemon suffered a 40 percent loss in weight and was almost indistinguishable from the shriveled control sample, in both its firmness and the miserly portion of bitter juice it released. (Without skin or other protection, the juice in a lemon oxidizes, changing its flavor profile.)
The upshot? If you’re not going to be juicing a zested lemon for a while, wrap it in plastic before refrigerating it.