How to peel a grapefruit

Robert L. Wolke writes Food 101 for the Washington Post's Food section: in it, he answers all manner of arcane questions in a sprightly, informative fashion.

Wednesday's Q&A was about why it's so much more difficult to peel a grapefruit than an orange, and how the pros do it.

Here's the citrus truth, the whole segment and nothing but the fruit, so help me God.

Q. Although I can generally peel oranges quite easily, I have found it impossible to peel a grapefruit by hand without splitting or tearing the fruit. So how do they produce the perfect, skinless segments found in cans?

A. By one method you can adopt at home, and another that you probably cannot.

In between the colored peel of a citrus fruit and the juicy inner segments is a layer of spongy white pith called the albedo.

In many oranges, and especially in tangerines, the albedo and the peel aren't cemented to each other as tightly as they are in grapefruit.

There are several methods for separating the two layers.

At home, you can immerse the unpeeled fruit for a few minutes in hot or boiling water.

The heat will expand the peel and puff up the gas-filled albedo.

Then, after cutting off a slice from one end to start the peeling, you can separate the two layers rather easily.

In one widely used commercial method, the rinds are first scored by machine, after which the fruits are immersed completely in a solution of an albedo-digesting enzyme (pectinase) and subjected to a vacuum.

The vacuum sucks the gas out of the albedo, and when air is let back in, the enzyme solution runs into the evacuated pores, where it attacks and loosens the albedo sufficiently to allow it to be removed by hand.