[H]ere’s where it gets tricky: that orange and that lemon. Turns out you have to carefully peel off the zest which is the thinnest uppermost part of the peel and DON’T WHATEVER YOU DO GET A SPECK OF THE PITH, THAT NASTY WHITE STUFF, WITH IT. Okay, my cookbook author didn’t exactly write those instructions that way or in capital letters but I sensed the urgency. She didn’t explain exactly what would happen if I inadvertently allowed pith to contaminate my zest. Bitterness? A dangerous chemical reaction? A meth lab like explosion? Note to cookbook writers: We laypeople like to know these things.
Much to everyone’s relief, the very first commenter explained it all:
You don’t want the pith because it is bitter and can make reduced dishes like jellies and jams especially bitter.
Direct enough. Even, as Lisa noted, pithy.
Me, I consider myself fortunate that I knew what “pith” and “zest” were.