It's that time of year when the little tree in my yard is still yielding fruit, and it seems like almost everyone I know in California is trying to give away lemons. I've already salted a couple of dozen, frozen a pint of juice, candied more peel than I can possibly eat, and I still have more than enough for marmalade and limoncello. I'm not complaining: when the Meyers are gone, which is most of the year, I miss them sorely. Mostly, I miss the scent of lemons. Can I freeze lemon zest? If so, how should I store it?