I’ve seen and appreciated soprano Sarah Coburn in a number of operas: “The First Emperor,” “Lucia di Lammermoor” and “Tamerlano” at the Washington National Opera, which crowned her with its Artist of the Year award in 2009. In all of these parts, she showed an able soprano: high notes, low notes, pretty sound. I’ve always wondered, though, why she hasn’t made a more lasting impression on me. After her recital at the National Museum of Women in the Arts on Wednesday night (closing out the fine Shenson Music Concerts for the season), I found an answer: I’m not sure she has a lot to say.

Recitals are not every singer’s cup of tea. You have to perform without a break for a sustained length of time (though Coburn’s scant hour and 10 minutes of music, including intermission and applause, was notably slight). You also have to delve into a different musical repertory from that which you explore on the opera stage, creating drama by yourself, in a more intimate setting.

What Coburn offered, though, was less an opera singer’s recital than that of a talented student, or, with her pale-blue gown and blond coif, a beauty-pageant winner. Earnest and eager, she presented a program that consisted almost entirely of chestnuts: Schubert’s “Rastlose Liebe” and “Gretchen am Spinnrade”; Strauss’s “Morgen,” “Wiegenlied” and “Caecilie”; Rachmaninoff’s “How Beautiful” and “Spring Waters”; and three familiar Spanish songs by Turina and Obradors — all staples of the basic recital repertory. These were framed with three opera arias, with piano accompaniment (courtesy of Anne Breeden). She touched every base, but she didn’t exactly demonstrate a distinctive artistic profile.

She has a perfectly lovely soprano voice. Distinctive is its warm middle register, even extending down to a hint of depth on her low notes, balancing out the more expected golden top ones. If only she employed it with a bit more finesse. She sang softly; she sang loudly; she coquetted in Manon’s gavotte from Massenet’s opera and went all-out in Rosina’s “Una voce poco fa” from Rossini’s “Barber of Seville.” She was strong on the big climaxes, arms extended, head tilted to one side, in ecstatic fortissimos. But the details were weak: rhythms wildly approximate, notes rushed over (notably in Rosina’s roulades).

More damningly, there was little emotional nuance. Gretchen at her spinning wheel sounded less obsessed and driven than merely wistful, like a drawing-room ballad (with Breeden’s accompaniment prettily fluid beneath the voice).

Coburn — who happens to be the youngest daughter of Republican Sen. Tom Coburn — certainly sang solidly and deserves credit for doing her homework. But artistry is more than making pretty sounds or emphatic ones. Another thing opera singers don’t get to have in recital is a stage director; here, one might have helped her figure out not simply what she was singing, but why she was singing it.