Making the transition to summer music can be a bit disorienting. The dress code is different, the repertoire is restricted, the intellectual content and performance quality often compromised. Even the vocabulary is specialized. At the Mostly Mozart Festival, “A Little Night Music” is the name of a series of recitals at the Kaplan Penthouse, while “Eine kleine Nachtmusik” is the piece featured in the opening concert of the opening week of the festival (bearing in mind the rather confusing phenomenon that “opening night” actually occurred in the middle of last week).

This arcane terminology cries out for an experienced guide, and so it was fortunate that music educator Rob Kapilow hosted Monday’s evening at the Walter Reade Theater, titled “What Makes It Great?” Everything about Mr. Kapilow bespeaks youthful enthusiasm, and both his haircut and cracking voice belie the fact that he studied with Nadia Boulanger. His approach is extremely hands-on and works well for the particular crowd, many with children in tow, who know his educative style.

Appearing at Mostly Mozart for the first time, Mr. Kapilow adopted a teaching technique that was simple yet complex, mirroring “Eine kleine Nachtmusik” itself. For about one hour, he explicated various passages from the tossed-off serenade, illustrating his points with piano figures and snippets of the finished product proclaimed by the Jupiter String Quartet.

His basic premise was that Mozart surprises at every turn. Thus we were all treated to a basic lesson in harmony, rhythm, and variation technique, particularly as it applies to post-Baroque ornamentation. The audience was asked to participate by singing and clapping and, as Mr. K pointed out, was able to stop as a unit much better than many of our local professional ensembles.

At the national spelling bee this year, the winning word was appoggiatura. It was a delight to hear Mr. Kapilow extol the praises of this yearning type of figure and define it much more satisfactorily than the dictionary or the sportscasters ever could. In just a few moments, he turned this rather naive crowd into a lean, mean music machine, able to spot the difference between a trill and an appoggiatura and know instinctively why one was more appropriate than the other as an individual ornamental device.

Mr. Kapilow parses Mozart much the way that Robert Levin does, but without the scholarship. Both of these good communicators recompose Mozartian passages in order to illustrate the more conventional, and therefore less creative, alternatives to Wolfgang’s exuberant strokes of genius. If I had a quibble with Mr. Kapilow’s talk, it was his often repeated thesis that reading scholars is boring and ultimately irrelevant. He appeared to be trying just a tad too hard for the audience members to like him, reveling in the projection that he was “just a regular guy.” I found this approach quite condescending.

What he did magically create, and in a short period of time, was a sense in the audience of enthusiastic anticipation, so that when certain passages would appear in the actual performance of the piece, they were familiar old friends. Ironically, those who learned their lessons well must have been disappointed in the final Jupiter rendition.

The quartet is a youthful one and probably will grow with time. Unfortunately, they have a very thin tone, so the painstakingly lovely passages that we had just studied before intermission were not intoned with a transcendental sense of beauty and power. The Jupiter approach to the work as a whole was certainly legitimate, emphasizing the homogeneity of tempi common in Mozart’s time, but the Andante and the Menuetto were a little too fast for these tired ears.

After one has listened for 10 minutes to an explication of just seven seconds of music, it is natural to expect a fine realization of that music in actual, real time performance. This was often not the case this night. The final Rondo was a witch’s brew of wrong notes and sloppy entrances. In their defense, perhaps the young artists could no longer treat the individual phrases as parts of the totality once they had been recruited to play them for us as naked, bleeding chunks.

Zubin Mehta loves to tell the story of hearing a terrible performance of “Eine kleine” in India. Upbraiding the conductor after the show, Mr. Mehta was taken aback when the local maestro’s response was “you should have heard them six months ago!” The love of great music is a process, a lifelong quest in pursuit of the ideal. In an America where most schoolchildren think of Beethoven not as a composer but as a Saint Bernard, these types of educative evenings are essential. The journey, not the arrival, is what matters.