The string trio is a wonderful medium but one for which it is not easy to write. The two middle parts of a quartet, inter alia, provide weight and harmony and are able, in some measure, to "hide" in the general ensemble but in the case of the trio, the only middle part is much more exposed and has to provide a contribution of appreciably greater musical weight and consequence. Perhaps this explains the paucity of literature available in this particular genre (although it gives no clue as to why both Haydn and Beethoven wrote for this combination very early in their careers and before tackling the quartet). However, the five trio examples written by the young Beethoven are real crackers and the Grumiaux/Janzer/Czako ensemble play them to perfection, in my view.
Lighter and more outgoing in character than the succeeding quartets, the trios have a youthful liveliness and a certain ebullience not found to the same degree in the later, perhaps more introverted chamber works. They are superb works in their own right and certainly do not convey the impression that they might be a "dry run" for something on Beethoven's musical horizon. All the trios, save one, are in a major key and the exception soon moves from C minor to the major.
Despite, or perhaps because of, being forty years old, the Philips recording is very good indeed. It might lack the edginess of digital processing (which I don't care for in any event) but the warmth of this production is very much in sympathy with the intimate nature of the work as well as the players, particularly Baron Grumiaux who was always a very polished performer.