To European standards he was not, but to American standards maybe. One thing is for sure: though Beethoven surely had a dark complexion, he didn't have a black or brown skin, nor negroid features. On the contrary. His portraits show a typical European face and so does a portrait of one his brothers and two portraits of his nephew Karl. His ancestors were partly Flemish (the Beethovens), partly German (the Keverichs). At first sight there's not the slightest trace of a proof for his "blackness". Yet we cannot exclude beyond any doubt that he had some drops "black" blood in his veins. During the so-called 80-year-war (1568-1648) Flanders and the southern part of the Netherlands were occupied by the Spanish and a part of the Spanish army was "Moorish", as they called it in those days, which means from Northern Africa. So it's not completely impossible that one of those soldiers had been the cause of some African genes in the Beethoven family.
Schmidt-Gorg, Joseph. Beethoven. Die Geschichte seiner Familie. (Bonn, 1964).
Weffer, Herbert. Nochmals Beethoven-Verwandtschaft. In: Die Laterne. Mitteilungsblatt der Westdeutschen Gesellschaft fur Familienkunde. (1969).
Schmidt-Gorg, Joseph. Des Backermeister Gottfried Fischer Aufzeichnungen uber Beethovens Jugend. (Bonn, 1971).
Mann, Werner. Beethoven in Bonn. Seine Familie, seine Lehrer und Freunde. (Bonn, omstreeks 1982).
Raab, Armin. Beethovens Mutter - Legenden und Tatsachen. In: Bonner Beethoven-Studien. (Bonn, 1999).
Wetzstein, Margot. Familie Beethoven in Kurfurstlichen Bonn. Neuauflage nach den Aufzeichnungen des Bonner Backermeisters Fischer. (Bonn, 2006).