Composite volcanoes, also known as stratovolcanoes, typically erupt andesite lava.

Here's why:

* Andesite is an intermediate type of lava with a silica content between that of basalt (mafic) and rhyolite (felsic).

* Intermediate silica content leads to a higher viscosity, meaning it flows more slowly and can build up steep, cone-shaped structures.

* Explosive eruptions: This viscosity also makes andesite prone to explosive eruptions, a hallmark of composite volcanoes.

While andesite is the most common lava type in composite volcanoes, other types like dacite and even rhyolite can also be present, depending on the specific composition of the magma source.