This invention relates to a binder composition comprising condensed tannin and furfuryl alcohol. The composition can be used to prepare foundry mixes. The foundry mixes are prepared by mixing the composition with an acid or salt of an acid. The foundry mixes are then shaped into molds or cores and cured by heating or by the no-bake process with stronger acid curing catalysts. The molds and cores are used in casting metal articles.