There is one other way in which a promise can be made binding without consideration: it can be put into a document called a deed. An agreement by deed is often described as a formal contract or a contract of specialty; other types of contract are usually called simple contracts.
The procedure for making an agreement by deed usually involves signing s formal document in the presence of a witness. Deeds are typically used to give binding legal effect to what might otherwise be a gratuitous gift, which would be unenforceable for lack of consideration.