  We discuss how inflation can emerge from a four-fermion interaction induced
by torsion. Inflation can arise from coupling torsion to Standard Model
fermions, without any need of introducing new scalar particles beyond the
Standard Model. Within this picture, the inflaton field can be a composite
field of the SM-particles and arises from a Nambu-Jona-Lasinio mechanism in
curved space-time, non-minimally coupled with the Ricci scalar. The model we
specify predicts small value of the r-parameter, namely $r\sim 10^{-4} \div
10^{-2}$, which nonetheless would be detectable by the next generation of
experiments, including BICEP 3 and the AliCPT projects.
