diff --git a/src/scheme/AcousticSolver.hpp b/src/scheme/AcousticSolver.hpp
index 3bc6269eea2c7d74b4fee36d13e6da83db19fafc..a44fea85ecf5891428f186da174aa8c02d20ccef 100644
--- a/src/scheme/AcousticSolver.hpp
+++ b/src/scheme/AcousticSolver.hpp
@@ -322,7 +322,6 @@ class AcousticSolver
 
     CellValue<double>& ej = unknowns.ej();
     CellValue<double>& pj = unknowns.pj();
-    CellValue<double>& gammaj = unknowns.gammaj();
     CellValue<double>& cj = unknowns.cj();
 
     const CellValue<const Rd>& xj = m_mesh_data.xj();