diff --git a/dune/stuff/functions/expression.hh b/dune/stuff/functions/expression.hh
index 3a007c28a1a5dc14ea2588dc39e0b38de48bfd05..bc8eff923f9c2bf2a6c0fb8f191b0d6a4f8cdf00 100644
--- a/dune/stuff/functions/expression.hh
+++ b/dune/stuff/functions/expression.hh
@@ -216,8 +216,6 @@ public:
       typedef typename Dune::FieldMatrix<std::string, dimRange, dimDomain> JacobianMatrixType;
       const JacobianMatrixType gradient_as_matrix = cfg.get<JacobianMatrixType>("gradient");
       // convert FieldMatrix to std::vector< std::vector < std::string > >
-      assert(gradient_as_matrix.rows >= dimRange);
-      assert(gradient_as_matrix.cols >= dimDomain);
       for (size_t rr = 0; rr < dimRange; ++rr) {
         std::vector<std::string> gradient_expression;
         for (size_t cc = 0; cc < dimDomain; ++cc)