diff --git a/dumux/material/components/mesitylene.hh b/dumux/material/components/mesitylene.hh
index bfdcce69b172dbff5091eb7e7fb6eb2fb7f04a17..29458d55a95891927135a9b5ca959dcef58831ef 100644
--- a/dumux/material/components/mesitylene.hh
+++ b/dumux/material/components/mesitylene.hh
@@ -143,7 +143,7 @@ public:
         constexpr Scalar p_crit = criticalPressure();
 
         //        Chen method, eq. 7-11.4 (at boiling)
-        constexpr Scalar DH_v_boil = Consts::R * T_crit * Tr1
+        const Scalar DH_v_boil = Consts::R * T_crit * Tr1
         								* (3.978 * Tr1 - 3.958 + 1.555*std::log(p_crit * 1e-5 /*Pa->bar*/ ) )
             							/ (1.07 - Tr1); /* [J/mol] */
 
diff --git a/dumux/material/components/xylene.hh b/dumux/material/components/xylene.hh
index f1db360384e39955ffa7491056a687aeaf90fdea..fb4ac9f41ab3a4c647154dbb3dfd900a0e0991e3 100644
--- a/dumux/material/components/xylene.hh
+++ b/dumux/material/components/xylene.hh
@@ -188,7 +188,7 @@ public:
         constexpr Scalar p_crit = criticalPressure();
 
         //        Chen method, eq. 7-11.4 (at boiling)
-            	constexpr Scalar DH_v_boil = Consts::R * T_crit * Tr1
+            	const Scalar DH_v_boil = Consts::R * T_crit * Tr1
             							* (3.978 * Tr1 - 3.958 + 1.555*std::log(p_crit * 1e-5 /*Pa->bar*/ ) )
             							/ (1.07 - Tr1); /* [J/mol] */