diff --git a/CMakeLists.txt b/CMakeLists.txt
index e2f779731..dbebb2cde 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -33,18 +33,6 @@ message(STATUS "${projectPrefix}BUILD_MODULES: ${${projectPrefix}BUILD_MODULES}"
 option(${projectPrefix}BUILD_LA "Build code depending on the linear algebra library" ON)
 message(STATUS "${projectPrefix}BUILD_LA: ${${projectPrefix}BUILD_LA}")
 
-if(${projectPrefix}BUILD_MODULES)
-    if(CMAKE_VERSION VERSION_LESS "3.27.0")
-        set(CMAKE_EXPERIMENTAL_CXX_MODULE_CMAKE_API "2182bf5c-ef0d-489a-91da-49dbc3090d2a")
-    elseif(CMAKE_VERSION VERSION_LESS "3.28.0")
-        set(CMAKE_EXPERIMENTAL_CXX_MODULE_CMAKE_API "aa1f7df0-828a-4fcd-9afc-2dc80491aca7")
-    elseif(NOT (DEFINED CMAKE_EXPERIMENTAL_CXX_MODULE_CMAKE_API))
-        message(FATAL_ERROR
-                    "${projectPrefix}BUILD_MODULES is set, but CMAKE_EXPERIMENTAL_CXX_MODULE_CMAKE_API is undefined."
-        )
-    endif()
-endif()
-
 # make sure that the file is being used as an entry point
 include(modern_project_structure)
 ensure_entry_point()
diff --git a/conanfile.py b/conanfile.py
index 957bfaa75..f54614fea 100644
--- a/conanfile.py
+++ b/conanfile.py
@@ -147,6 +147,8 @@ def generate(self):
         tc.variables["MP_UNITS_BUILD_MODULES"] = self._build_modules
         tc.variables["MP_UNITS_BUILD_LA"] = self._build_all and not self._skip_la
         tc.variables["MP_UNITS_USE_LIBFMT"] = self._use_libfmt
+        if self._build_modules:
+            tc.variables["CMAKE_EXPERIMENTAL_CXX_MODULE_CMAKE_API"] = "aa1f7df0-828a-4fcd-9afc-2dc80491aca7"
         tc.generate()
         deps = CMakeDeps(self)
         deps.generate()