diff --git a/common/python/nomadcore/simple_parser.py b/common/python/nomadcore/simple_parser.py
index 8ab4885a343d301fb7dbd8b8dbaf5a0e544ce7e9..91175134038c5f23109fa0b9deef35435f34d50a 100644
--- a/common/python/nomadcore/simple_parser.py
+++ b/common/python/nomadcore/simple_parser.py
@@ -548,7 +548,11 @@ class CompiledMatcher(object):
     def addStrValue(self, backend, metaNameWithUnits, strValue):
         """adds a string value with unit conversions (only for the groups in start and endRe)"""
         metaName = metaNameWithUnits.split("__")[0]
-        value = backend.convertScalarStringValue(metaName, strValue)
+        transformer = self.transformers.get(metaName, None)
+        if transformer:
+            value = transformer(strValue)
+        else:
+            value = backend.convertScalarStringValue(metaName, strValue)
         self.addValue(backend, metaName, value)
 
     def addValue(self, backend, metaName, value):