diff --git a/nomad/metainfo/metainfo.py b/nomad/metainfo/metainfo.py
index 59e554b9a31e582c3d1dd908e7588032f10f45b3..4523faddd567fa0c0e425a6130c6ba9c6e224a7f 100644
--- a/nomad/metainfo/metainfo.py
+++ b/nomad/metainfo/metainfo.py
@@ -392,20 +392,11 @@ class _Unit(DataType):
 
         return value.__str__()
 
-        # The delta prefixes are not serialized: only implicit deltas are
-        # allowed currently.
-        # return reduce(lambda a, b: a.replace(b, ''), _delta_symbols, value)
-
     def deserialize(self, section, quantity_def: Quantity, value):
         check_unit(value)
-
-        # The serialized version has the deltas always in correct locations, so
-        # we skip the automatic delta conversion. This way users can also choose
-        # to not use delta units with ureg.parse_units('celsius/hr',
-        # as_delta=False)
-        value = units.parse_units(value, as_delta=False)
-
+        value = units.parse_units(value)
         check_dimensionality(quantity_def, value)
+
         return value
 
 
diff --git a/tests/metainfo/test_metainfo.py b/tests/metainfo/test_metainfo.py
index f4702c2528b2183573450facefd2856b47e71055..cb7d75da73e70680de7e7a9e29f3b125f62a7896 100644
--- a/tests/metainfo/test_metainfo.py
+++ b/tests/metainfo/test_metainfo.py
@@ -215,58 +215,71 @@ class TestM2:
         assert System.lattice_vectors.unit is not None
 
     @pytest.mark.parametrize(
-        'unit, serialization',
+        'unit, serialized, deserialized',
         [
             pytest.param(
                 'delta_degC',
                 'delta_degree_Celsius',
+                'delta_degree_Celsius',
                 id='explicit delta full, non-multiplicative, string',
             ),
             pytest.param(
                 'ΔdegC',
                 'delta_degree_Celsius',
+                'delta_degree_Celsius',
                 id='explicit delta short, non-multiplicative, string',
             ),
             pytest.param(
                 'delta_degC / hr',
                 'delta_degree_Celsius / hour',
+                'delta_degree_Celsius / hour',
                 id='explicit delta full, multiplicative, string',
             ),
             pytest.param(
                 'ΔdegC / hr',
                 'delta_degree_Celsius / hour',
+                'delta_degree_Celsius / hour',
                 id='explicit delta short, multiplicative, string',
             ),
             pytest.param(
                 ureg.delta_degC / ureg.hour,
                 'delta_degree_Celsius / hour',
+                'delta_degree_Celsius / hour',
                 id='explicit delta, multiplicative, objects',
             ),
             pytest.param(
                 'degC / hr',
                 'delta_degree_Celsius / hour',
+                'delta_degree_Celsius / hour',
                 id='implicit delta, multiplicative, string',
             ),
-            pytest.param('degC', 'degree_Celsius', id='no delta, non-multiplicative'),
+            pytest.param(
+                'degC',
+                'degree_Celsius',
+                'degree_Celsius',
+                id='no delta, non-multiplicative',
+            ),
             pytest.param(
                 ureg.parse_units('degC / hr', as_delta=False),
                 'degree_Celsius / hour',
-                id='no delta, multiplicative, string',
+                'delta_degree_Celsius / hour',
+                id='non-delta units ignored in deserialization 1',
             ),
             pytest.param(
                 ureg.degC / ureg.hour,
                 'degree_Celsius / hour',
-                id='no delta, multiplicative, objects',
+                'delta_degree_Celsius / hour',
+                id='non-delta units ignored in deserialization 2',
             ),
         ],
     )
-    def test_unit_delta(self, unit, serialization):
+    def test_unit_delta(self, unit, serialized, deserialized):
         quantity = Quantity(type=np.dtype(np.float64), unit=unit)
-        serialized = quantity.m_to_dict()
-        deserialized = quantity.m_from_dict(serialized)
+        serialized_dict = quantity.m_to_dict()
+        deserialized_obj = quantity.m_from_dict(serialized_dict)
 
-        assert serialized['unit'] == serialization
-        assert str(deserialized.unit) == str(quantity.unit)
+        assert serialized_dict['unit'] == serialized
+        assert str(deserialized_obj.unit) == deserialized
 
     @pytest.mark.parametrize(
         'dtype', [pytest.param(np.longlong), pytest.param(np.ulonglong)]