diff --git a/bigchaindb/config_utils.py b/bigchaindb/config_utils.py
index 19caef90..df63e7c2 100644
--- a/bigchaindb/config_utils.py
+++ b/bigchaindb/config_utils.py
@@ -113,12 +113,10 @@ def env_config(config):
     return map_leafs(load_from_env, config)
 
 
-def update_types(config):
+def update_types(config, reference, list_sep=':'):
     """Return a new configuration where all the values types
     are aligned with the ones in the default configuration"""
 
-    reference = bigchaindb.config
-
     def _coerce(current, value):
         # Coerce a value to the `current` type.
         try:
@@ -130,7 +128,7 @@ def update_types(config):
             # is a string.
             if isinstance(current, list) and isinstance(value, str):
                 # If so, we use the colon as the separator
-                return value.split(':')
+                return value.split(list_sep)
 
             try:
                 # If we are here, we should try to apply the type
@@ -165,7 +163,7 @@ def dict_config(config):
         update made to ``bigchaindb.config`` will be lost.
     """
     bigchaindb.config = copy.deepcopy(bigchaindb._config)
-    update(bigchaindb.config, update_types(config))
+    update(bigchaindb.config, update_types(config, bigchaindb.config))
     bigchaindb.config['CONFIGURED'] = True
 
 
diff --git a/tests/utils/test_config_utils.py b/tests/utils/test_config_utils.py
index eafcef08..cec7743f 100644
--- a/tests/utils/test_config_utils.py
+++ b/tests/utils/test_config_utils.py
@@ -93,6 +93,27 @@ def test_map_leafs_iterator():
     }
 
 
+def test_update_types():
+    from bigchaindb import config_utils
+
+    raw = {
+        'a_string': 'test',
+        'an_int': '42',
+        'a_float': '3.14',
+        'a_list': 'a:b:c',
+    }
+
+    reference = {
+        'a_string': 'test',
+        'an_int': 42,
+        'a_float': 3.14,
+        'a_list': ['a', 'b', 'c'],
+    }
+
+    result = config_utils.update_types(raw, reference)
+    assert result == reference
+
+
 def test_env_config(monkeypatch):
     monkeypatch.setattr('os.environ', {'BIGCHAINDB_DATABASE_HOST': 'test-host',
                                        'BIGCHAINDB_DATABASE_PORT': 'test-port'})
@@ -143,3 +164,4 @@ def test_autoconfigure_read_both_from_file_and_env(monkeypatch):
         'api_endpoint': 'http://localhost:9984/api/v1',
         'consensus_plugin': 'default',
     }
+