diff --git a/wagtail/wagtailsearch/backends/__init__.py b/wagtail/wagtailsearch/backends/__init__.py
index 36e7fe8d11..cc0b3e6167 100644
--- a/wagtail/wagtailsearch/backends/__init__.py
+++ b/wagtail/wagtailsearch/backends/__init__.py
@@ -15,6 +15,17 @@ class InvalidSearchBackendError(ImproperlyConfigured):
     pass
 
 
+def get_search_backend_config():
+    search_backends = getattr(settings, 'WAGTAILSEARCH_BACKENDS', {})
+
+    # Make sure the default backend is always defined
+    search_backends.setdefault('default', {
+        'BACKEND': 'wagtail.wagtailsearch.backends.db',
+    })
+
+    return search_backends
+
+
 def import_backend(dotted_path):
     """
     Theres two formats for the dotted_path.
@@ -39,19 +50,12 @@ def import_backend(dotted_path):
 
 
 def get_search_backend(backend='default', **kwargs):
-    # Get configuration
-    default_conf = {
-        'default': {
-            'BACKEND': 'wagtail.wagtailsearch.backends.db',
-        },
-    }
-    WAGTAILSEARCH_BACKENDS = getattr(
-        settings, 'WAGTAILSEARCH_BACKENDS', default_conf)
+    search_backends = get_search_backend_config()
 
     # Try to find the backend
     try:
         # Try to get the WAGTAILSEARCH_BACKENDS entry for the given backend name first
-        conf = WAGTAILSEARCH_BACKENDS[backend]
+        conf = search_backends[backend]
     except KeyError:
         try:
             # Trying to import the given backend, in case it's a dotted path
@@ -92,14 +96,12 @@ def _backend_requires_auto_update(backend_name, params):
 
 
 def get_search_backends_with_name(with_auto_update=False):
-    if hasattr(settings, 'WAGTAILSEARCH_BACKENDS'):
-        for backend, params in settings.WAGTAILSEARCH_BACKENDS.items():
-            if with_auto_update and _backend_requires_auto_update(backend, params) is False:
-                continue
+    search_backends = get_search_backend_config()
+    for backend, params in search_backends.items():
+        if with_auto_update and _backend_requires_auto_update(backend, params) is False:
+            continue
 
-            yield backend, get_search_backend(backend)
-    else:
-        yield 'default', get_search_backend('default')
+        yield backend, get_search_backend(backend)
 
 
 def get_search_backends(with_auto_update=False):
diff --git a/wagtail/wagtailsearch/tests/test_backends.py b/wagtail/wagtailsearch/tests/test_backends.py
index bd168c7404..a115e8e626 100644
--- a/wagtail/wagtailsearch/tests/test_backends.py
+++ b/wagtail/wagtailsearch/tests/test_backends.py
@@ -186,6 +186,15 @@ class TestBackendLoader(TestCase):
         self.assertEqual(len(backends), 1)
         self.assertIsInstance(backends[0], DBSearch)
 
+    @override_settings(
+        WAGTAILSEARCH_BACKENDS={}
+    )
+    def test_get_search_backends_with_no_default_defined(self):
+        backends = list(get_search_backends())
+
+        self.assertEqual(len(backends), 1)
+        self.assertIsInstance(backends[0], DBSearch)
+
     @override_settings(
         WAGTAILSEARCH_BACKENDS={
             'default': {