diff --git a/astroquery/eso/core.py b/astroquery/eso/core.py
index d63a5808d7..e9f9a1b1e1 100644
--- a/astroquery/eso/core.py
+++ b/astroquery/eso/core.py
@@ -461,7 +461,7 @@ def retrieve_data(self, datasets, cache=True):
 
         Returns
         -------
-        files : list of strings
+        files : list of strings or string
             List of files that have been locally downloaded from the archive.
 
         Examples
@@ -475,7 +475,10 @@ def retrieve_data(self, datasets, cache=True):
         files = []
 
         if isinstance(datasets, six.string_types):
+            return_list = False
             datasets = [datasets]
+        else:
+            return_list = True
         if not isinstance(datasets, (list, tuple, np.ndarray)):
             raise TypeError("Datasets must be given as a list of strings.")
 
@@ -546,7 +549,10 @@ def retrieve_data(self, datasets, cache=True):
                 fileLink = "http://dataportal.eso.org/dataPortal"+fileId.attrs['value'].split()[1]
                 filename = self._request("GET", fileLink, save=True)
                 files.append(system_tools.gunzip(filename))
+        self._session.redirect_cache.clear() # EMpty the redirect cache of this request session
         log.info("Done!")
+        if (not return_list) and (len(files)==1):
+            files = files[0]
         return files
 
     def verify_data_exists(self, dataset):
diff --git a/astroquery/eso/tests/test_eso_remote.py b/astroquery/eso/tests/test_eso_remote.py
index 85504bfd68..5613a33baa 100644
--- a/astroquery/eso/tests/test_eso_remote.py
+++ b/astroquery/eso/tests/test_eso_remote.py
@@ -112,3 +112,10 @@ def test_retrieve_data(self):
         result = eso.retrieve_data("MIDI.2014-07-25T02:03:11.561")
         assert len(result)>0
         assert "MIDI.2014-07-25T02:03:11.561" in result[0]
+
+    @pytest.mark.skipif('not Eso.USERNAME')
+    def test_retrieve_data_twice(self):
+        eso = Eso()
+        eso.login()
+        result1 = eso.retrieve_data("MIDI.2014-07-25T02:03:11.561")
+        result2 = eso.retrieve_data("AMBER.2006-03-14T07:40:19.830")
diff --git a/astroquery/query.py b/astroquery/query.py
index 6c93f30c8f..bd0d8fe7b1 100644
--- a/astroquery/query.py
+++ b/astroquery/query.py
@@ -18,6 +18,7 @@
 
 
 def to_cache(response, cache_file):
+    log.debug("Caching data to {0}".format(cache_file))
     with open(cache_file, "wb") as f:
         pickle.dump(response, f)
 
@@ -71,11 +72,9 @@ def hash(self):
 
     def request_file(self, cache_location):
         fn = os.path.join(cache_location, self.hash() + ".pickle")
-        log.debug("Request file is {0}".format(fn))
         return fn
 
     def from_cache(self, cache_location):
-        log.debug("Retrieving data from {0}".format(cache_location))
         request_file = self.request_file(cache_location)
         try:
             with open(request_file, "rb") as f:
@@ -84,6 +83,8 @@ def from_cache(self, cache_location):
                 response = None
         except:
             response = None
+        if response:
+            log.debug("Retrieving data from {0}".format(request_file))
         return response
 
 
@@ -95,7 +96,7 @@ class BaseQuery(object):
     """
 
     def __init__(self):
-        self.__session = requests.session()
+        self._session = requests.session()
         self.cache_location = os.path.join(paths.get_cache_dir(), 'astroquery',
                                            self.__class__.__name__.split("Class")[0])
         if not os.path.exists(self.cache_location):
@@ -157,12 +158,12 @@ def _request(self, method, url, params=None, data=None, headers=None,
             if ((self.cache_location is None) or (not self._cache_active) or
                 (not cache)):
                 with suspend_cache(self):
-                    response = query.request(self.__session, stream=stream,
+                    response = query.request(self._session, stream=stream,
                                              auth=auth)
             else:
                 response = query.from_cache(self.cache_location)
                 if not response:
-                    response = query.request(self.__session,
+                    response = query.request(self._session,
                                              self.cache_location,
                                              stream=stream,
                                              auth=auth)
@@ -172,9 +173,9 @@ def _request(self, method, url, params=None, data=None, headers=None,
     def _download_file(self, url, local_filepath, timeout=None, auth=None):
         """
         Download a file.  Resembles `astropy.utils.data.download_file` but uses
-        the local ``__session``
+        the local ``_session``
         """
-        response = self.__session.get(url, timeout=timeout, stream=True,
+        response = self._session.get(url, timeout=timeout, stream=True,
                                       auth=auth)
         if 'content-length' in response.headers:
             length = int(response.headers['content-length'])