diff --git a/aiocache/backends/redis.py b/aiocache/backends/redis.py
index e3b5d99f..350da968 100644
--- a/aiocache/backends/redis.py
+++ b/aiocache/backends/redis.py
@@ -41,6 +41,14 @@ def __init__(
         **kwargs,
     ):
         super().__init__(**kwargs)
+
+        # NOTE: decoding can't be controlled on API level after switching to
+        # redis, we need to disable decoding on global/connection level
+        # (decode_responses=False), because some of the values are saved as
+        # bytes directly, like pickle serialized values, which may raise an
+        # exception when decoded with 'utf-8'.
+        if client.connection_pool.connection_kwargs['decode_responses']:
+            raise ValueError("redis client must be constructed with decode_responses set to False")
         self.client = client
 
     async def _get(self, key, encoding="utf-8", _conn=None):
diff --git a/aiocache/factory.py b/aiocache/factory.py
index 2dca8a82..14cd8573 100644
--- a/aiocache/factory.py
+++ b/aiocache/factory.py
@@ -1,3 +1,4 @@
+import copy
 import logging
 import urllib
 from copy import deepcopy
@@ -20,6 +21,7 @@ def _class_from_string(class_path):
 
 
 def _create_cache(cache, serializer=None, plugins=None, **kwargs):
+    kwargs = copy.deepcopy(kwargs)
     if serializer is not None:
         cls = serializer.pop("class")
         cls = _class_from_string(cls) if isinstance(cls, str) else cls
diff --git a/tests/conftest.py b/tests/conftest.py
index e7302075..874b163e 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -7,16 +7,20 @@ def max_conns():
     return None
 
 
+@pytest.fixture()
+def decode_responses():
+    return False
+
+
 @pytest.fixture
-async def redis_client(max_conns):
-    r = redis.Redis(
+async def redis_client(max_conns, decode_responses):
+    async with redis.Redis(
         host="127.0.0.1",
         port=6379,
         db=0,
         password=None,
-        decode_responses=False,
+        decode_responses=decode_responses,
         socket_connect_timeout=None,
         max_connections=max_conns
-    )
-    yield r
-    await r.close()
+    ) as r:
+        yield r
diff --git a/tests/ut/backends/test_memcached.py b/tests/ut/backends/test_memcached.py
index e774351c..f0de04cb 100644
--- a/tests/ut/backends/test_memcached.py
+++ b/tests/ut/backends/test_memcached.py
@@ -38,7 +38,7 @@ def test_setup(self):
 
     def test_setup_override(self):
         with patch.object(aiomcache, "Client", autospec=True) as aiomcache_client:
-            memcached = MemcachedBackend(endpoint="127.0.0.2", port=2, pool_size=10)
+            memcached = MemcachedBackend(host="127.0.0.2", port=2, pool_size=10)
 
             aiomcache_client.assert_called_with("127.0.0.2", 2, pool_size=10)
 
diff --git a/tests/ut/backends/test_redis.py b/tests/ut/backends/test_redis.py
index 1208e3e6..2efb2e7c 100644
--- a/tests/ut/backends/test_redis.py
+++ b/tests/ut/backends/test_redis.py
@@ -30,6 +30,15 @@ def redis(redis_client):
 
 class TestRedisBackend:
 
+    @pytest.mark.parametrize('decode_responses', [True])
+    async def test_redis_backend_requires_client_decode_responses(self, redis_client):
+        with pytest.raises(ValueError) as ve:
+            RedisBackend(client=redis_client)
+
+        assert str(ve.value) == (
+            "redis client must be constructed with decode_responses set to False"
+        )
+
     async def test_get(self, redis):
         redis.client.get.return_value = b"value"
         assert await redis._get(Keys.KEY) == "value"