diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -99,6 +99,17 @@
   congratulations :)
 ```
 
+Note: it is possible to set the `JAVA_HOME` environment variable to specify the
+version of the JVM to be used by Cassandra. For example, at the time of writing
+this, Cassandra does not support java 14, so one may want to use for example
+java 11:
+
+```
+(swh) :~/swh-storage$ export JAVA_HOME=/usr/lib/jvm/java-14-openjdk-amd64/bin/java
+(swh) :~/swh-storage$ tox
+[...]
+```
+
 ## Development
 
 The storage server can be locally started. It requires a configuration file and
diff --git a/swh/storage/tests/test_cassandra.py b/swh/storage/tests/test_cassandra.py
--- a/swh/storage/tests/test_cassandra.py
+++ b/swh/storage/tests/test_cassandra.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2018-2020  The Software Heritage developers
+# Copyright (C) 2018-2021  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
@@ -102,6 +102,14 @@
         stdout = stderr = subprocess.DEVNULL
 
     cassandra_bin = os.environ.get("SWH_CASSANDRA_BIN", "/usr/sbin/cassandra")
+    env = {
+        "MAX_HEAP_SIZE": "300M",
+        "HEAP_NEWSIZE": "50M",
+        "JVM_OPTS": "-Xlog:gc=error:file=%s/gc.log" % cassandra_log,
+    }
+    if "JAVA_HOME" in os.environ:
+        env["JAVA_HOME"] = os.environ["JAVA_HOME"]
+
     proc = subprocess.Popen(
         [
             cassandra_bin,
@@ -111,11 +119,7 @@
             "-Dcassandra-foreground=yes",
         ],
         start_new_session=True,
-        env={
-            "MAX_HEAP_SIZE": "300M",
-            "HEAP_NEWSIZE": "50M",
-            "JVM_OPTS": "-Xlog:gc=error:file=%s/gc.log" % cassandra_log,
-        },
+        env=env,
         stdout=stdout,
         stderr=stderr,
     )
diff --git a/tox.ini b/tox.ini
--- a/tox.ini
+++ b/tox.ini
@@ -10,6 +10,7 @@
 passenv =
   SWH_CASSANDRA_BIN
   SWH_CASSANDRA_LOG
+  JAVA_HOME
 commands =
   pytest \
     !slow: --hypothesis-profile=fast \