diff --git a/config/common.conf b/config/common.conf
index c2bdb28..1f8165d 100644
--- a/config/common.conf
+++ b/config/common.conf
@@ -19,6 +19,10 @@ DISTDIR="/usr/portage/distfiles"
 # timestamp in output files. This option can be overridden by using -D option.
 TARBALLDATE="%Y%m"
 
+# This option specifies a compression algorithm that will be used to produce any tarball
+# images, including stages as well as Portage snapshots. Actually supported: bz2, gz, xz.
+TARBALLFORMAT="xz"
+
 # A time designation representing the time in seconds that you allow the connection to
 # the server to take. This only limits the connection phase, once it has connected this
 # option is of no more use. Setting a timeout to 0 disables it altogether. Unless you