diff --git a/site.mk b/site.mk
index a751c30..221c2c1 100644
--- a/site.mk
+++ b/site.mk
@@ -15,7 +15,7 @@ GLUON_SITE_PACKAGES := \
 	firewall \
 	haveged
 
-DEFAULT_GLUON_RELEASE := 0.3.101-nightly$(shell date '+%Y%m%d'),
+DEFAULT_GLUON_RELEASE := 0.3.101-nightly$(shell date '+%Y%m%d')
 
 # Allow overriding the release number from the command line
 GLUON_RELEASE ?= $(DEFAULT_GLUON_RELEASE)