diff --git a/install/scripts/install_ocaml.sh b/install/scripts/install_ocaml.sh
index e56a825..5ce0d8c 100755
--- a/install/scripts/install_ocaml.sh
+++ b/install/scripts/install_ocaml.sh
@@ -54,9 +54,7 @@ set -u
 cd Downloads 
 chmod +x opam_installer.sh
 rm --force ${QMCCHEM_PATH}/bin/opam
-if [[ -z "$OPAMROOT" ]] ; then
-  export OPAMROOT=${HOME}/.opam
-fi
+export OPAMROOT=${OPAMROOT:-${HOME}/.opam}
 
 
 if [[ -d "$OPAMROOT" ]]