diff --git a/Makefile b/Makefile
index 49ceaebccb4f5216bcf1caefa3b22b65e0c2df77..3e2838aecba22f715b2c6cd85f53f46673dbcf98 100644
--- a/Makefile
+++ b/Makefile
@@ -11,7 +11,7 @@ COVER_PACKAGES=hbp_nrp_virtual_coach
 DOC_MODULES=hbp_nrp_virtual_coach/doc
 DOC_REPO=--doc-repo ssh://bbpcode.epfl.ch/infra/jekylltest
 
-PYTHON_PIP_VERSION?='pip>=19'
+PYTHON_PIP_VERSION?=pip>=19
 
 ##### DO NOT MODIFY BELOW #####################