diff --git a/aliBuild b/aliBuild
index fbdd81f0..c85c2fd0 100755
--- a/aliBuild
+++ b/aliBuild
@@ -778,8 +778,9 @@ def doMain():
       h(str(time.time()))
     if spec["package"] in develPkgs and "incremental_recipe" in spec:
       h(spec["incremental_recipe"])
-      incremental_hash = hashlib.sha1(spec["incremental_recipe"]).hexdigest()
-      spec["incremental_hash"] = incremental_hash
+      ih = Hasher()
+      ih(spec["incremental_recipe"])
+      spec["incremental_hash"] = ih.hexdigest()
     elif p in develPkgs:
       h(spec.get("devel_hash"))
     spec["hash"] = h.hexdigest()
diff --git a/alibuild_helpers/utilities.py b/alibuild_helpers/utilities.py
index c37009db..dbd47446 100644
--- a/alibuild_helpers/utilities.py
+++ b/alibuild_helpers/utilities.py
@@ -284,6 +284,8 @@ class Hasher:
   def __init__(self):
     self.h = hashlib.sha1()
   def __call__(self, txt):
-    self.h.update(txt.encode('utf-8', 'ignore'))
+    if not type(txt) == bytes:
+      txt = txt.encode('utf-8', 'ignore')
+    self.h.update(txt)
   def hexdigest(self):
     return self.h.hexdigest()
diff --git a/tests/test_utilities.py b/tests/test_utilities.py
index 784c951a..66c53665 100644
--- a/tests/test_utilities.py
+++ b/tests/test_utilities.py
@@ -120,10 +120,13 @@ def test_Hasher(self):
   def test_UTF8_Hasher(self):
     h1 = Hasher()
     h2 = Hasher()
+    h3 = Hasher()
     h1(u'\ua000')
     h2(u'\ua001')
+    h3(b'foo')
     self.assertEqual(h1.hexdigest(), "2af8e41129115eb231a0af76ec5465d3a9184fc4")
     self.assertEqual(h2.hexdigest(), "1619bcdbeff6828138ad9b6e43cc17e856457603")
+    self.assertEqual(h3.hexdigest(), "0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33")
     self.assertNotEqual(h1.hexdigest(), h2.hexdigest())
 
 if __name__ == '__main__':