diff --git a/djangoshaker/views.py b/djangoshaker/views.py
--- a/djangoshaker/views.py
+++ b/djangoshaker/views.py
@@ -69,7 +69,9 @@ class UserView(TemplateView):
 def add_user_ingredient(request, ingredient_id):
     ingredient = get_object_or_404(Ingredient, pk = ingredient_id)
 
-    if not request.session['user_ingredients']:
+    if 'user_ingredients' not in request.session:
+        request.session['user_ingredients'] = [ int(ingredient_id) ]
+    elif not request.session['user_ingredients']:
         request.session['user_ingredients'] = [ int(ingredient_id) ]
     elif not ingredient_id in request.session['user_ingredients']:
         tmp_ings = request.session['user_ingredients']