diff --git a/app/models/concerns/product_on_demand.rb b/app/models/concerns/product_on_demand.rb
new file mode 100644
index 0000000000..0ad101e7ca
--- /dev/null
+++ b/app/models/concerns/product_on_demand.rb
@@ -0,0 +1,10 @@
+require 'active_support/concern'
+
+module ProductOnDemand
+  extend ActiveSupport::Concern
+
+  def on_demand=(value)
+    raise 'cannot set on_demand of product with variants' if variants.any?
+    master.on_demand = value
+  end
+end
diff --git a/app/models/spree/product_decorator.rb b/app/models/spree/product_decorator.rb
index 8c0571558a..a7aefcee48 100644
--- a/app/models/spree/product_decorator.rb
+++ b/app/models/spree/product_decorator.rb
@@ -1,8 +1,11 @@
 require 'open_food_network/permalink_generator'
 require 'open_food_network/property_merge'
+require 'concerns/product_on_demand'
 
 Spree::Product.class_eval do
   include PermalinkGenerator
+  include ProductOnDemand
+
   # We have an after_destroy callback on Spree::ProductOptionType. However, if we
   # don't specify dependent => destroy on this association, it is not called. See:
   # https://github.com/rails/rails/issues/7618
diff --git a/app/serializers/api/admin/product_serializer.rb b/app/serializers/api/admin/product_serializer.rb
index ed14f3a2f7..e84588128f 100644
--- a/app/serializers/api/admin/product_serializer.rb
+++ b/app/serializers/api/admin/product_serializer.rb
@@ -1,7 +1,7 @@
 class Api::Admin::ProductSerializer < ActiveModel::Serializer
-  attributes :id, :name, :sku, :variant_unit, :variant_unit_scale, :variant_unit_name, :inherits_properties
-
-  attributes :on_hand, :price, :available_on, :permalink_live, :tax_category_id, :import_date, :image_url, :thumb_url
+  attributes :id, :name, :sku, :variant_unit, :variant_unit_scale, :variant_unit_name,
+             :inherits_properties, :on_hand, :price, :available_on, :permalink_live,
+             :tax_category_id, :import_date, :image_url, :thumb_url
 
   has_one :supplier, key: :producer_id, embed: :id
   has_one :primary_taxon, key: :category_id, embed: :id
diff --git a/spec/models/concerns/product_on_demand_spec.rb b/spec/models/concerns/product_on_demand_spec.rb
new file mode 100644
index 0000000000..8ff11302cd
--- /dev/null
+++ b/spec/models/concerns/product_on_demand_spec.rb
@@ -0,0 +1,28 @@
+require 'spec_helper'
+
+describe ProductOnDemand do
+  describe '#on_demand=' do
+    context 'when the product has no variants' do
+      let(:product) { create(:simple_product) }
+
+      before do
+        product.variants.first.destroy
+        product.variants.reload
+      end
+
+      it 'sets the value on master.on_demand' do
+        product.on_demand = false
+        expect(product.master.on_demand).to eq(false)
+      end
+    end
+
+    context 'when the product has variants' do
+      let(:product) { create(:simple_product) }
+
+      it 'raises' do
+        expect { product.on_demand = true }
+          .to raise_error(StandardError, /cannot set on_demand/)
+      end
+    end
+  end
+end