diff --git a/mhcflurry/class1_neural_network.py b/mhcflurry/class1_neural_network.py
index 7e3e667f66d49ffffda0a6a044ae40cf5d9f18b0..f47a3eeb7a2e243cd6779c5a9eab50a4185a241b 100644
--- a/mhcflurry/class1_neural_network.py
+++ b/mhcflurry/class1_neural_network.py
@@ -70,6 +70,7 @@ class Class1NeuralNetwork(object):
     """
 
     input_encoding_hyperparameter_defaults = HyperparameterDefaults(
+        alignment_method="pad_middle",
         left_edge=4,
         right_edge=4)
     """