diff --git a/src/languedoc/train.py b/src/languedoc/train.py
--- a/src/languedoc/train.py
+++ b/src/languedoc/train.py
@@ -113,8 +113,9 @@ def train(data_dir: str, model_path: str
 
 				lang_samples.add(text)
 
-	with gzip.open(model_path, mode="wt", encoding="utf-8") as f:
-		json.dump([sample_set.create_model().export() for sample_set in samples], f, ensure_ascii=False)
+	with gzip.GzipFile(model_path, mode="wb", mtime=0) as f:
+		s = json.dumps([sample_set.create_model().export() for sample_set in samples], ensure_ascii=False, sort_keys=True)
+		f.write(s.encode("utf-8"))
 
 	print(cross_validate(samples))