diff --git a/utils/hash_userid.py b/utils/hash_userid.py
index c9b40cc..b2cfd6c 100644
--- a/utils/hash_userid.py
+++ b/utils/hash_userid.py
@@ -8,4 +8,6 @@ pl.scan_parquet(file).with_columns(
     pl.col("user_id").cast(pl.String).add("Lt2N5xgjJOqRsT5qVt7wWYw6SqOPZDI7")
 ).with_columns(
     pl_hash.col("user_id").chash.sha2_256().str.head(16)
-).collect().write_parquet(file.replace(".parquet", "_pub.parquet"))
+).collect().write_parquet(
+    file.replace(".parquet", "_pub.parquet"), compression="zstd", compression_level=15
+)