diff --git a/google/refine/refine.py b/google/refine/refine.py
index c7c9b91..859f959 100644
--- a/google/refine/refine.py
+++ b/google/refine/refine.py
@@ -216,7 +216,7 @@ def new_project(self, project_file=None, project_url=None, project_name=None, pr
                     skip_data_lines=0,
                     limit=-1,
                     store_blank_rows=True,
-                    guess_cell_value_types=True,
+                    guess_cell_value_types=False,
                     process_quotes=True,
                     store_blank_cells_as_nulls=True,
                     include_file_sources=False,