diff --git a/tutorials/incompressible/simpleFoam/windAroundBuildings/system/controlDict b/tutorials/incompressible/simpleFoam/windAroundBuildings/system/controlDict
index 84140b15c6..2e44c6d58a 100644
--- a/tutorials/incompressible/simpleFoam/windAroundBuildings/system/controlDict
+++ b/tutorials/incompressible/simpleFoam/windAroundBuildings/system/controlDict
@@ -32,7 +32,7 @@ writeInterval   50;
 
 purgeWrite      0;
 
-writeFormat     ascii;
+writeFormat     binary;
 
 writePrecision  6;