diff --git a/tutorials/multiphase/interFoam/les/nozzleFlow2D/system/controlDict b/tutorials/multiphase/interFoam/les/nozzleFlow2D/system/controlDict
index 00f2f205d0..2d7ac1e138 100644
--- a/tutorials/multiphase/interFoam/les/nozzleFlow2D/system/controlDict
+++ b/tutorials/multiphase/interFoam/les/nozzleFlow2D/system/controlDict
@@ -33,7 +33,7 @@ writeInterval   1e-06;
 
 purgeWrite      0;
 
-writeFormat     ascii;
+writeFormat     binary;
 
 writePrecision  8;