diff --git a/085-pdfcrop.Rnw b/085-pdfcrop.Rnw
index 728bb61..3034468 100644
--- a/085-pdfcrop.Rnw
+++ b/085-pdfcrop.Rnw
@@ -5,7 +5,7 @@ knit_hooks$set(crop = hook_pdfcrop)
 @
 
 Cropped.
-<<test-a, crop=TRUE, fig.width=3, fig.height=3>>=
+<<test-a, crop=TRUE, fig.width=3, fig.height=3, cache=TRUE>>=
 plot(1)
 @