diff --git a/src/_zkapauthorizer/controller.py b/src/_zkapauthorizer/controller.py
index fc3196cd0b94e3af369a547ae06004e32c4af4d6..510e34aeae01121afdfa96773667ca08f3a7b5df 100644
--- a/src/_zkapauthorizer/controller.py
+++ b/src/_zkapauthorizer/controller.py
@@ -91,7 +91,7 @@ from .model import (
 )
 
 # The number of tokens to submit with a voucher redemption.
-NUM_TOKENS = 100
+NUM_TOKENS = 512000
 
 RETRY_INTERVAL = timedelta(minutes=3)