diff --git a/src/levanter/data/mixture.py b/src/levanter/data/mixture.py
index 21cf8ba02..23f2ba37d 100644
--- a/src/levanter/data/mixture.py
+++ b/src/levanter/data/mixture.py
@@ -35,11 +35,12 @@ def __init__(
         self,
         datasets: Mapping[str, ShardableDataset[T]],
         weights: Dict[str, float],
-        stop_strategy: str = StopStrategy,
+        stop_strategy: str = StopStrategy.FIRST_STOP_STRATEGY,
         key: int | PRNGKeyArray = 0,
     ):
         self.datasets = datasets
         self.weights = MixtureDataset._normalize_weights(weights)
+    
         if stop_strategy not in [StopStrategy.FIRST_STOP_STRATEGY, StopStrategy.ALL_STOP_STRATEGY]:
             raise ValueError(f"Stop strategy {stop_strategy} is not supported.")
         print(f"=== class MixtureDataset: self.datasets.keys() = {self.datasets.keys()}, self.weights = {self.weights}, stop_strategy = {stop_strategy} ===")