This isn't uncommon when dealing with whole grain loaves, Saskia! The gluten structure of your loaves will always be a bit more tenuous in these types of breads. You can try adding a bit of vital wheat gluten into your dough to help strengthen it a bit, and also scoring your dough while it's chilled from the fridge. But some extra expansion is typically to be expected. Best of luck, and happy baking!

• Reply