What kind of flour are you using? I have found that higher gluten holds structure better and a very active starter can also contribute to oven spring.

I switched from a high gluten flour (Grain Craft's Power Flour) to Cairnspring Mills Trailblazer bread flour and found that my loaves are baking flatter - I judge them as to whether they 'break the plane' defined by the opening of my 5 quart cast iron dutch oven.

I bought some bulk vital wheat gluten at the co-op last weekend and am going to experiment with boosting the gluten of the trailblazer flour, which is locally produced in WA state and does not use glyphosate as a drying agent. The power flour has great performance for bread and pizza, but it is a national brand and may not be as clean.

I'll try to update with results.

#foodstr