Bad results using vital wheat gluten in low gluten flour biga
I normally use either Italian 00 flour or Hogdsen's Mill AP flour (either of which has about 9.8-10% protein per the mill specs) to make my Rosetta Rolls. I prepare a biga at 50% hydration with 90% of the flour and pre-ferment 12-16 hours. I add diastatic malt powder, water (52-55% final hydration), salt, and the rest of the flour for the final mix.
Not having enough of either of these two flours on hand, but having some White Lily AP (8% protein per the mill specs) and some fresh vital wheat gluten, I decided to try and boost the gluten content of the White Lily to arrrive at a protein level of 10%. The vital wheat gluten had a 67% protein level, so I calculated that I would need 28 g to bring my White Lily flour (850 g) up to about a 10% protein level.
Typically, I can see my biga (using a straight dough) double in size after 2-4 hours with lots of large bubbles forming. With this mixture, however, it barely moved. Not much change even after 12 hours.
In final mixing, I could not get a good windowpane no matter how much I mixed. The dough would tear with the least bit of stretching. The baking results were not great either. I got a decent rise, but not anything like I get with a straight dough.
I have used the White Lily before by mixing it with bread flour to strengthen it, with good results, but just adding the vital wheat gluten seems not to work. I replicated the test today, just to be sure, with the same poor performance.
What's happening here?