Can using a poolish or biga preferment help me make a less dense wholemeal bread?
I think I solved this myself in the end.

Basically I used the same recipe as before, however instead of a biga as I had planned, I decided to try my hand at sourdough. I had started making a starter a while go and thought it was time to give it a go.

This is the second time I tried sourdough, but the first time my starter smelt disgusting so I threw it out.

To activate my starter, I fed it the total amount of wholemeal that I was going to add. Let it sit for 2 hours, and it doubled in size.

I also added a touch more water at 75% hydration. I used the stretch and folding method instead of machine kneading - 4 folds every 30 minutes, 5 times in total. It had a long proof in the fridge for 16 hours, then an hour to come to room temp, shaped and stuck it in a proofing basket, and about 2 hours after shaping it rose again. Also took care when shaping not to knock back too much, keeping as much gas in it as possible.

The result seems almost perfect, even though I say so myself. It's light and airy and bubbly, and delicious, very mild, hardly any sourness at all.  I have to say I'm pleasantly surprised.  It took a while though, almost 24 hours really.

I think the same would have happened with a biga/preferment, I think the key must be long proofing, giving it time to ferment, and stretching and folding to develop the gluten.  I will try it with a biga another time I think.