I tried Tartine whole wheat sourdough bread again. The recipe was adapted from Chad Robertson's 'White-Wheat Blend' in Tartine Book No. 3 and Maurizio's '90% Whole Grain Sourdough' recipe in foodtravelthought blog.
I had been struggling with baking this bread from Tartine Book No. 3 and had hit the wall a while ago, but this Maurizio's modified recipe was totally eye-opening and helped me a lot to break through the wall.
To make high-extraction flour, I sifted Community Grains 100% Whole Grain Hard Red Winter Wheat Flour to get rid of 30% bran out of it. But I miscalculated the weight of bran to remove, so it was actually 83% high-extraction flour instead of 70-75% one which Chad Robertson suggested in Tartine Book No. 3. To adjust the balance between whole grains and white flour, I added extra 10% bread flour to the flour mixture (with just a wild guess), so the total ratio of bread flour was 20%.
The oven spring was not so dramatic, but the inside crumbs have nice holes which I had never been successful with before. I used an oval basket for proofing the loaf, but somehow it ended up to be a round-shaped when baked.
The crumb was surprisingly soft for a loaf with high-percentage of whole grains.
This is highly recommended recipe for anyone who has been struggling with the original Robertson's recipe. I am very happy with the result.