Just wanted to register the results using a stiff levain. I took some of my 100% hydration starter and built the levain in two steps. The first build was also 100% hydration while the second build was a stiff version with hydration around 50%. I think the results have been better than expected based on using AP flour, since it does not have very strong gluten. Let me walk you through the method used:
Ingredients
60 gr stiff levain @ 50% hydration (20 gr water; 40 gr flour)
30 gr whole wheat stone ground flour
30 gr rye
180 gr AP flour
184 gr water
3 gr malt
splash of honey and olive oil
5 gr salt
Levain build 1
15 gr water
10 gr starter @ 100% hydration
15 gr flour
Ferment around 8 ~10 hrs (at 21C temperature)
Levain build 2
All levain from build 1 (40 gr)
20 gr flour, all mixed well and light kneaded
Ferment for another 8 hours
Method
1) cut the stiff levain into small pieces, add water and leave it for 10 min to dissolve and smooth out some of it
2) add all flour, malt, honey, and olive oil. Mix all together and "fermentolize" for 30 min without salt
3) add salt and knead for 1 min; rest for 10 min
4) knead again for a min or two; and rest for another 10 min
5) stretch and fold three times every 30 min apart. In my case I used the double hand method
6) bulk ferment for few hours (about 4 hours or so) until some bubbles show up
7) pre-shape dough and rest for 30 min on the counter
8) final shape, place it in the brot form, and cold proof for few hours (8 hrs in my case) at 6C ~ 7C
9) pre-heat the oven to 250C, load the loaf, steam the oven and bake at 230 C for 15 min, and then remove steam to bake until golden (i baked on a stone and it took about 27 min to reach the point)
Cool down and enjoy. Considering it is not a strong flour with apparent lack of decent gluten, I am quite happy with the results, including oven spring and airy crumb. I believe the stiff levain has contributed to the results and for this reason I wanted to log the results. I plan on building levain in two stages from now on, and use the stiff version to bake.