At Eric's request, here is Hamelman's Five-Grain Levain.

As an introduction, Hamelman describes this recipe as "one of the most delectable table breads I have ever eaten."

Pre-ferment flour: 25%

Dough Yield (home): 3 medium loaves

Five-Grain Levain

Liquid Levain build:

8 oz bread flour (all purpose flour in the mid 11% protein range)

10 oz water

1.6 oz mature culture liquid (Hamelman uses a liquid culture of 125% hydration)