Jeffrey Hamelman's wonderful sourdough multigrain, found in Bread: A Baker's Book of Techniques and Recipes, is one of my favorite sandwich breads - along with my Soudough Onion Rye.
One of the delightful aspects of this bread is that it lends itelf to improvisation when it comes to what constitutes the multigrain mix. Can't find rye chops or cracked rye easily? No problem, try substituting steel cut oats. And so on.
In my most recent iteration of his bread, I used whole wheat flour, whole rye flour, steel cut oats, rolled oats, flaxseeds and toasted sunflower seeds. The latter 4 grains were mixed in a cold soaker and allowed to sit overnight, softening the seeds and allowing the water to draw out nutrients which otherwise - especially in the case of flaxseeds - would be lost since unsoftened the seeds are largely undigestible.
The hydration in Hamelman's recipe is 98%, which seems extreme, and would yield something resembling a batter rather than a dough, were it not for the seeds which absorb all of the water in the soaker. Still, this is a sticky dough, and you need to resist the urge to add additional flour which only results in brick-like bread.
Instead, I rely upon two folds during the initial 2 hour fermentation - at 40 minute intervals - to build strength in the dough.
If baked the same day, .8% yeast is added for extra leavening power. However, I've found superior results (in terms of flavor) by retarding the shaped loaves overnight (for 18 hrs) at 42 degrees F. And in that case, no commercial yeast is added to the final dough mix.
Along with allowing for more flavor development, another virtue of overnight fermentation of the shaped loaves is that they can be placed into the preheated oven directly from refrigeration. So you avoid the additional proofing time that comes if you bake the same day or opt for a bulk retardation of your dough. (The downside is that you need adequate space to place shaped loaves for retarding).
Next day the shaped loaves - one batard and one boule - were loaded into the oven preheated to 450 degrees F, with steam. After 15 minutes the steam source was removed and the temperature lowered to 400 degrees F. The loaves, which weighed slightly more than 1.5 lbs prebaked, were baked for an additional 30 minutes, for a total baking time of 45 minutes. Because of the high level of hydration, this bread requires a slightly extended baking time (as opposed to a 40 minute bake for a 1.5# loaf).
As you can see, the result is a nice crumb - moist and full of good flavor from the multigrains.
A most pleasing sandwich - or toast - bread!