Man, it's all too much. I used to be content with my good old all-purpose (unbleached) white flour. Then I experimented with other types, and before you know it I was in over my head. I need some clarifying, or a point in the right direction over some quiddities.
1: Bleached all-purpose: Lisa Yockelson calls for it plenty in "Baking By Flavor," she says it produces a softer crumb when compared to the coarser crumb of unbleached. Does anyone have an opinion on this topic?
Check out this link to see a relevant flour question with pictures of a recipe gone slightly awry (I could use some help on that too if you've got time...)http://forums.egullet.org/index.php?showtopic=56381
2: As for sifting flour, some flour says it's "pre-sifted," if so, does it need to be sifted again. With the prevalence of the word "sift" in recipes, I would be suprised if the author didn't just mean sift regardless of the flour you use. What do ya think?
Thanks for you time!
a) I use unbleached all purpose for just about everything. The bleaching that wheat flour endures is in no way comparable to the process that produces white sugar, so there's no parallel there. Perhaps (just perhaps) unbleached flour has a slightly different texture than bleached, but unless you are truly fanatical I can't imagine it would be something you'd notice for normal baking purposes. When making a light and delicate cake (angel food or similar) use cake flour. I've never seen unbleached cake flour, so you're stuck with bleached.
b) I rarely sift. I lightly spoon the flour into a measuring cup and remove the excess by running a knife across the top of the cup. The flour doesn't compact, and unless it's been stored badly for a long time it really isn't likely to have lumps. For normal purposes - don't bother to sift. It's just one more step. However, again, if you're making a cake where a very light texture is important (angel food again) yes, I'd sift. Probably twice. Not to get rid of lumps, but to make sure the flour was very airy.
You should sift. Even "pre-sifted" flour, which may be free of lumps and little pebbly-things (although I wouldn't trust it), gets compressed during shipping and storage, when it has the weight of its fellow bags on it. If you're American, or using American recipes, the only way to get the right volume of flour is by sifting when it's called for.
As for bleached/unbleached, I don't think I've tried bleached in years, if ever - my flour tends to come from Whole Foods. Not being an especially organic/carb-phobic sort, I think I'd try it if I saw it. This may not be a good comparison, but bleached white sugar is certainly in smaller grains than less processed versions. If the same is true for flour, I can imagine a very soft, lovely crumb.
I'll weigh in on the sifting issue.
I think even though the bag says pre-sifted, if you have the time, always sift you own flour, and other dry ingridents like baking powder and baking soda. You'll see lumps when you sift, and being lump free is another step towards better baked goods.