Cooking For Engineers

[Guest]

What is the difference between unbleached and bleached all purpose flour. When would you use one over the over. If a recipe calls for bleached flour and you use unbleached, how much does it effect finished baking product.

[Thor]

All-purpose flour is aged somewhat to allow the color to lighten and to allow the proteins that ultimately make up gluten, the building block of many baked goods, to cure. These factors apparently make for better quality baked goods.

Unbleached flour is allowed to age on its own, with little or no chemical assistance (check the label). Bleached flour is chemically treated to reduce the time from milling to packaging, and for color control. Color wise, unbleached flour may have a yellowish or off white tint, while bleached flour is stark white. Other than color, which may be important for cakes or pastries, there is very little difference in result between the two all-purpose flours. Chlorine bleached all-purpose may damage some of the gluten forming proteins which would produce a slightly less bread-like, slightly more cake-like finished product.

The site below has tons of info on baking ingredients. It's unusually organised, but has good stuff.

http://www.baking911.com/index.htm

What are you baking??

[Lintballoon]

I always use King Arthur, they are the best! They never use any wierd chemicals to process their products.

[IndyRob]

I'm not an expert, but I believe unbleached flour is generally preferred for breads and pizza doughs. I've found it superior for making french bread and pizza.

I believe the primary difference is the amount of protein which gets turned into gluten upon agitation. In bread you usually want a lot of gluten to hold the air bubbles made by the yeast. So you use a high protein flour and knead the heck out of it.

In contrast, for, say, brownies where gluten is your enemy. You don't want brownies with the texture of bread. Most recipes limit mixing to 50 strokes. So you'd probably use all purpose bleached here.

Similarly, biscuits are often at the other extreme. Usually a low protein (cake?) flour is recommended (White Lily being the brand name that I recall).