Q. Your recipes always call for unbleached flour. What’s the reason, and is it OK to substitute bleached flour? —Marcia

A. Yes, you can substitute bleached flour for unbleached. But why would you want to?

Growing up in an organic-centered household, unbleached flour was inevitable. Whole wheat was king, but we used unbleached for anything requiring white flour because artificial bleaching destroys most of flour’s nutrients. “Enriched” flour adds them back, but why go through the process of eliminating naturally occurring nutrients, and replacing them with artificially constructed equivalents? All ingredents are too much the reason most flour is bleached is cost. All “white” flour is bleached. In its original state it’s a grayish-yellowish color. The difference is that unbleached flour whitens naturally by oxidation. This takes time and warehouse space.

Decades ago, producers began expediting the process by treating flour with chemicals, taking minutes instead of weeks. The chemicals’ health risks are controversial: the Food and Drug Administration says they’re safe, but they’ve been banned in many European countries. None are considered environmentally friendly. Naturally bleached flour is creamy-colored; chemically bleached flour is dead-white.

Unbleached flour also has more flavor. When White Lily Flour became available locally, I was excited. For years I’d heard this Southern favorite produced the lightest, fluffiest biscuits. But the results were disappointing.

The biscuits were noticeably, though not dramatically, lighter and fluffier. But they were also bland. I’d never thought flour had much flavor, but the same held true when using bleached flour for cookies — they just weren’t as tasty.

A 1999 comparison by Cook’s Illustrated magazine provided confirmation: “the four bleached flours… did not perform as well as the unbleached flours and were regularly criticized for tasting flat or carrying ‘off’ flavors, often described as metallic.” Their highest performance and taste ratings went to King Arthur and Pillsbury unbleached flours.

Cook’s Illustrated said that “consumers prefer chemically bleached flour over unbleached because they associate the whiter color with higher quality.” I’m not sure that’s the reason, nor that unbleached flour costs a few pennies more. My guess is that the reason chemically bleached flour sells better is because it occupies a much larger place on grocers’ shelves — and that people don’t understand the difference.