Originally Posted by janachu
Hi-ratio flour can be used in recipes with a higher liquid content than for example, a sponge cake. As the grains of this flour are finer than usual flour, it allows for better absorption of liquids and so therefore if you are substituting it for biscuit/cake or bakers flour (larger grains, higher gluten content), you would naturally add more liquid to your recipe.
Actually it has nothing to do with the finer grain and everything to do with the type of wheat used. It is made with a softer red winter wheat that has a lower protein count, a lower ash count and a higher starch count. And not all cake flours are alike. The Swans Down available at most grocery stores is a completely different puppy than the hi-ratio cake flour I get at the last remaining flour mill in my area. My neighbor is the general manager there and we have lots of fun talking flour at dinner parties.
The bleaching of the flour is what will allow for more liquid. This process increases the ability of the starch granules to absorb liquid. Most of the time it is a beach flour that will work with a hi-ratio cake recipe rather than an unbleached flour.
You cannot get bleached flour overseas. It is not allowed by law. So you may get a different flour with different results. I do remember someone on the internet having success with flour from overseas when she microwaved it first. But unfortunately I do not have a link. Maybe if you go to The Cake Bible site and look around there you may find a link somewhere.