Why use the different flours in baking?

I know I should know this. Maybe I do, and pg brain is suppressing it somewhere? :rolleyes:

Why in some recipes, like the one I've put below, do they ask for all the different types of flour? Ie, plain flour, rice flour, and cornflour.

And is there any difference (in the end result) in using caster sugar instead of icing sugar in a situation like this recipe? I made something the other day (similar slice and bake biscuits) just with caster sugar, because I didn't have any icing sugar, and I think the icing one is too expensive to want to use two cups worth (it was nearly that much in the other recipe) to use in dough. Rather use it as icing, iykwim. The biscuits I made, I hadn't made before, so I can't compare them to how they *should* be.

Slice and Bake Cookies (from AWW "cookies" book)

250g butter, softened
1 ? cups icing sugar
1 tsp vanilla extract
2 cups plain flour
? cup rice flour
? cup cornflour
2 tblsp milk

Beat butter, sifted icing sugar, and vanilla in small bowl with electric mixer until light and fluffy. Transfer to large bowl; stir in sifted flours, in two batches, then add milk.

Divide the mixture in half. Knead each half on floured surface until smooth, then roll each half into 25cm logs. Wrap each log in baking paper; refrigerate about 1 hour or until firm.

Preheat oven to 160?C/140?C fan-forced. Grease oven trays; line with baking paper.

Cut logs into 1cm slices; place about 3cm apart on oven trays. Bake about 20 minutes. Cool on wire racks.


Sorry, another question about flour! I have a yummy recipe for buttermilk and sultana muffins, which asks for plain flour with baking powder. That's cool, I get the powder is to raise the muffins. But, can I just use self raising flour? I was talking to my Mum about this last week, and she made choccie muffins too, that she said were not good at all, and she thinks it is because she used SR flour, not plain + powder. I think they rose, they just made her feel ill. :dunno:
Again, its a cost thing :redface:, and I'm interested to know where I can substitute things. For the size batches of muffins I'm making atm, I use probably about a third of a container of baking powder in one go!

Any ideas? Thank you all you clearer thinking geniuses!

Flours have many different textures and compositions, so are better for use in some baked goods than others.
Things like more or less gluten, raising agents etc that make them better suited to different applications.
e.e. plain four does not rise the same way as SR flour, so some recipies that have plain flour will also have bi carb or baking soda in them as well. - So you probably could use SR flour instead, its worht giving a go to experiment.

As fpr sugar i would never use castor sugar in place of icing sugar (or pure icing sugar - different again) they are entirely different if you get a small bag of each you will see what i mean.
Icing sugar is a fine powder compared to castor sugar, which is finer than sugar, but no where near icing sugar.

Castor sugar is good for recipies here you need to cream butter and sugar together, icing sugar for icings, pure icing sugar for royal icing.

You may need Niliac the domestic goddess for a proper rundown :)

Self raising flour is plain flour with a standard amount of raising agents added. You can substitute SR for plain plus baking powder, you just need to get the proportions right. I just checked my baking powder container and it has a ratio of 2 tsp to 1 cup of flour. Where the recipe calls for plain flour plus baking powder it would most likely be due to the need for a different level of raising than what SR flour gives, so there might be 1 tsp added rather than the 2 needed to make SR flour. The would be no reason why substituting would have made your mum feel ill. The texture might be different, I suppose that could have done it. I have substituted many times without a problem and I am sure when I studied professional cookery that they taught us something about it. Sometimes I find it easier when I am not baking a lot to just have plain flour and baking powder on hand, that way I can bake anything.

As for sugars, best not to change them for the reasons rayray mentioned. I tend to hunt around for a recipe that has the ingredients I have one hand, rather than substituting something like sugar.

Yup..I agree with the plain and SR flour thing.
Although they are basically the same thing - I tend to follow what the recipe says and then it always comes out. Now to contradict myself - with the muffins - it really should not make any difference at all...biscuits might.
The cornflour is a thickening agent and plain flour will not substitute. The rice flour I am not sure...if it were me I would use pl flour instead but def use the cornflour.

With the sugars - castor and icing have very different textures which certainly do reflect in the finished product.

I know of the different textures in the sugars, and in Coles I only ever see 'pure icing sugar' and 'icing mixture' (or something like that, one is 'pure', and one is a 'mixture'). I should know of the different finished results, I made anzac biscuits once with raw sugar, and they were a bit weird, compared to the usual caster sugar.

Oh Cai.... Where are you.....?

I think Mum was feeling unwell anyway, not from the muffins. It just meant that my brother had to eat them all on his lonesome.... The poor guy!