Making Roux when Flour is Missing I like making sauces from scratch, starting with a roux.  Today, I discovered there's no flour in the kitchen.  A quick trip to the store is not possible.

What could I use instead?   

(Note that my question is similar to but not the same as Flour alternatives for roux. I have no reason to avoid wheat flour; I just don't have any around.)
Technically, you can make roux with any starch and any fat, per Harold McGee.

So use cornstarch or arrowroot or whatever you have.  Just avoid something with strong flavor like cornmeal.

Of course, the flavor and thickening properties will be those of the starch you use... And you probably don't want to make a brown roux with anything but flour because of the flavor difference.