When bleached wheat flour is mixed with water in an electric blender, would the resulting liquid be a reasonable substitute for milk or heavy cream in most soups and chowders?
Is it possible to increase the fat content with vegetable oil?
When bleached wheat flour is mixed with water in an electric blender, would the resulting liquid be a reasonable substitute for milk or heavy cream in most soups and chowders?
Is it possible to increase the fat content with vegetable oil?
No; flour and water (starch and water) is not a substitute for milk or cream (fat emulsion in water), no matter how similar in visual appearance the suspended flour is to milk.
If you are aiming to use the flour as thickening, then you can create a loose paste with cold water and then add to your soup, but it won't behave like milk or cream.
As a quick search will tell you, there are numerous vegan alternatives to cream and milk that might work, the best known of these would be coconut cream, which is a similar emulsion to animal milk. However, coconut cream tends to have a strong coconut taste, so won't necessarily work in a soup, though it might in a fish/seafood chowder.
Many of the other alternatives are so-called "nut milks" which are a suspension of proteins leached from nuts. You can mix/blend these with oil to make a substance that behaves like cream.
For soups, bisques, and chowders, can a chef prepare a vegan substitute for milk by mixing white bleached wheat flour with water [and vegetable oil]?
Yes, but not the way you describe it. While it will never be the same as using milk, if you have all the ingredients for a soup but cannot use milk, you will be able to make a meal by using wheat flour and vegetable oil to make a roux. This can then be incorporated into the soup to provide the thickening, fat content and flavour presentation that milk provides. I would probably add some of the soup to the roux to get it to mix, but one could use water.
How close this will be to the original using milk will depend on the recipe, but I think with most soups you could get something approximating what you could get with milk, it could be closer to what you get with nut milks as I find these have quite distinctive flavours.