Making a big batch of roux is a hassle, so I'm investigating how to make my life a bit easier.
According to 'Ideas in food', you can make roux in a jar in a pressure cooker. Nice, but the quantity is too little for my needs.
In the Cajun cuisine you can make roux for gumbo in the oven. That won't work for me as I need it to work as a thickening agent. Maybe it would work at a lower temperature.
The problem is to lose the raw flour taste. I'm thinking of mixing the butter-flour as always, on the stove-top. Then transfer the batter to a sous vide bag and let it bathe for 12 h at 85ºC (at which point the starches should be gelatinized).
What do you think? Is 12h too long or too short? Is 85ºC high enough to lose the raw flavour?
Best Answer
In a roux, the starches are not normally gelatinized during the production of the roux--in fact, if you make your roux with oil rather than butter, there is no water present (other than latent moisture from the flour) to do so.
Roux thickened sauces must normally be brought to the boil; this is when the actual gelatinization takes place.
. . .
Roux is easy to prepare in larger batches, stove top. Simple use a larger pan, such as a six quart dutch oven.
Melt your butter or add your oil, then whisk in the flour. Cook for a couple of minutes (after the bubbling subsides if using butter), and you are good to go. Don't be afraid to turn the heat up as long as you are standing by, watching and stirring to prevent burning from hot spots.
Butter can foam up considerably, so use a large pot in comparison to the quantity of roux.
For dark roux, I would start stove top, and finish in the oven to reduce the likelihood of taking the browning too far, and reduce the labor of stirring required.
The roux can be refrigerated. You can scoop it with a spoon and add it to sauce at the simmer and whisk, and it will thicken almost instantly.
See also: Is there a technique for making larger batches of roux?