whenever i make a roux with just oil/fat and flour, it seems to come out lumpy most of the time. however, when i first start with some veggies in the pan (usually finely chopped onions, also sometimes carrots or celery), and oil/fat as well, then add the flour, it seems to prevent the lumps from forming in the roux.
is this just a coincidence, or is there something that is working to prevent lumping? in either case, what am i doing wrong to cause the lumps to form?
how quickly are you incorporating flour? the same technique that prevent women from being mocked for having lumpy oatmeal is used in everything. incorporate slowly and stir continuously. also do not create unnecessary temperature differentials when mixing ingredients unless you are supposed to, ie cold water for flaky pie crust
to visualize. developing starches from things like flour, the friction between the particles is doing all the work in processing that starch. so there needs to be a balance between water incorporation and friction. too much water at once, no friction and the starches dont process. too little water at a time and poor technique will lead to uneven processing
You melt the butter, stir in the flour on the stove, throw it into a 350 oven, and break it up/stir it around every 15 minutes or so until it reaches the color you want.
Yeah, it's dry and crumbly, but it keeps just fine on a shelf and works just as well as freshly made stuff.
>what am i doing wrong to cause the lumps to form?
Using the stove top instead of the oven.
Mix your oil and flour in a bowl until it's absolutely smooth, then toss that shit in a cast iron pan and into the oven at about tree fiddy, and then just monitor the color and give it a courtesy stir every half hour or so.
1) place X butter in vessel and apply middling heat until melted
2) place 1-2X of flour in the vessel and stir until incorporated then continue for another minute
3) turn off heat and slowly add fluid of choice, stirring constantly until sauce formed
4) restart heat and simmer for 15mins
the roux itself is never going to be smooth, but once you add fluid, then just keep stirring until it's lump-free