This came up in a side discussion on another thread....thought it might get some response here.

All my cajun and New Orleans' cookbooks call for making roux with oil--some further specify  "not butter."  So that's the way I've done it.

Others said they always make it with butter--which sounds like it might actually taste better, although I know melted butter can be temperamental.

Any thoughts here on the pros/cons of both/either?

I personally always use butter and have never tried it with oil, so am no help with the pros and cons of each.  That said, I can kind of see why, in Cajun cooking, they might recommend oil rather than butter, since in that type of cuisine, you usually cook the roux until it's darker than a standard (light) roux.  Since butter contains solids, those are likely to burn and not taste very pleasant, so using an oil with a higher smoke point probably does work better for that type of roux.

(Disclaimer, I have never cooked anything Cajun, I'm just a cookbook/cooking magazine geek, so the above is all theoretical rather than practical!)

I think Lesley hit the nail on the head. Most roux use butter for flavor, but burned butter does not taste good, so that is probably why they don't use it in dark cajun roux. 

I have always used butter.  But I recall seeing on TV quite a while ago either Emeril or Paul Prudomme make a huge pan of roux using oil and flour.  They made enough for a month at least--or for a restaurant.  I only make enough for one meal at a time.  So I'm thinking the oil method is more tradionally southern.  Just guessing though.  From memory.

I think Lesley is right---all my cajun recipes call for a dark roux, and oil is much "safer" for that than butter.

I HAVE MADE LOTS OF ROUX. WHEN I LIVED IN BIRMINGHAM, AL MY FRIEND FROM MISSISSIPPI TAUGHT ME LOTS OF CAJUN DISHES. ONE WAS HER HINTS ON ROUX. ALSO, I LEARNED FROM JUSTIN WILSON. HE HAD A TV SHOW FOR YEARS ON PUBLIC TV CALLED "CAJUN COOKING" OR 'COOKING CAJUN." HE IS NOW DECEASED.

ROUX

PLAIN FLOUR (3 PARTS) OR 3/4 FLOUR

 OIL/BUTTER  (1 PART) OR 1/4 OIL/BUTTER.  MY FRIEND USED 1/2 REAL SALTED BUTTER (NOT WHIPPED OR LIGHT) AND 1/2 OLIVE OIL FOR THE OIL IN THE RECIPE.

FOR EXAMPLE, 3 CUPS PLAIN FLOUR, 1/2 CUP REAL BUTTER AND 1/2 CUP EXTRA VIRGIN OLIVE OIL

THIS MAKES A THICK ROUX, WHICH I AND ALL OF MY FRIENDS LIKE BETTER. IF YOU WANT A THINNER ROUX, USE 2 PARTS FLOUR TO 1 PART OIL.

 FOR GUMBO, YOU WILL BE ADDING WATER AND WINE. THIS WILL MAKE THE GUMBO THE PERFECT CONSISTENCY

MIX FLOUR , OIL AND BUTTER IN A HEAVY POT. I HAVE A SPECIAL GUMBO POT

COOK SLOWLY AS ROUX CHANGES FROM A CREAM COLOR ALL THE WAY TO THE COLOR OF A HERSHEY CHOCOLATE BAR. YOU HAVE TO STIR THE ROUX ALL OF THE TIME OR IT WILL BURN. MY BEST ROUX HAS TAKEN 1 HOUR TO BROWN. THAT COOKS THE FLOUR TASTE OUT. WHEN THE ROUX IS DONE, IT WILL HAVE A SHINE ON IT. ACCORDING TO JUSTIN WILSON, "IT WILL HAVE A SHINE ON IT LIKE THE SUNSET MAKES ON COLYETT BAY WHEN THE WATER AIN'T TOO MUDDY."

THEN ADD CHOPPED VEGS LIKE ONION, BELL PEPPER, AND CELERY. TOO MUCH BELL/GREEN PEPPER AND CELERY WILL KILL THE TASTE. ONION IS OK. AFTER THOSE HAVE COOKED SOME, ADD CHOPPED PARSLEY AND GREEN ONIONS. THEN ADD A LITTLE COLD WATER AND THEN ADD FRESH CHOPPED GARLIC.

THIS ROUX CAN BE USED IN GUMBO, SAUCE PIQUANT, ETC.

DO NOT FORGET TO STIR CONSTANTLY. I USUALLY MAKE A DOUBLE BATCH AND FREEZE HALF OF THE ROUX FOR LATER. IF IT POPS ON YOU WHILE COOKING IT WILL BURN, SO USE A LONG SPOON AND KEEP HEAT  WHERE IT IS JUST BARELY SIMMERING.

IF YOU LIKE CAJUN FOOD, TRY JUSTIN WILSON'S COOKBOOKS. THE BOOK GOURMET AND GOURMAND 1985 HAS A PICTURE OF ROUX FROM START TO FINISH. THIS REALLY HELPS TO SEE THE STAGES OF COLOR  FROM CREAM COLOR TO DARK BROWN. I HAVE ALL OF HIS BOOKS AND LOVE THEM ALL. HIS RECIPES FOR ALL KINDS OF GUMBO ARE THE BEST. ALSO, HIS JAMBALAYA IS WONDERFUL. WHEN HE CALLS FOR ANDOUILLE SAUSAGE, USE ONLY THE REAL THING.

WHEW, I AM HUNGRY FOR GUMBO!!

MARY