In a medium saucepan, heat the oil until shimmering. Add the flour and whisk until smooth and bubbly. Whisk in the chile powder, garlic, cumin, salt, and oregano. Whisk in the water.
Simmer the sauce for 10 minutes, whisking occasionally.
Pour the sauce into freezer-safe containers, leaving room for expansion. Chill completely in the fridge. If using glass jars, freeze uncovered until the sauce is firm. If using plastic, go ahead and secure the lids, label, and freeze. Once the sauce in the glass jar is frozen, add a labeled lid.
To use, thaw the sauce completely in the refrigerator and proceed with recipe.
Notes
Be sure to use ground chile instead of chili powder. There is a big difference between the two products. The first is dried ground chile peppers; the latter has salt and other spices added to it which will greatly change the flavor of the sauce.Homemade enchilada sauce is delicious to use on more than just enchiladas! Use this sauce as a chili or soup starter, to flavor taco meat, or to drizzle on nachos, quesadillas, burritos, and tamales.To freeze the sauce: chill it completely in portion-size containers before storing in the freezer. Two-cup containers are useful for making recipes such as enchiladas, but you may prefer freezing smaller portions to use on nachos, tamales, or wet burritos.You may make a double or triple batch. To do so, adjust the servings above to 8 or 12 cups so that you have the right proportions. If you make a bulk batch, use a large heavy stockpot.Promptly store leftovers in an airtight container in the refrigerator, for up to 3 days.Nutritional values are approximate and based on 1 cup.