I recently roasted a whole duck on a rack above the pan, pricked all over so the fat would cook out, and want to clean the drippings so I have only the duck fat. I had read some time ago that the proper method was to pour the drippings into a pot of water and boil it for 45 minutes to an hour. After cooling, the now pristine fat was to be skimmed off the water and put in a container for refrigeration and later use. In actual practice, a layer of foam with impurities formed on the top of the fat, and another layer of impurities formed under the fat on top of the water. Freezing it and trying to separate it that way hasn't worked either. It's lovely duck fat and I really want to keep and use it. I planned ahead and roasted the duck without salt so the fat wouldn't be salty.

  • 1
    It of course depends on the use case but I like to use duck fat as cooking oil when stir frying vegetables and then all the impurities (which are just duck pieces) can stay in.
    – quarague
    Feb 5 at 9:55
  • I render (good quality) bacon or roasted poultry fats all the time, and I don't add water. A small stainless saucepan, and a low simmer of the fat, when it stops 'sputtering' the water has been cooked out, and (most of) the 'bits' or impurities are floating or stuck to the pan. A quick fine strain into the jar, and done. Avoid too high a heat, or cooking too long after the sputtering stops, the impurities will burn and impart a not tasty carbon taste and the oil will be too dark. I see no reason not to do the same with the duck fat if not a large quantity. Feb 12 at 20:12

2 Answers 2


After boiling, refrigerate it until the fat is quite firm, pour off the water, then scrape off the top and bottom detritus. You can repeat this process with another round of boiling, but for most purposes I wouldn’t even do one— the flavors I’m trying to bring along with the fat are in the impurities as well.

  • Haven't tried that. But it sounds good. Feb 4 at 19:59

I save duck and goose fat all the time— I find that the key is to get the water separated out (as its the water that will cause spattering later). Any other “schmutz” can be skimmed off. Its not a problem in my kitchen if a bit remains. Much of that dirty scum is from various surface proteins from the meat, bones, and remains of organs ( such as bits of kidney which are often stuck to the backbone). Just as when making a stock, the scum can be dramatically reduced by quickly parcooking the bird in boiling water first. Bring a large pot of water to boil, drop the bird in, let it come back to a boil, take the bird out and rinse with cold water. Doing the same will also lead to cleaner rendered fat.

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