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Suppose I have many pounds of fat to render. (Sometimes people have 100 pounds!) How can I do this efficiently?

Should I use a pot on the stove, a slow cooker, or the oven? How many pounds should I render in each batch? Do I need to add water?

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2 Answers 2

Unless you've got industrial type equipment, I wouldn't do more than about 1-1.5 lbs at a time. Here's a hint, cube the fat (1 inch cubes) and then partially freeze it. 45 - 75 minutes or so in the freezer will give you fat you can handle without it melting and that can be coarsly ground in a food processor or meat grinder without making a gross mess. Some people add water, I wouldn't. Just keep the flame (or burner) very low. Use a heavy pot, preferably cast iron. If you do it nice and slow you should get cracklin and tallow that barely needs to be clarified, or not at all. Figure about an hour on the low end up to two hours for the fat to completely render.

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And why can't you do many pounds at once in a large heavy pot, especially if it's in the oven? –  Jefromi Nov 22 '13 at 21:02
I've only ever done it on the stove, I've never seen it done in the oven. I've never done beef, only moose, but I'm sure it's the same. On the stove, more than 1.5 pounds is just too hard to handle. It doesn't melt/cook evenly without clumping up, trying to burn and just getting difficult. –  Jolenealaska Nov 22 '13 at 21:06
According to this site, it is pretty easy to do in the oven, and he doesn't specify a maximum payload. –  SAJ14SAJ Nov 22 '13 at 21:43
I don't know whether it's true, but I was taught to always go all the way to cracklin without pouring off the fat, that doing it partway then returning the solids to the pan results in cloudy tallow that doesn't taste right. I have no basis for that other than that is how I was taught by the old sourdough that taught me. Also, that was on the stovetop, not the oven. So, I dunno, other than what I know. –  Jolenealaska Nov 22 '13 at 21:56

If I was to try and render the huge amounts of fat you have hinted at I would do it in water. You'd need a suitably large pan obviously to fit the quantity needed.

  1. Fill pan with fat.
  2. Cover fat in water.
  3. Simmer slowly for a good few hours.
  4. Leave to set in fridge.
  5. Remove the now solid fat from the top.
  6. Depending on the outcome of the above fat, re-melt and strain through a cheesecloth.

Most of the sediment will end up on the bottom of the pan but some may get trapped in the top layer.


Well if you think about when you're making a meat stock for example, you simmer the contents for hours. Fat floats to the top, you ladle it out then pass the result through fine sieve. All you're trying to do it the same but instead of a tasty bottom stock you want the fat.

This method is more likely to give a pure, clean and untainted fat. Roasting or frying is going to cause burnt bit's of meat etc, the flavor of which I'm sure will be present in the resulting fat. Also any smoke cause by the roasting method is again going to taint the end product.

Regarding the water at the bottom, an untested thought/thory would be to add a couple of pig trotters to the mix. The resulting gelatin will in theory set the water solid at the bottom also grabbing all the sediment's and other juices. Then allowing you to turn the entire pan over heat slightly with a blowtorch and remove the pan. Then with a warm knife slice the bottom(now top) layer off to remove all the unwanted stuff.

I see no reason why this method couldn't be done on an infinite scale only limited by pan size.

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If you mean to do it on the stove, this definitely won't scale infinitely; you won't be able to keep the whole pot hot without overheating it at the bottom. –  Jefromi Dec 25 '14 at 2:18
I think that is why when ever you See industrial kitchens on TV the big pots all have mechanical arms stirring... If you have a hob at home for a pot that big I'll be very very surprised. I wouldn't get one through my door. –  Doug Dec 25 '14 at 8:39
Even a big (home use, not commercial) stock pot would give you trouble, I think. –  Jefromi Dec 25 '14 at 14:09
Considering fat melts at 40-50 degrees Celsius, the emulsion stage of fat in water is between 90-100 degrees Celsius and the simmer point of water a sea level is 80-90 degrees Celsius, if you keep you're pot just below any form of a simmer I see no reason for over heating. The biggest pot I've used for beef stock/jus is 100L cooked over night (24 hours-ish) never had any issue with the fat from the bones emulsifying in my stock causing any form of cloudiness and a perfect layer of (dirty*) fat on the top. If you can fit a pot that large on your home hob I would be impressed.*Dirty because- –  Doug Dec 25 '14 at 20:35
- cont - when we make our stocks we are not interested in the fat, so all the flavors present in the stock remain in the fat. As I suggested in my answer, if you doing this with the intention of harvesting the fat instead of the stock you would presumably ensure there was nothing in the pan to taint the flavor of your resulting fat. Though thyme flavored beef fat may be appealing... –  Doug Dec 25 '14 at 20:38

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