7

votes

Can long cooking of bone broth create rancidity?

Answered on September 12, 2014
Created October 12, 2011 at 2:19 PM

It may be my imagination but whenever I do a longer simmer to make bone broth-- say over 7 hours-- it seems like the fat in the broth begins to smell and taste slightly rancid. Possibly more so with chicken or turkey broth which I know are higher in PUFAs. But I've never heard this cautioned about bone broth, in fact, most people say the longer cooking the better.

The question is, why wouldn't several hours of cooking turn the PUFAs in chicken broth rancid? If some rancidity is an issue, is it best then to skim out the fat in long-cooked poultry broths (which as a huge fathead I usually don't do)?

121a16aded2bed8dca492d3c9662ef4c

(1327)

on May 04, 2012
at 04:56 PM

Is 100°C a simmer temperature? That's the temperature at which water boils.

32f5749fa6cf7adbeb0b0b031ba82b46

(41747)

on January 15, 2012
at 02:00 PM

Either way, I'd anticipate that after 6-36 hours of simmer time, the stock is pretty sterile.

32f5749fa6cf7adbeb0b0b031ba82b46

(41747)

on January 15, 2012
at 01:59 PM

Rancidity does not refer to bacterial growth. It's refers to the chemical degradation of the components, specifically we're talking about degradation/oxidation of the fat.

32f5749fa6cf7adbeb0b0b031ba82b46

(41747)

on October 28, 2011
at 03:05 PM

Paul, it doesn't take much oxygen to do significant oxidation.

47a42b6be94caf700fce9509e38bb6a4

(9647)

on October 25, 2011
at 06:58 AM

@Matthew, Rockgrrl, Kent. What about: cooking on the stove versus cooking in a slow-cooker? My slow cooker seems to do a pretty good job of sealing off its contents from the air; that's why it works so well, right? Because the heat is sealed in there? Is this a negligible distinction as far as oxygen is concerned though? Somehow I suspect Matthew might have some ideas about this. I would research it myself but I've had too much to drink.

47a42b6be94caf700fce9509e38bb6a4

(9647)

on October 25, 2011
at 06:54 AM

Hmmm... interesting. I use veggies from the very beginning of my 24-hour process and they have never made my broths rancid-tasting. Though of course different people have different palates. For data purposes: I use: red onions, celery, peppercorns, a little carrot, vinegar, lemon, bay leaf.

47a42b6be94caf700fce9509e38bb6a4

(9647)

on October 25, 2011
at 06:49 AM

Hmmm... interesting. I use veggies from the very beginning of my 24-hour process and they have never made my broths rancid-tasting. Thought of course different people have different palates. For data purposes: I use: red onions, celery, peppercorns, a little carrot, vinegar, lemon, bay leaf.

32f5749fa6cf7adbeb0b0b031ba82b46

(41747)

on October 12, 2011
at 06:22 PM

@Rockgrrl- Even at a simmer temperature (100C), I'd wager significant oxidation occurs and the longer your cook it, the more fats that will oxidize. This is true of all cooking processes (open to the air). There was a recent discussion of oxidized cholesterol in ghee that should be relevant to your question as well. IIRC, about 10-15% of cholesterol in ghee ends up oxidized during its preparation. Extrapolate that to your system.

3f11b5fda91063846bba45daac3541bd

(1186)

on October 12, 2011
at 05:23 PM

The original question is, is it rancid? IF so, I don't want to save to cook with it. I don't mind the flavor, I'm just wondering if there's an anti-nutrient problem here.

77877f762c40637911396daa19b53094

(78467)

on October 12, 2011
at 04:08 PM

Well Rockgrrl, just skim it off and keep it for cooking with.

3f11b5fda91063846bba45daac3541bd

(1186)

on October 12, 2011
at 03:45 PM

I realize this is possible but still trying to establish if there is a health reason to do so. Otherwise I value my pastures poultry fat and would rather keep it in my soup.

6714718e2245e5190017d643a7614157

on October 12, 2011
at 03:31 PM

I agree with Kent, chill it and remove the fat. I cook my bones in a crock pot on low for 24 hours, remove the bones, let it cool and then refrigerate the broth. The next day I skim off all the fat on top of the gelatin with ease.

3f11b5fda91063846bba45daac3541bd

(1186)

on October 12, 2011
at 03:24 PM

Always assumed those instructions were motivated by culinary tastes. Is it possible that it's because the fat is overcooked (rancid) and hence less tasty? Or is it just dislike of overall fatiness (which I personally prefer)?

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11 Answers

5
07ca188c8dac3a17f629dd87198d2098

(7970)

on October 12, 2011
at 03:02 PM

Usually instructions I've seen for making broth suggest removing the fat - often more easily accomplished after you've chilled your broth - all the fat rises to the top and solidifies, and is easily plucked away from the delicious, nutritious gelatin.

Whether that's due to rancidity or not, I can't say for sure. But I wouldn't imagine that low a temperature would make the fat rancid, even after 24 hours.

3f11b5fda91063846bba45daac3541bd

(1186)

on October 12, 2011
at 03:45 PM

I realize this is possible but still trying to establish if there is a health reason to do so. Otherwise I value my pastures poultry fat and would rather keep it in my soup.

6714718e2245e5190017d643a7614157

on October 12, 2011
at 03:31 PM

I agree with Kent, chill it and remove the fat. I cook my bones in a crock pot on low for 24 hours, remove the bones, let it cool and then refrigerate the broth. The next day I skim off all the fat on top of the gelatin with ease.

3f11b5fda91063846bba45daac3541bd

(1186)

on October 12, 2011
at 03:24 PM

Always assumed those instructions were motivated by culinary tastes. Is it possible that it's because the fat is overcooked (rancid) and hence less tasty? Or is it just dislike of overall fatiness (which I personally prefer)?

3f11b5fda91063846bba45daac3541bd

(1186)

on October 12, 2011
at 05:23 PM

The original question is, is it rancid? IF so, I don't want to save to cook with it. I don't mind the flavor, I'm just wondering if there's an anti-nutrient problem here.

77877f762c40637911396daa19b53094

(78467)

on October 12, 2011
at 04:08 PM

Well Rockgrrl, just skim it off and keep it for cooking with.

32f5749fa6cf7adbeb0b0b031ba82b46

(41747)

on October 12, 2011
at 06:22 PM

@Rockgrrl- Even at a simmer temperature (100C), I'd wager significant oxidation occurs and the longer your cook it, the more fats that will oxidize. This is true of all cooking processes (open to the air). There was a recent discussion of oxidized cholesterol in ghee that should be relevant to your question as well. IIRC, about 10-15% of cholesterol in ghee ends up oxidized during its preparation. Extrapolate that to your system.

121a16aded2bed8dca492d3c9662ef4c

(1327)

on May 04, 2012
at 04:56 PM

Is 100°C a simmer temperature? That's the temperature at which water boils.

3
2c4b2d9c824982cf26bddb4cc1d65069

on October 25, 2011
at 05:54 AM

Something just dawned on me. Did you put veggie aromatics in your broth? I ask because if you put those in early during a long cooking process, they will get very bitter and taste rancid. I am pretty sure that is what happened in my case. This time around, I just have the bones in there. Any aromatics can be added during a quick boil before using.

47a42b6be94caf700fce9509e38bb6a4

(9647)

on October 25, 2011
at 06:54 AM

Hmmm... interesting. I use veggies from the very beginning of my 24-hour process and they have never made my broths rancid-tasting. Though of course different people have different palates. For data purposes: I use: red onions, celery, peppercorns, a little carrot, vinegar, lemon, bay leaf.

47a42b6be94caf700fce9509e38bb6a4

(9647)

on October 25, 2011
at 06:49 AM

Hmmm... interesting. I use veggies from the very beginning of my 24-hour process and they have never made my broths rancid-tasting. Thought of course different people have different palates. For data purposes: I use: red onions, celery, peppercorns, a little carrot, vinegar, lemon, bay leaf.

3
66974b2cb291799dcd661b7dec99a9e2

(11121)

on October 13, 2011
at 04:39 AM

When I make bone broth I usually simmer it 24-36 hours, never had an issue. The tallow that floats to the top is great. I only make beef bone broth though, every weekend.

3
0bc6cbb653cdc5e82400f6da920f11eb

(19245)

on October 12, 2011
at 10:49 PM

This question brings up several points for me.

I cannot speak from experience as I have never made stock for more than 5 hours as I have only made stock in a pan on a stove.

I do not know if fat becomes rancid when making stock, I expect no one has ever tested it.

Heating food in water with the heat remaining below 100 degrees Celsius usually greatly reduces oxidation of fats. Fats oxidise much faster when exposed to dry heat.

I wonder if you have a particularly sensitive nose for rancid compounds?

My understanding is that the very long cooking times for stock (up to 24 hours) is intended to dissolve the minerals such as calcium out of the bones. I do not rely on stock for my calcium.

If you are only interested in extracting gelatin from the bones and connective tissue a shorter cooking time of more like 5-7 hours should be sufficient. I have even made ham hock stew in only two hours and extracted enough gelatin that the stew will set solid when chilled in the fridge.

47a42b6be94caf700fce9509e38bb6a4

(9647)

on October 25, 2011
at 06:58 AM

@Matthew, Rockgrrl, Kent. What about: cooking on the stove versus cooking in a slow-cooker? My slow cooker seems to do a pretty good job of sealing off its contents from the air; that's why it works so well, right? Because the heat is sealed in there? Is this a negligible distinction as far as oxygen is concerned though? Somehow I suspect Matthew might have some ideas about this. I would research it myself but I've had too much to drink.

32f5749fa6cf7adbeb0b0b031ba82b46

(41747)

on October 28, 2011
at 03:05 PM

Paul, it doesn't take much oxygen to do significant oxidation.

2
2c4b2d9c824982cf26bddb4cc1d65069

on October 12, 2011
at 03:30 PM

I made a 24 hr bone broth a couple of weeks ago and it was awful! I have no idea why..but I plan on looking into it. I cooked it in a crock pot.

1
Fbf1685f14581c97b008a734f68cfe57

on December 30, 2011
at 04:13 PM

The funny smell is likely due to compounds in the organ meats breaking down after a long simmer. Better to leave the liver out of the broth as it occasionally gives off a truly funky smell to the entire pot. Can also become bitter.

1
Bad3a78e228c67a7513c28f17c36b3cf

(1387)

on October 28, 2011
at 02:19 PM

I don't think the fat goes rancid, but depending on the bones you use, it might indeed stink. In my experience meaty marrow bones = stinky broth. The best tasting beef broth IMO (though perhaps not the most nutritious) is made from the neck or tail--lots of cartilage and fat but not much bone or marrow. Just made some the other day in my big crock pot with oxtail pieces. Cooked about 20 hours. Result smelled awesome.

1
Ca1150430b1904659742ce2cad621c7d

(12540)

on October 28, 2011
at 02:02 PM

I only use bones, vinegar, and salt in my bone broth, and never have had a problem with the fat going rancid. In fact, I use the raised beef fat from the first pot for cooking. However, there is a smell that comes with cooking bones or rendering fat that is... distinct. Some folk find it mighty unpleasant, though it doesn't really bother me. My mate says it smells "rancid' to her -- but we figured out quickly that she has that same reaction even when I'm rendering lard or crisping chicken skins, so it's the long cooking of the fat at low temps that brings it out, I guess.

I use a stovetop for my stock, and a larte, stainless, French-style heavy stock pot. I usually keep the same large beef bones going for several days (though I get the most tallow on the first couple of days). I cook for 24-36 hours, strain, put the bones back in the stockpot, add more water and vinegar, and start 'em all over again. Never had an issue with rancidity in the tallow I collect.

0
4886d3390cb1de913ecc198e72cc072c

on April 05, 2012
at 06:19 PM

How long can bone broth be refrigerate before going bad?

0
E3d70aeba50c3b761ddd88512db8a971

(65)

on April 05, 2012
at 04:04 PM

Sometimes, when my broth is heading towards 30+ hours of simmering (with lid), it gets all rainbow coloury. Looks almost like i've put some dish wash in there (without the foam though). Does anyone know why this is and/or do you recognize it?

-1
1636296bc92c684c8a91b2426d1ad11a

on January 15, 2012
at 04:32 AM

As a student in the culenary arts i can speak from an educated position on this. First of all you need to be skimming your stock regularly while cooking. Second the industry standard is 4-6 hours min. Heers another thing are you cooling youre stock rapidly? If not your stock is now a giant petrie dish breeding germs you need to put your pot in a sink of ice water and rapid cool it. Between certain temps germs can grow if you put ur pot in an ice bath and fridge it right away this wont happen. (i dnt remember the exact temps between 70 and something). This will stop any rancidity. Also germs cant breed between the 2 temps so while at a simmer germs wont invade they will however soon as you change the temp dramatically .

32f5749fa6cf7adbeb0b0b031ba82b46

(41747)

on January 15, 2012
at 01:59 PM

Rancidity does not refer to bacterial growth. It's refers to the chemical degradation of the components, specifically we're talking about degradation/oxidation of the fat.

32f5749fa6cf7adbeb0b0b031ba82b46

(41747)

on January 15, 2012
at 02:00 PM

Either way, I'd anticipate that after 6-36 hours of simmer time, the stock is pretty sterile.

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