Is there a safety reason or is this just leftover nonsense from the low-fat "health" camp of the past 2 decades?

No it isn't left-over nonsense, sorry. :)

There are several good reasons that are safety related. Now obviously you won't be able to remove it all even when using the overnight chilling method before skimming. A small amount will remain but the majority should be removed..

First, it affects the density and the processing time recommended is based on skimmed broth. Additional time would be required. How much is unknown.

Second, it results in a poor seal on the jars which leads to possible contamination, bacterial and fungal growth, rancidity, etc. even without the signs of full seal failure. It has reduced shelf life.

Third, and most important, the fat insulates any bacteria in the broth and prevents the heat from penetrating it and killing it.

There are more considerations but that covers the main ones.

Hope that helps.

Dave

Edited to add that you can always freeze the removed fats if you wish - takes up much less freezer space - and then you could add them back to the broth at use.

This post was edited by digdirt on Fri, Feb 14, 14 at 19:05

Thank you Dave! I suspected it might be something safety related, which is why I asked, but I wanted to be sure.

Sometimes, you know, things like "skim the fat" get passed on just because that's what "everyone" is doing and people just assume that's what everyone else wants too.

So I will skim for my pressure-canning. Do you think it's still okay to add the vinegar, chicken feet, and herbs? I am thinking the chicken feet and vinegar might be wasted here though, because likely the long intense pressure-canning will break down any gelatin that forms anyway (over-boiling will do that).

Thoughts?

Do you think it's still okay to add the vinegar, chicken feet, and herbs? I am thinking the chicken feet and vinegar might be wasted

Agree it would be wasted and that the gel would break down.

Personally I can't imagine adding either to good broth. The vinegar would change the flavor and the feet are a primary source of bacterial contaminants. But I don't know of any other reason why you couldn't if you wanted as long as the feet are removed before canning.

Dave

Intetesting thread, learning a lot! Right now i tend to make broth in a stainless steel pressure cooker. Last night a big grassfed beef knuckle produced great gelatin after about 2 hours in the cooker. Holiday turkey carcass is done in less than an hour, and it makes great gelatin too.

If i skim fat, i use one of thse bottom pouring measuring cups, through a fine wire sieve straight into a pint widemouth jar, then freeze. So, i could instead seal this and then pressure can it? Do you think it would ruin the nice jiggly stocks i am getting?

Sometimes i do not skim the fat before freezing. Then, i will pick out the risen fat for browning meat or sauteeing onions, or whatever step 1 is for the dish that will be using the broth.

Chicken feet are a traditional stock ingredient in many cultures; Italian particularly. Apart from the nutritional benefits attributed to gelatinous broths, the sauces made from these stocks are velvety.

Vinegar, like lemon juice, brightens stocks. The trick is to not use too much. Moreover, in bone broths, presumably, it helps in the extraction of calcium from the bones.

Deborah

I do add a little vinegar sometimes, especially if i am working with older bones, such as a "retired" laying hen.

I think i will have to experiment to see if highly gelatinous stock obtained from pressure cooking loses its jiggle after pressure canning. For now i usually keep about a dozen jars in rotation in the freezer as good "stock options" come up. But, if i ever take the plunge on 1/4 of beef, i will need to adjust my strategy.

Interesting that pressure cooking will produce gelatin. It seems that my broths only gel if I don't overcook or overboil. I've never tried pressure cooking broth. I have an old presto cooker but I think I've only ever used it once in 20 years. What is involved in pressure cooking broth? How do you do it?

jenswrens- just to clarify it is the inclusion of the bones in the pressure cooking process that produces the gel. Doesn't happen with broth alone.

Cooking times:

Beef bones @ 15lbs. covered with water for 45 mins. (vs. 3-4 hours in regular pot.

Pork bones @15lbs. covered with water for 30 mins. (vs. 3-4 hours in regular pot.

Poultry bones @15 lbs. covered with water for 12-25 mins. (vs. 45 mins in regular pot)

Dave

Thanks for those times, Dave! I let a turkey frame go about 30 mins, but a big heritage turkey might benefit from a little more time than a typical commercial fryer chicken i suppose. Honestly i pay better attention to pressure cooking precision timing with veggies.

I will assume that is starting from unfrozen meat?

I went longer on my beef bones because i started with a big frozen beef knuckle and did not bother to thaw. Most of the cartilage melted down, but i had about a half cup that remained in big translucent blobs. Those were diced up with the meat and greatly added to the richness without the fat.

I have not done the math to compare cost of electric crock pot vs gas range with pressure cooker. In any case i really ought to thaw before pressure cooking to save the fuel! I do not start with frozen meat in a crock pot..too long in the danger zone temps, though that might not be as much a concern since the newer crockpots seem much hotter than the originals. I do not take that risk though..

Yeah those times are with thawed meat and don't really take into consideration volume of meat used so I tend to use them as minimum times when the volume is large. But then I am also going to can (not freeze) the resulting broth so mine would be double processed anyway and exact cooking time isn't as vital.

Dave

So now I'm confused... :)

For my broth/stock, I put in a whole chicken (the whole thing intact - bones, feet, meat, etc - no head or organs tho, haha), onion, celery, peppercorns, vinegar, thyme, parsley, salt. Then I bring to boil on the stove and simmer several hours. Strain. As it cools, it gels. Then I use or freeze. This is what I plan to now pressure can.

So if I pressure cook, I just add water and bones and nothing else? Or can I pressure cook the whole recipe above?

I have pressure cooked meat and bones for broth both with and without accompanying veggies and spice. Just depends on planned uses and my mood i guess!

If your usual recipe is safe to simmer and then pressure-can, (as long as the fat is skimmed for the safety reasons cited up top) i do not understand why it would be any better or worse to pressure cook instead of simmer.

It seems the only issue might be the doubling up of pressure time in both cooking and canning might break the gelatin down.

Canning gurus, does this sound right?

No no - I don't keep any of that stuff for the broth! It all gets strained away. But I do take the good meat off the bones after it has simmered a while, and save the meat for soups, chicken salad, etc. The rest gets tossed in the compost, and I'm left with a clear tasty broth that usually gels.

But you've added another twist with the info from the NCHFP. :-) It sounds like for their stock, they are keeping the liquid and advising adding the meat bits into the canning jars too! Even more interesting!

I pressure can with my All-American pressure canner. I have a little presto pressure cooker, but I've never really pressure cooked anything. I've always thought it was too scary. I guess I heard my grandmother tell too many stories of exploding pots. Lol.

I've linked the BBB recipe for my broth below. It says to use a whole chicken. (Well, it says "whole chicken cut up," but I'm lazy so I just dump the whole shebang in there and when it falls apart I know it's done.) I've done it both ways - with the whole chicken, and then also using just a leftover carcass and bones. The whole chicken always gives me a richer, tastier broth, IMO.

Thank you, all! You have been so helpful, and I am learning a lot!

bdot_z9_ca, if you do that experiment, please let us know if your broth still gels after double-processing. :-)

Here is a link that might be useful: Ball BB Chicken Broth Recipe

bdot_z9_ca said: If your usual recipe is safe to simmer and then pressure-can, (as long as the fat is skimmed for the safety reasons cited up top) i do not understand why it would be any better or worse to pressure cook instead of simmer.

I guess I was just wondering if the pressure cooking would help me get more consistent gelling results (as you stated you get). Sometimes my broth doesn't gel, and that makes me sad.

I was wondering the same thing, how much meat was allowable in the NCHFP "stock", since they do mention adding the meat to the jars, but processing time was much shorter than the Ball Chicken Soup recipe. I emailed Dr. Andress at the beginning of Nov, here is her reply - basically no meat should be on the carcass, only the little scraps could be added to the jars but she really advocates NO meat at all. If you want to can meat in the broth, you should follow the BBB Chicken Soup recipe (as Dave pointed out to me then), or the meat processing instructions on NCHFP website, as Dr. Andress recommends in her reply.

"

Those directions have their origins in the historic USDA procedures. There are no volume guidelines for the amount of meat. I really cannot put a quantity on the meat since there has been no testing to support what we could offer. The process is intended, however, to be for broth or stock, not significant meat or significantly sized pieces of meat and broth. It just allows you to pick the carcass some after it has been simmered to flavor the water/broth. There should only be little bits of meat left on the bones and included in the jars.

It is important to realize it is called Broth or Stock and if you think of those you buy, there are not identifiable pieces of meat in them. If it's a partial meat pack, you should use the meat process.

Here is how we re-worded it for our University of Georgia So Easy to Preserve book, below, although it's not a lot more specific. And I might now choose to say "Place large carcass bones (with as much meat removed as you can)": Or the other option is to not allow picking of the carcass at all. The directions really only allow for adding back the bits still clinging to the bones after cooling, not the all the meat stripped from the bones. So that's how we tried to word the order of actions for our book. But we can consider rewording on the website from the USDA guidelines, also. Thank you for pointing this out."

Sorry if I already posted this back in Nov.

Thank you, ajsmama, for that clarifying info. Don't be sorry for reposting! I wasn't reading back in Nov, and it definitely clears some things up for me.

No meat - just broth. Got it. And they should definitely reword it on that site.

Yep that is the clue to how much meat - the directions call for using carcasses only. A carcass has minimal meat on it.

I guess I was just wondering if the pressure cooking would help me get more consistent gelling results (as you stated you get). Sometimes my broth doesn't gel, and that makes me sad.

No, the method of cooking doesn't determine the gelling result. It is the access to the bones during the cooking that does that. Using a whole chicken means much longer cooking times to create gel as there is very limited access to the bones while cooking.

If stock is the goal then you really do need to at least cut up the chicken for the best results. The more exposed bone there is the greater the gel and the shorter the cooking time and energy required.

Dave

Glad I could help - I was confused too, that's why I emailed Dr. Andress for clarification. As I said back in Nov, my dad can carve/pick a carcass as clean as a vulture, but when we carve a turkey or chicken there's still quite a bit of meat on the bones (esp. chicken wings - we don't even bother to serve those) so what ends up in the bottom of the pot is actually a good amount of meat. I cook it all day, so there is really no meat left on the bones, it all falls off and the bones end up in tiny pieces too. But it gels really well.

Making soup for eating that night (and the next 3 days LOL) isn't the same as making stock for canning, though, as Dave points out. I did make turkey soup after Thanksgiving and again in January, and made chicken soup last week with some drumsticks I had in the freezer (not as good)). But I still haven't canned any - we just tend to stick it in the fridge and eat it.

Thank you, bdot_z9_ca, for introducing me to pressure-cooked broth! Amazing!

Yesterday I pressure cooked my second batch of beef stock (using very meaty soup bones from the local grassfed cow we purchased last year). Both batches came out perfect, and gelled like magic. The stock was super potent too. Stock I made a few months ago (from the same cow) on the stovetop was dilute and flavorless and didn't gel.

Also amazing was the fact that I started with 6 cups of water, and after it was done, I ended up with almost exactly the same amount of broth. On the stovetop, to get the same flavor, it cooks down and a lot of it evaporates away so I'm left with much less than I start with.

I am a PC broth convert - no more stovetop broth for me!

PS. I am going to can this batch today, and then I'll be able to see if it will re-gel after the pressure-canning.

now that i have a p.c., i will can broth. thanks, dave, for posting the presser cooker times for broths. i noticed that NCHFP does not address pork broth. does anyone know why ? is there a taste issue? i've never made pork soup, so any recipe suggestions if it needs to be treated differently from chicken or beef soup will be appreciated !

Good question! I've used the broth from PCing a ham in soup before, still haven't canned any stocks/broths (that might change after Thanskgiving this year!) but I'd think as long as you skimmed it well (after sitting in fridge) you'd be able to do it the same as beef or chicken stock. I think it's just one of those things they haven't tested since not too many people use it - beef or chicken stocks are used in more recipes (soups, sauces, etc.) than ham, hocks, or just pork (chops?) stock.

Worst case I'd use the seafood stock processing time. NCHFP doesn't have one, but Putting Food By (fifth edition dated 2010) says do clam or shrimp broth for 20 minutes @ 10 psi in HALF PINTS only (beef, veal, lamb, poultry is 20 min for pints or quarts). Half pints would probably be fine for ham or pork broth since it's so strongly flavored, you wouldn't use it as a base for soup like chicken or beef broth. Oh, and under meats PFB says to make sure to skim the frothy gray stuff while it's cooking.

Here is a link that might be useful: Serious Eats pork stock discussion

This post was edited by ajsmama on Thu, Nov 13, 14 at 9:59

that's a good link for info. i regret not getting the bones when i bought half a pig ! more from the queen of questions : what exactly is wrong with the froth/scum ? my guess is it's just the ick factor, not the safety issue.
another one is about the NCHFP recipe for canning chicken or rabbit. the canning time is less with bones in ! are they less dense than meat ? i found that interesting. and it seems canning a roasted chicken with bones in, in hot water, would naturally turn it into bone broth !

PFB says the froth is from protein. I don't know if it's for appearances, but I would think their main focus is safety so I'm guessing either the concentrated protein would increase the processing time, the froth traps air (which we try to eliminate in canned low-acid foods especially), or that it gives a weird flavor after processing/shelf storage?

I know chefs just recommend skimming it b/c it makes the stock cloudy. So it could just be for aesthetics, though the wording in PFB made me think it was for safety ("skim carefully to remove the gray protein froth that will collect").

Maybe Dave or another MFP knows.

does anyone know about how many quarts of broth is made from a 20# turkey carcass? and if you use a quart of canned broth to make soup, do you use it neat or diluted with water ?
happy T-day everyone ! pat

Hi pattypan,

I don't really know that there is a set amount that a certain size turkey carcass will make. I just made broth today, and FILLED a 10qt pot with the bones, aromatics and water, so I figure I will probably net about 7-8 quarts of stock after it is strained. Others may have different guidelines, but honestly, I just max out my stockpot or electric roaster capacity (depending on how many bones I have)

I usually use the broth as is in soup. It depends on the recipe you are using, but it definitely doesn't have to be diluted.

Hope this helps!

Agree there is no pre-determined amount. It all depends on what all other stuff you add, how much you cook it down, how fatty/juicy the specific bird is, how much meat you left on the carcass, etc.etc.

As for how to use it - that is a personal preference. With some things it is diluted, with some things its used straight.

Sorry but no set answers to your questions.

Dave

i just canned broth from two 20# turkey carcasses and got 11 qts. so i'm in your ballpark. the fat on top stayed semi-liquid in the fridge and took a while to remove. i'm happy i did this, but there is a lot of turkey in the freezer !

Gelling does NOT just come from bones. Certain parts of none bone items gel. Do you know what "Cow Hide Glue" is: It is made from "Cow Hide" obviously. It is just concentrated protein. Cow feet, chicken feet.. are rich in that kind of gelling protein. Bone marrow also is the same. Bone itself is the source of calcium, not protein.

About removing fat:

If you cook, boil, simmer chicken for hours and then can the liquid part (including some fat) right away, how does this can prevent heat penetration and possibly some bacteria can survive ??? Beat me.

Actually a layer of lard (Animal fat) is a sealant and would prevent the air (along with bacterial) to get in. What make a seal (Some negative pressure) is due to the water vapor in the head space that is condensed, causing a negative pressure. If you have been boiling, say some both and now fill your jar with it and immediately put the lid on it and tighten the ring it will seal perfectly.

Anyway, if I wanted to can broth, I would skim the fat for health reason (cholesterol !!!) not safety reason. YMMV

Seysonn

you're right about how a seal forms. but as i believe i've mentioned before, unless you're cooking and jarring in a laminar flow hood (aseptic environment), you're method would seal IN any floating microbe that happens to land on your ladle, funnel, lid, etc. all you have to do is wave a petri dish with medium in the air for several seconds before putting the lid on and incubating it, to see what strange stuff will grow- from the air ! the point is to kill the microbes with the lid on, then seal it in place.

If you cook, boil, simmer chicken for hours and then can the liquid part (including some fat) right away, how does this can prevent heat penetration and possibly some bacteria can survive ???

Simple. Boiling temps, even when done for hours, doesn't kill all bacteria and spores. It only destroys any toxins they may have produced up to that point. Anyone who has ever had to sterilize something knows that higher temps are required to kill the bacterial spores themselves.

And, even in suspension, fat molecules adhere to bacterial spores and retard or prevent heat penetration.

Dave

I made turkey stock on Saturday and was unable to can it the next day. I plan on skimming off the fat before I pressure can the stock and I used an approved recipe for the stock. I was wondering how long the stock can last in the fridge before I get a chance to can it. If I made it Saturday and can it by next Saturday (7 days) is it still good and safe? Or should I just freeze what I made?

Just freeze it. Normally 24 hours of refrigeration is the recommended maximum length of time between prep and canning. Even when refrigerated bacteria still develop, grow, and produce toxins. In low acid foods that is especially common.

Dave