Fat-Sealed Canning

Does anybody have any experience doing 'canning' using a layer of saturated fat [Coconut Oil seems like the reasonably healthy oil least likely to taint the flavor of something like canned fruit, though Tallow is likely the best option for savory dishes] floating on top of the solution to harden into the seal?

The idea of using plastic-lined lids disgusts me, and I'm not exactly a fan of buying disposable canning lids over and over either. This strikes me as a viable alternative [one my grandmother confirmed when I mentioned it to her] but one I'd like to discuss with the Permies community [because you guys are awesome.]

Grandma always used (and reused) wax for jams and jellies.

She did use fat for meat (potted email) stored in the cellar (almost fridge cold). Never did it for LONG term.

There also are reusable canning lids, Tattler is one brand but I can't remember the others.

I am familiar with the Tattler lids. They're made of plastic and some of the people I know who use them report uncomfortable failure rates rising over the course of numerous uses.

That's why love the idea of exploring a layer of Saturated Fat for the seal. Coconut Oil for over things like canned peaches or cherries or plums or sweet sauces, Tallow for things like soups or savory sauces.

Wax and fat sealing jars and pots pre-dates canning. Wax and fat 'breath' as in they allow the exchange of air between the food and the...um...air.

I haven't much experience with petroleum based wax (which is most common and what some of my friends use for their jams), so I don't know how much it can be said to breath. Let's assume that we are talking about the kinds of waxes and fats available pre-1800 ish.

This kind of sealing works very well with pre-industrial preservation techniques. Basically, for most of human existence, the idea of a vacuum was impossible to fathom. Airlocks were seldom employed and imperfect when they were. Food was considered a living thing and required air to maintain its goodness. Actual 'sealing' of food with wax, bladders (yes, actual animal bladders), &c. all let the food breath a little over time. The cook created an environment that encouraged beneficial invisible beasties to preserve the food - we call this probiotic bacteria, yeast, &c - and discouraged invisible beasties that spoiled food. Also, these preserved foods would be kept in the larder, or other cool part of the house, usually underground. About 10 degrees C at a guess.

With the invention of canning as a food preservation method, we found a way to remove (nearly) all bacteria, yeast, and other invisible beasties from the food before sealing it in the can/jar. This removed both the good and bad invisible beasties. If this food 'breaths' then we don't know what sort of invisible beasties might enter into the food, so it's vital that can foods are in a situation that does not breath.

What does this mean for wax and food preservation?

I personally avoid wax, oil, fats for modern food preservation. If I'm sterilizing the food, I use the modern canning equipment and lids. If I'm making a pre-industrial food, like a fermented food or a food with suffecent acid/sugar/salt in it to prevent unwanted invisible beasties, I'll use wax or fat.

Perhaps the solution away from plastic and lids that we have to buy each time we can, is to move away from canning? It's just a thought, and it totally depends on your own situation and desires. Wild Fermentation by Katz is a good starting point for learning about traditional preservation techniques that actually work.

I like this book for its compendium of traditional food preservation techniques. Are they all safe? The anecdotal evidence of what grandma did is not persuasive. In pre-industrial times, there were no public health data, and outbreaks of botulism and listeria were contained within a very small sphere of pain. But not enough people got sick to motivate change. I am of the strong belief that the industrial food chain introduces as many risks as it ameliorates. And the USDA guidelines are much stricter than in other countries for home canning, a sign of our culture that is risk-averse and worships the ideal of scientific progress. Read some 1950s cookbooks to see what I mean. The thing that scares me is reading some very crazy hat stuff people say is safe because they read it on the Internet. Let's be the solution here - you really have to be willing to assess your own risks if you don't follow a well-tested method.

Would I pack food with a fat seal? Probably something like goose rillettes, a centuries-old traditional French food, if I had a proper root cellar that mimicked what grand-mere had. I do not, so I don't. I would not in a million years put a layer of fat over a salsa and call it good, unless it were in the freezer. A chacun son goût, each to his own taste, as maman would say.

R Ranson wrote:Wax and fat sealing jars and pots pre-dates canning. Wax and fat 'breath' as in they allow the exchange of air between the food and the...um...air.

If this is true, then why does only the top of a jar of tallow begin to go rancid? The deeper layers remain pristine over time.

It seems to me like a paper thin layer might 'breath' but that nothing should be penetrating say... an inch thick layer of solidified tallow or coconut oil.

This is the same basic premise that allows confit to last so long, because nothing penetrates deeply into the hardened fat.

Or am I mistaken?

Perhaps the solution away from plastic and lids that we have to buy each time we can, is to move away from canning? It's just a thought, and it totally depends on your own situation and desires. Wild Fermentation by Katz is a good starting point for learning about traditional preservation techniques that actually work.

Unlike the people who seem to want to can everything under the sun, I try to take a balanced approach. Canned stonefruit is ridiculously good, it's also a means of preserving that harvest in an alternative manner to dehydration [which I also like, but diversity is something that appeals to me.]

Same goes for many sauces, far easier to make a big pot and can the surplus than to dehydrate the ingredients and make the sauce fresh every time it's to be used.

I'm with Ann, and the value of personal responsibility. I can oodles of foods. I test for pH, for sugar content, salt content.

I'm an independent thinker, afflicted with a high opinion of my own judgement and opinions, doing my own risk management.

Years ago, I knew an old Native American woman who said as a child their family would kill a pig in the fall, grind a lot into sausage, cook the sausage, pack it in a crock of some kind, pour the fat over the meat to cover it. Throughout the winter they pulled meat out of the crock. She told me she could remember sneaking sausage out to eat. It sounded like a fat sealed method of food preservation, and a high risk food at that. She would have been born ~ 1910.

I've never been willing to try it myself. It seems like it might work, but they likely stored that crock in an unheated space of some kind in the near freezing conditions of winter in Oklahoma. Probably they did not finish processing that pig until well in to cold weather, and how do I know the details, the what and how of it?

Further, I pressure can chicken broth, and have the instructions (Ball's Blue Book) for solid packing meat, and have eaten home canned tuna and salmon, (and lived to tell the tale)!

I have rendered tallow and used commercial tallow for soapmaking.

When I imagine the pressurized and sterilized foods in the glass jar, with a layer of tallow on top, the problem I wonder about is the cooling process, when food bubbles and bubbles. I turn off the heat and the thing cools from the outside in. First the air in the pressure cooker cools and therefore depressurizes, then the stuff in the jars bubbles to try to fill the developing vacuum created around them by the cooling process. What a mess, fat spilling out of the jars! And I wonder will mist sized bubbles of moisture be caught in the tallow?

About whether or not tallow or coconut oil "breathe" is questionable. I would not count on it breathing or not breathing. I do know that exposed to air it will oxidize at some point. Questions arise in my mind about the rate of oxidization, the thickness of the layer of tallow, the shelf life.

About sealing jelly with parafin, a method my mother and grandmother and all the canning women of their generations practiced, they were sealing a food preserved by sugar and acid content, the parafin sealed in the moisture more than anything else.

To my mind, there are too many variables with this question. The universities are not going to research it, and I would have to risk my own health and life to do my own research. Not worth it to me, but just my take on it.

Canning is not an eons old practice. It is post industrial revolution. The methods that served humanity through the centuries are outlined in Katz' fermentation books and the link Ann provided. That's where I go for information I can count on when I want to try something new.

I realize I've done nothing here but use my own words to reiterate what Ann posted. Same song, different verse. I offer it up because it might provide perspective to those who consider sealing canned goods with a layer of fat.

Ann Torrence wrote:Would I pack food with a fat seal? Probably something like goose rillettes, a centuries-old traditional French food, if I had a proper root cellar that mimicked what grand-mere had. I do not, so I don't. I would not in a million years put a layer of fat over a salsa and call it good, unless it were in the freezer. A chacun son goût, each to his own taste, as maman would say.

Everyone has to assess their own risks and make these choices for themselves.

On the salsa subject, lets not forget that hot peppers are themselves used as a preservative in many tropical environs. If there was enough *fire* and enough acid in the salsa, I'd give it a shot. Maybe said salsa would need to be cut half and half with... say... rehydrated tomato fruit leather, but its an alternative to mixing the salsa recipe every time you want to eat salsa.

Kyrt Ryder wrote: lets not forget that hot peppers are themselves used as a preservative in many tropical environs.

Are they Kyrt? I know they're used to flavor dried things, and to mask "ripe" or "off" flavors in unpreserved "fresh" meat, but had not heard they acted as a "preservative". In salsa recipes I'm familiar with, the peppers are always counted as NOT bringing preservative actions themselves, and because they do not bring acid or significant sugar, their addition has to be balanced with acid from somewhere else to prevent the growth of Clostridium botulinum, and the formation of deadly botulinum.

In all likelihood those recipes lack the fire [or scovilles if you will] for the peppers to do any preservation. Hence my comment of the salsa perhaps being a concentrate requiring dilution with rehydrated tomato fruit leather.

But yes, I've done a great deal of research on this. Capsaicin in high enough concentrations is a very potent antimicrobial.

Garlic, hot peppers, and in fact many spices and herbs have traditionally been used to "help" prevent dangerous microbes.

In addition, soaking in fat was a traditional way that colonists stored meat. I think we have to think about all the factors. I like history and I find it fascinating, but I tread lightly when I think about feeding it to my family. THere had to be lots of secrets and procedures that "worked" and perhaps they didn't know why. People died much more frequently and for more unknown reasons in those days. Meat on your farm could be raised reasonably inexpensively, but buying it in a restaurant? If I wanted to store meat in fat, I would really want to do research, find out how people really did it with all the details, and find out as much as I can first.
John S
PDX OR

(Edit to add: Of course you need to take responsibility for your food safety. Our ancestors knew how to evaluate food and use these techniques. We no longer have skill set or knowledge base. When in doubt, toss it out.)

Interesting thing about Botulism - it dosen't like air. Wasn't much of an issue pre-canning. When canning foods, one needs to be extra aware of botulism and the like. There are a few good resorses out there on canning safety but I haven't found one I trust, yet, that tackles canning with fat.





A really neat overview of Botulism in fermented foods and why we don't need to worry

If this is true, then why does only the top of a jar of tallow begin to go rancid? The deeper layers remain pristine over time.

Over time... this is the key. The top layer goes rancid first because it's most exposed to air. It's harder for the air to penetrate further down, thus it takes longer to go rancid, but it does ... over time. Depending on the way it's stored, and what it's stored in, and the temperature it's stored at, it can take months, years or decades for the whole thing to go rancid.



My own point of view, canning is a useful tool in the kitchen. Mostly, however, I use it for taste and texture. I don't like to use canning a lot because... well, the lids are single use only, and I don't trust the safety of it. PH testing, bla bla bla...So many things we need to take into account and it can be risky to use a recipe that isn't 'approved' for canning. It's such a relatively new method of preserving food - not really part of the kitchen until the 1920s, and not fully integrating into daily life until after WWII (then again, neither did the fridge). A lot of the other methods are tried and true, thousand year's of history behind them. It's very much a matter of trust for me.

But back to the fat.

Years ago, I knew an old Native American woman who said as a child their family would kill a pig in the fall, grind a lot into sausage, cook the sausage, pack it in a crock of some kind, pour the fat over the meat to cover it. Throughout the winter they pulled meat out of the crock. She told me she could remember sneaking sausage out to eat. It sounded like a fat sealed method of food preservation, and a high risk food at that.

I've seen this recently in a book. Can't remember the exact book, but it was while I was reading up on mennonite cooking.

I suspect the sausages would have a high salt content, possibly saltpeter. Cooking them in fat like rolletts would make a lot of sense, as it helps to replace the 'water' in the meat with fat, which goes 'off' slower. Or, instead of using the fat as the preservation technique, it could be used to prevent drying out of the sausage, while it ferments as a way of storing it. I've seen recipes for both ways.

The book In the Charcuterie, has some wonderful bits about preserving meat in fat. Well worth a read for those interested.

In the meantime, I think I'll snuggle up with some hot cocoa and Mrs Beeton's Book of Household Management. If I remember right, there is a lot in there about storing foods in fats and oils.

R Ranson wrote:Interesting thing about Botulism - it dosen't like air.

Or acid.

More anecdotal info, apparently you can reuse canning lids if you don't mind the occasional one failing in the process. My neighbor dates hers with the year, she just tossed all hers from the 2000s, but is using them at least 4 years old, based on a jar she gave me. Sealed is sealed, in my book.

If I could afford it, I'd replace all with Weck jars. Me and Martha S. That'd be the life.

I re-use my lids. I inspect for flaws of any kind in the "finish" on the food side of them, and I inspect the sealing material as well.

I inspect the brand new lids just as carefully. They aren't perfect all the time either. (more of the "I'll decide for myself" attitude)

Lack of consensus is strong enough this demands experimentation.

I'll start with an item relatively safe. This summer I'll be buying some bulk stone fruit [whatever's the best deal at the time, cherries, peaches, plums....] and 'canning' twenty-four jars with a layer of coconut oil on top in lieu of the lid, and an additional twelve jars with the lid instead of the coconut oil.

All jars get stuffed into the 'root cellar' [concrete thermal regulated storage room we have that never gets over 65 degrees in the dog days of summer] and each month sees the use of two jars of fat-sealed and one lidded jar as a comparison.

This only needs to last one year, from harvest to harvest.

I'm glad you are going to use a relatively safe/high sugar and acid food for your experiment. Will you feed some to the chickens or other living creatures before you eat it?

I'm not sure. Certainly my nose is going to be the first indicator, comparing the conventionally canned to the fat-sealed. Then a tentative taste to see if they taste the same.

Being honest, most creatures that should eat something like canned fruit [poultry, pigs...] really wouldn't care and tend to be far tougher than human beings anyway when it comes to dangerous food.

There might be some additional information in this thread: preserving meat in a crock of lard/fat

I've seen historical accounts of fermented fruits and veg sealed with fat/wax/oil. I've even tried it with some ferments... with mixed results.

I'm curious how sterilized fruits will act in the same situation. My main historical research into food and cooking, lies long before canning appears, so I don't know as much about it as I would like. I haven't found any resources that say this would work one way or another... except for the standard disclaimer that comes with the canning equipment.

Please let us know how it goes.

I have also seen somewhere a historical account of "fresh" whole eggs being packed in a wooden barrel that was then filled with lard, prior to the whole thing being loaded in a wagon for transport to the American west during the California gold rush. Since whole eggs keep well anyway and keep better when the shells are waxed or sealed against oxygen, that makes sense to me. But at least when an egg goes bad nobody's in any doubt.

Interesting on the eggs. There's often advice to coat them in mineral oil or similar for long term storage, it stands to reason fat should yield similar results.

R Ranson wrote:Please let us know how it goes.

I was planning to give the experiment its own thread when I start it.

The insidious thing about botulism is you can't smell it.

So, if you do this experiment, please use an acidic food!

My husband once placed a jar of fresh pesto (from Costco) in the cabinet instead of the fridge. He (much) later pulled it out, opened it and dumped it on a pot of pasta. Only as he did this did he realize the jar had been pressurized and went FFffft when he opened it. He remembered you shouldn't eat such a thing, walked to the chicken pen with the pot and dumped it on the (heavily mulched) ground.

The chickens ate only the pasta without any sauce. I ran out there when I heard the tale, worried he had poisoned our chickens, but they knew better. We couldn't smell any difference, but I think the hens could! Over time, with a few rains, all the pesto washed into the mulch and the hens ate the pasta.

I can't remember the numbers, but a certain number of people die every year in Italy from eating traditional mostly-safe foods that happened to grow clostridium botulinum. The risk is rare, but real. It all depends on your comfort with risk.

Botulism is one problem I'm not actually worried about.

Anything I do this with is either going to be too acidic for Botulism to reproduce in, or will have been cooked to the appropriate temperature [and measured for verification] so as to kill off the spores.

Additional spores are not going to be able to get in through the fat layer.

EDIT: that is very interesting about the chickens though. It's making me rethink my hesitation to trust livestock to care about whether or not something's gone wrong.

The melting point of coconut oil is somewhere around 77 F. Therefore, if coconut oil is used to seal a jar, the oil is going to be liquid for a long time after the jars are cool enough to sustain the growth of yeast. My prediction of the outcome of this experiment is that natural yeasts will fall onto the oil, and migrate through the liquid oil to the solution, and that they will cause the fruits to ferment into wine.

That's an interesting prediction Joseph. I try not to drink a whole lot of alcohol, but if I were to drink homemade is what I would choose.

Having slept on this thread, I realize that I'm not fully comfortable with using oil and fats as a substitute for a lid in a canning situation. Or more specifically, with recommending the attempt.

Sealing with fat and oil works in a traditional setting... it has no guarantee of working with a pasteurized food like we get with canning. Not only is the method very different (ferment vs pasteurized) the modern day ingredients are drastically different too. Carrots are ORANGE! It's just one small food change, but an example of how we take all these new food crazes for granted. Does anyone here remember the time when there was no white cauliflower? It's still living history. Not these 'speciality' cauliflower either, actual, every day cauliflower not being white. This change in our ingredients is one of the biggest difficulties with recreating historical cooking - not only are carrots a funny colour now, if we boil them for 2 to 5 hours, they aren't crisp-tender (like they would have been circa 1850), but instead turn to mush.

I'm pointing this out not to put you off. Permies seems to be about challenging what we take for granted as working or not working. I just worry about a passer by coming to this thread and thinking - great, it works, I'll can some tuna with coconut oil top, no problem. The guys here said it's fine.



I want to stress caution to the casual reader who pops by this forum. This isn't a tried method (yet). It's more in the brainstorm phase - which includes brainstorming good and bad possible outcomes.

It might work. We aren't going to find out just sitting around chinwagging on the internet. The only way to find out is doing, so it's great that we have a willing volunteer to do trials for us.

About botulism, I'm "pretty sure" it is as toxic to chickens and pigs as it is to humans and other vertebrates. It is a neurotoxin, and paralyzes, the respiratory system (the organism stops breathing). The death rate has decreased in recent years through early identification, and putting the patient on a ventilator so they continue to live while the toxins are removed and possibly metabolized by the organism.

About animals not eating tainted food,
I knew a woman once who tried fermenting the kitchen waste she fed her chickens. Many of them died, she thought they had botulism, and held them in her lap and gave them water. Some of them survived, but I wondered about the accuracy of her diagnosis.

Not all experiments go as we expect. That's why I'm glad you are trying a very low risk food, if you do in fact decide to do it next summer. I was not thinking of fermentation to alcohol as a likely outcome. I was thinking you might find a nice blue green mold growing between the fat and the jelly/fruit.

Thekla McDaniels wrote:Not all experiments go as we expect. That's why I'm glad you are trying a very low risk food, if you do in fact decide to do it next summer. I was not thinking of fermentation to alcohol as a likely outcome. I was thinking you might find a nice blue green mold growing between the fat and the jelly/fruit.

That may be, though I suspect there won't be enough oxygen to support the growth of that mold under an inch of saturated fat.

yeah, and I did not mean there would be mold in all of them. It's important to keep in mind that for MANY life forms, oxygen is not required. Life forms grow in all conditions. The deepest depths of the ocean, miles beneath the earth's surface, in the boiling waters of Yellowstone's geothermal waters, in the brines of the Great Salt Lake, Mono Lake, and the Dead Sea. Life is an opportunist and plenty of organisms are facultative anaerobes- they can live without O2 if they have to.

I'm not telling you not to try it. I just want to know you know of every danger that I am aware of. I feel responsible to share information with you if it appears to me that you are counting on something I know may not be accurate or worthy of your trust/confidence.

Sorry if I seem like a know it all.

No worries, your concern and advice is greatly appreciated

It's an experiment for a reason, because this sort of thing is unproven. Depending on my results, 2017 may see an experiment with Soups/Sauces and tallow. Likely sheep Tallow because it hardens at a higher temperature than beef.

I think it was called meat potting or potted meat. Usually done after butchering a hog.
Blog where they tried it. http://hillsidehomestead.com/2013/03/10/pork-preservation-success/

Kathleen Scott wrote:I think it was called meat potting or potted meat. Usually done after butchering a hog.
Blog where they tried it. http://hillsidehomestead.com/2013/03/10/pork-preservation-success/

From that link...

Packing meat in lard is a very old food preservation technique. This meat will stay good as long as they lard is cold and firm down in the cellar, i.e. probably till May

Hmmm, Tallow [especially Sheep Tallow] remains hard at much higher temperatures than lard. Certainly something for future experiments of the Fruit Canning experiment goes well.

Re: eggs in lard.

That was done as packing material more than anything, to keep from breaking all the eggs in transport. And they needed lard, so it was separated out and used when they got there.

Green packaging is an old idea!

When comparing tallow to lard, the difference in melting/ hardening temperature is not the only difference. The lard is a softer fat, while tallow is much more brittle. This might make one a better sealant than the other. When I think of retrieving something from the lard or tallow, I think possibly cracking the tallow, and the crack becoming a venue for the entry of microorganisms deeper into the container. Then I think, "well if every piece in there was surrounded by the fat, rather than the fat just providing a layer on top"
My mental picture of the fat sealed food thus far has been fat on top and meat and juices below, kind of like what happens if you simmer a whole chicken or chicken bones, then turn the fire off and let it cool. I get a jelly-bone solid matrix below, and a layer of fat on top.

Dunno know if this matters. It's just another thought on this long thread.

@ Kyrt: If you're allergic to disposable canning lids, like I am, maybe French-style canning jars are your ticket? For example:

http://www.leparfait.fr/produits-le-parfait

There are many manufacturers of this kind of canning jar in France I believe. Nice glass lids that get reused forever like your jars. You're supposed to get a new rubber seal every time though. Rumor has it that some people occasionally reuse the rubber seals without causing untimely deaths. In any case, not a problem for Permies, we alter the microclimate of our homesteads to be able to grow a rubber tree and we make our own rubber seals, problem solved.

Also thought I'd mention: The Chinese preserved eggs for centuries. They were black. Ash? Don't quite remember. Here, (uncooked) cured meats are very much a local reality. And yes, even mild paprika is a very potent preservative, it revolutionized meat preservation in Spain when brought from the Americas. We also salt fish to preserve it. These preservation methods hinge on getting the water and excess humidity out and in the case of the meat, it's own fat is also said to help preserve but is not the only weapon in the arsenal, the spices (sometimes) and the salting and drying (always) are also key.

I don't foresee a good outcome to your salsa experiment, though, at least if we're thinking of the same kind of (raw, Mexican-style, fresh) salsa. Fresh vegetables are going to spoil, period. Something needs to be done. Canned salsa is cooked, nowhere as good as fresh. I supposed you could make a fermented salsa if you wanted, that might be OK with the right ingredients. Other preservation methods? Freezing, dehydrating... Why bother, I say. But a layer of fat or wax on top is not going to stop fresh salsa from spoiling, quite the contrary, I'd expect. Not to keep you from experimenting though, of course!

Regarding fat seals, coconut oil or tallow, if using as your only seal I might be concenrned about the fat contracting and coming away from the side of the jar over time with drying and temperature variations. I also wouldn't try to preserve anything that way that hadn't been thoroughly cooked.

But as always, a good culinary anthropologist could set us all straight -- people in different cultures have spent millenia solving problems like these in very innovative ways. We need to get our noses out of our 1950s industrial-prosperity-era cookbooks and education and take a look at what the rest of the world has been doing for ages and ages. Guaranteed they've already solved nearly all of our problems for us, and the solutions are sometimes really amazing! And delicious!

Dave Forrest wrote:@ Kyrt: If you're allergic to disposable canning lids, like I am, maybe French-style canning jars are your ticket? For example:

http://www.leparfait.fr/produits-le-parfait

There are many manufacturers of this kind of canning jar in France I believe. Nice glass lids that get reused forever like your jars. You're supposed to get a new rubber seal every time though. Rumor has it that some people occasionally reuse the rubber seals without causing untimely deaths. In any case, not a problem for Permies, we alter the microclimate of our homesteads to be able to grow a rubber tree and we make our own rubber seals, problem solved.

I'm familiar with them [from a distance online.] They are nice, but expensive.

As for the rubber tree, that depends heavily on location and climate. I don't forsee me being able to arrange an adequate microclimate where I am. Even if I *could* the work to results ratio of that is probably a far cry from being worthwhile.

Also thought I'd mention: The Chinese preserved eggs for centuries. They were black. Ash? Don't quite remember.

I am quite familiar with the concept of Century Eggs. It's something I'd like to experiment with at some point.

Here, (uncooked) cured meats are very much a local reality. And yes, even mild paprika is a very potent preservative, it revolutionized meat preservation in Spain when brought from the Americas. We also salt fish to preserve it. These preservation methods hinge on getting the water and excess humidity out and in the case of the meat, it's own fat is also said to help preserve but is not the only weapon in the arsenal, the spices (sometimes) and the salting and drying (always) are also key.

Very cool. Thanks for the information.

I don't foresee a good outcome to your salsa experiment, though, at least if we're thinking of the same kind of (raw, Mexican-style, fresh) salsa. Fresh vegetables are going to spoil, period. Something needs to be done. Canned salsa is cooked, nowhere as good as fresh. I supposed you could make a fermented salsa if you wanted, that might be OK with the right ingredients.

I don't actually HAVE a salsa experiment planned. At one point we were discussing the preservative properties of Capcasin and salsa came up for discussion. If you want to preserve fresh salsa the answer is Lacto-fermentation.

Regarding fat seals, coconut oil or tallow, if using as your only seal I might be concenrned about the fat contracting and coming away from the side of the jar over time with drying and temperature variations. I also wouldn't try to preserve anything that way that hadn't been thoroughly cooked.

Spo you feel that it might be wise to close a lid above the fat to prevent drying of the fat? I could get behind that.

But as always, a good culinary anthropologist could set us all straight -- people in different cultures have spent millenia solving problems like these in very innovative ways. We need to get our noses out of our 1950s industrial-prosperity-era cookbooks and education and take a look at what the rest of the world has been doing for ages and ages. Guaranteed they've already solved nearly all of our problems for us, and the solutions are sometimes really amazing! And delicious!

Sometimes I really wish I knew Italian, Latin, Chinese and Greek. But I have other priorities lol.