When (and how) did jam become "refrigerate after opening"?

If I had a bigger garden I'd probably feel differently about experimenting. For example, I only have 8 square feet of cucumbers for pickles.

I'm no expert but I do clearly remember picking all kinds of fruit and my grandmother would make jam or preserves or whatever name you want to put to it.
all she ever used was some water and sugar then would pour wax on top of jar to seal it.
the last jelly I made myself was lemon jelly and all I used was lemons water and sugar., have to make this one its just not something common, but no wax on top I used mason jar I boiled and put hot jelly in hot jar with new lids and when it cooled it sucked the lid down creating vacuum, those jars were good for 2 years, but once opened had to be refrigerated unless it was used up quickly.

how do you use the kool aid in recipies?

Sandy

What if I don't eat much jam?  Maybe a cup or two per year?

I suggest you process carefully in small jars. You can get 1/4 cup jars for processing.
Some products, with care, can be frozen.
Can't short cut safety.

I've had raspberry jam with only honey added for sweetness from a nearby organic farm store. It was amazing & I never had trouble with it molding 😃

When I was a kid, my Mom made all of our jam by boiling the fruit/sugar mix, and while quite hot, pouring it into sterilized jars and then immediately pouring a 1/2 inch layer of melted wax on top of the hot jam. The jars of jam, when cool, were placed on a cupboard shelf and left there until needed. Rarely, when the wax disk was pried off, there would be mold on the surface of the jam. This was removed by taking the top 1/2 inch of jam off with a spoon before the jam was eaten. Sometimes she would add pectin to the boil if the jam was thin - like berry jam tended to be.
Everyone is right that this is a multifactorial issue, but, as most have said, the two most important factors are sugar content (for sweetness and to give the jam/jelly a really high osmotic potential) and acid content. Pectin is just a thickener or jelling agent. Most preservation of food consists of heating the food to kill any bacteria and/or fungi, providing a high osmotic potential (mostly with sugar and/or salt), creating an acidic environment as with lemon juice (not Meyer lemons which are a lemon X orange hybrid that is low in acid - just use the bottled lemon juice to be safe) or 5% vinegar, and preventing airborne bacterial and fungal spores from recontaminating the food (cooked, salted meat while hot was placed in crocks and covered with hot oil such as lard to preserve it in the past - don't do this at home)

A couple years ago I had a huge batch of plums which I just boiled up and added some lemon juice to. I really didn't want it sweet and I called it "compote". It was in small jars and I still have a jar or three. I've given them away over the years and everyone loves the taste of the bitter plums… You don't need much.

So far I've had no complaints with mould but they were tiny jars. Although when I was a kid I remember we just scraped off the mould and kept going.   in fact that's definitely what I do now with cheese and what not. Give it a sniff and if it doesn't smell horrible then it gets eaten… So far I've never been ill.

I'm really concerned about botulism but I understand it's odorless and tasteless… I would like to know better exactly what causes it, but for the most part I assume I will die slipping down a staircase so what's the point in worrying when I have never experienced it, nor anyone I know. Nor anyone they know… I mean how often does it really raise its head?  

Sorry, I don't mean to seem callous.

Lots of changes in our food supply since I was one of the kids in a large family.  The jam never grew mold because it didn’t have time!

I made a lot of jam for my family when I had children.  If a bit of mold grew on the surface of the jam, I just lifted or scraped it off.  The surface of the jam is a different environment from the undisturbed body of the jam.  High  sugar and high acid is not going to grow botulinum, blue mold is on cheese too, and we don’t worry about it.  I wouldn’t say the same about commercially prepared food, just what I made.


This is from my grandmother’s cook book.  This was how they did it in 1935.


In those days they told you the basic process and enough for you to utilize what you had.  There are some specific recipes as well.

And this is how I learned.

The blue mold you see on jam, bread, cheese, etc. is a species of Penicillium, a fungus, whereas botulinum poisoning is caused by a species of Clostridium, a bacterium. Quite deadly, but the toxin it produces is heat labile so heating the food to boiling THROUGHOUT, THROUGHOUT, THROUGHOUT, as in THROUGH AND THROUGH, and then holding the food at boiling for at least 10 minutes will destroy the toxin and render the food non-toxic. This is why people always boil  certain categories of home-canned food.. Just to be safe. Don't eat your home canned beans cold out of the jar. You may be lucky many times, but it only takes once. As mentioned in the previous post, jam with an appropriately high sugar content and acid content, does not support the growth of Clostridium so you won't get botulinum poisoning from properly processed jam.

The "Refrigerate after opening" labelling may be an FDA requirement. The FDA also changed the safe canning suggestion to water bath canning for jams and jellies whereas hot liquid in sterilized jars was previously considered adequate.
I don't know, but since people now turn just about anything into jam/jelly - garlic, pepper, etc. - maybe safety in how jams/jellies are processed is a bigger issue. I'll never forget the account the instructor told in the food safety class about a chef who made up aioli sauce using fresh garlic and mayonnaise, but did not refrigerate it overnight. The next evening he killed 10 people who ate aioli at the restaurant by botulinum poisoning.

Thekla McDaniels wrote:

This is from my grandmother’s cook book.  This was how they did it in 1935.
And this is how I learned.

Thank for the pictures. Very interesting !

P.S.  I saw a partial recipe for currant jelly. I wish the recipe was there LOL
I don't like jams. But  I sure do like jellies. My favorite of all is black currant jelly.

About botulism:

Botulinum clostridium is a soil microorganism.  It becomes a problem when allowed a chance to grow in preserved food.  In order to grow it needs anaerobic conditions.  We provide that when we seal jars of food.  It cannot grow in an acidic environment.  I’m not sure how low a pH is required to prevent growth, one  reference says pH below 4.6.  High salinity prevents botulism growth, and for botulism to develop there also needs to be moisture.

It is a lethal toxin, and doesn’t require much to kill you.  It disrupts neurological functions (I think it disrupts the neuro pathways that provides for breathing and heartbeat).

I’m truly fearful.

So, when I can things like tomatoes I didn’t grow (plant breeding has created low acid=high pH varieties of tomatoes- I only grow heirloom tomatoes with normal pH)I check pH, but I usually don’t feel comfortable unless the pH is below 4, because what if my little dip sticks are old I am not reading the color chart right, or something…..

People did used to die of botulism, and dead is dead.  A woman I knew fermented her food waste for her chickens, (I have no idea why!) it went anaerobic, and a couple of her hens ate it, were paralyzed and died.  I think she would have lost all her hens but that she was watching, the first couple hens showed symptoms quickly, and so the others didn’t get a chance at it.

If you can non acid foods like green beans or potatoes or chicken or fish, use a pressure canner, AND compensate for elevation.  The higher temperatures deactivate the spores.  Longer time in waterbath canner will not deactivate clostridium spores.

Refrigerate after opening is a way of manufacturers shifting the responsibility to the consumer.  Use by dates have increased the sales of some products by up to 25%.  Since when did honey go off? It was found in the pyramids and tasted OK, apparently, after 2000 years.  Manufacturers are finding new ways of making jams and spreads that will drop the input costs.   As pointed out in previous posts, preservatives are being removed from manufactured products because of public pressure.

So to the home made jams, the making of jam is both an art and a science.  There is a relationship between acids, pectin and sugars.  Fruit contains fructose and small levels of sucrose.  Sugarcane sugar is 100% sucrose Sugar will not gel in a low acid environment.  Think Toffee - the sugar turns to toffee with the addition of a tablespoon of vinegar (the acid).  The other bit of science is a gel factor so the jam is not toffee like. This is achieved through pectin.  Some fruit such as apples, citrus and raspberries are very high in pectin.  By combining fruits and sugar, it is possible to achieve the the right balance to achieve "Jam-set."

The art is knowing how to manage the heat and knowing how to tell when the jam is done.  This can be done by a few ways.  We use the frozen saucer method: take a saucer that has been in the freezer for a few hours and place a drop of jam on it.  Wait 20 seconds until the drop is cold and press a fingernail against it.  The Jam is done if a skin appears to wrinkle on the surface of the jam drop. https://preserveandpickle.com/test-jam-setting-point/

We have taken to adding apples at a rate 2 parts fruit to 1 part apples.  EG: 1 Kg Strawberries, 500 G Apples and 1.5 Kg sugar we add 100 ml Lemon juice for acidity.  This gives about 6 X 250 ml jars of jam when finished.
Apple gives both pectin and fibre plus tempers the sweetness.  We always grate the apple and add immediately so it does not go brown (oxidise).  The mixture less the lemon juice is soaked for 12 hours to draw the juice from the fruit.  Stir the mixture and put on the stove to cook.  Add the lemon juice after the sugar is dissolved and the mixture boiling.  Continue to cook at the highest setting, stirring regularly to prevent burning. Once the mixture stays on the pot side, start testing for setting.  Jam needs to be cooked quickly to achieve gelling or it becomes  toffee-like.
Bottle in small jars and place lids on ASAP.  By turning the jars upside down, the lids are sterilised.  Wait 5 minutes and turn the jars right way up and leave to cool.  The jars will seal.  Label once cooled.  Jam is much better once it has had time to mature.
Make sure that only a clean knife or spoon is used to remove the jam from the jar and the lid is replaced as soon as possible.

The mould that forms on the jam is easily removed and does not detract from the taste of the jam.  A mould layer acts as a barrier to bacteria and other yick.  It is removed with a spoon by scraping.  We have kept home made jam for over 5 years sealed and it was still in good condition.  

Hope that this adds another dimension to your jam making.  We make 900 jars per year to sell at a local co-op.

My husband and I have traveled to both the UK and Greece where we observed open jams stored in the cupboard at the homes we visited rather than in the refrigerator. I thought that was very interesting and wondered at the time if it was because we're now afraid of "germs" here in the USA. Another thought that occurs to me now is that we generally keep our homes warmer (at least in winter) in the US than some other parts of the world which could speed up spoilage. There's also the possibility of different commercial processing standards for jams in those places than there are here. I know that in many parts of the world you can buy shelf stable "milk" in bags. It tastes like milk, but I question whether it has much food value left after all the processing that makes it shelf stable. But that's milk not jam.

I usually keep open jams and jellies (homemade or store bought) in the fridge or freezer to be on the safe side. If I don't have room for some reason, I smooth the top of the jam and close the jar tightly and leave out. I've not had spoilage doing this, but we use a lot of preserves in our house so it doesn't have much time to go bad. We do the sniff test and if there's discoloration we remove the top inch or two to be safe. No issues so far.

On the occasions when a fruit preserve molds in our house, it's usually because a crumb got into the jar. When we use clean utensils, we don't usually have that issue.

Done was it by my Grandma and old Auntie using Gelling Sugar which was in the 60's and 70's in every store available.
The only magic of this sugar was it had pectin mixed in.

That was also the reason that some jams made by the rule 50/50 fruit/sugar were still a bit runny and others hard like a Haribo gummy bear.
This was depending on the natural pectin content of the fruit used.

But I remember after opening it could build up mold either in the fridge or outside, but to last longer a squeeze of lemon juice or even E334 tartaric acid for very sweet fruits was added.

IMHO, the guidelines about water canning jams and jellies came about as an extra safety precaution. Especially since people started making jams and jellies out of low acid foods - garlic jelly? - really, can't imagine it. Fruits do have some acid and that combined with sugar creates an environment that is not friendly to the growth of harmful bacteria. The previous post explained how to raise the acidity at the surface of a jam or jelly. Thanks for the great hint. Mold growth on the surface of jams and jellies was common when I was a kid. I remember prying the paraffin layer off and finding mold which was just scraped off. However, I don't think I would feel comfortable eating some kinds of non-fruit, home processed jams and jellies that were not water bath canned.

I had presumed it was because the manufacturers started using corn syrup in place of sugar. I checked a jar of fruit spread which is made with sugar. It bore the same refrigeration warning. It may be that they are not using as much sugar as in the "old days" (likr the 1960s).

[quote=tom olofsson] I had presumed it was because the manufacturers started using corn syrup in place of sugar. I checked a jar of fruit spread which is made with sugar. It bore the same refrigerator warning. (likr the 1960s).[/quote]
That, too, may be a factor. The USDA, though, now states that home canners should always process jams and jellies in a water bath canner. Even if they use only sugar. My Mom, and I, have always poured the hot jams or jellies directly into hot sterilized jars. We both used sugar, and mold was still a problem.
People preserve foods in mostly 7 ways: 1) drying, 2) creating a high Osmotic Potential (OP) by adding mostly sugar or salt, 3) canning to kill in situ organisms and sealing off any reentry (as Louis Pasteur did), 4) acidification, 5) the addition of toxic compounds as in smoking or the addition of preservatives, 6) freezing, and 7) irradiation. Most preservation is a combination of 2 or more of these seven methods.
Simple fruit jams and jellies depend upon a high OP and a little acidity. As a side note, jams and jellies and other high OP substances such as honey will pull water out of the air at the surface of exposure. This lowers the OP at the surface to the level that mold can grow. So, besides using a clean spoon, keep jams, jellies, honey, etc. tightly covered for storage even in the refrigerator. The most common mold, Penicillium, can grow at refrigerator temperatures.
Back to corn syrup. I don't know (haven't researched it), but it could, quite possibly, have an OP that is too low for adequate preservation.
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I should have mentioned fermentation as it is so important in food preservation. Fermentation spans two of the preservation methods listed: 4) acidification, and 5) addition of toxins because there are 2 types of fermentation: anaerobic and aerobic. Anaerobic, or lactic acid, fermentation by certain types of bacteria produces lactic acid as an end product and is used in pickling. Aerobic, or alcohol fermentation by certain types of yeasts produces carbon dioxide and ethyl alcohol (a toxic compound) as end products and is used in making beer, wine, etc. An interesting point about fermentation is that neither the lactic acid nor the ethanol are directly added to the food being preserved, but, rather, we depend upon the metabolic activity of living organisms (that are present naturally or are added to the food) to do this for us.

My wife made a batch of apple butter last Fall and then hot water bath canned it. To me, it seems like a thickened apple sauce rather than the thick apple butter I knew as a kid. Steve Edholm at Skillcult has a great Youtube.com video on pre-1900 apple butter. Apparently, apple butter back then was often made in large quantities and stored on a shelf and slowly consumed over a period of up to several years without a problem. The video is well done and well worth watching - especially for those who like apple butter, and it includes how to make old-time apple butter.