I'll paste in the conversation that happened in the Food Preservation group as a starter - thank you, Doctor, for your wisdom and guidance!!Harriet:
It is good to understand the alchemy of jam making. Most importantly, that fruit has water in it and that cooking it down with the sugar is what makes the syrup that makes the "jam". In essence jam is fruit suspended in cooked down syrup. Oh gosh. You see I teach food preservation and am damn near obsessive about the topic and it is hard to explain easily. Many folks like low or no sugar jam and I get the desire so using Pomona is the best way to go. Its not my approach but I'll go with the assumption that you like it and want to use it. I'm not sure of the recipe but perhaps if you soak your fruit with the sugar (what sugar you do use) overnight, it will allow for some of the juice from the fruit to mix with the sugar. The sugar will also permeate the fruit (most importantly if you are leaving it in slices) and help to saturate the cell walls so they hold their shape better. The sugar will sort of "dry out" the fruit or such out the water. Not a lot but it does work that way. But again, I'm not looking at the recipe. I would try those things and see how it works. I know Pomona is the most flexible of the box pectins. Does that make sense. I could go into this more and at another time I will tell you about my food preservation dvd which I never know if I can mention or should but I believe in it.
Pat - my ratio is half as much sugar as fruit. Always. I marinate the fruit and sugar overnight. Then I make the jam in a wide wide saucepan (paella pan or the like) so the liquid surrounding the fruit after the marinating stage (and it will look very liquidy) will evaporate quickly given the wide open surface area, anywhere from 10 - 18 minutes to set. I pour the stuff in jars and let it sit overnight to let the natural jelling of the natural pectin in the fruit to do its work. Jam will continue to set for 24 hours.
The reason I use a wide shallow pan (very important) is that using a tall sided pot will keep moisture in and you want to boil it off quickly so the fruit keeps more of its vibrant taste. You also want to reduce the liquid to a certain sugar to liquid ratio. Think science here. No matter how much sugar you add, its ability to mix with the rendered liquid from the fruit to form a syrup (first) and then a thick gel consistency is all about the ratio. That ratio and the ensuing gel texture you are working towards is what sugar is all about in the land of jam.
But jam making also requires pectin and acid which most fruit has enough of. That is a very important point to understand. We generally don't need to add pectin or acid except in a few situations. That we do all the time has more to do with an industrial system of jam making that has been handed down to home cooking than anything else. It may apply to them but not to us. Here is the reason:
High temperatures will kill natural pectin. The problem with industrial jam making, is that cooking huge quantities in huge tall sided pots requires really long high temp. cooking times that destroy the natural pectin in most fruit. So that is the main reason they use it and why industry came up with boxed pectin in the first place--- they needed it. They need it to either make up for the pectin that was lost during long and high temperature cooking or to pump up the volume by adding lots of sugar. Remember the ratio thing. Well if you don't want to cook it down at all and you want a gel texture you got to add something to make it happen - pectin. And in the case of freezer jam, lots and lots and lots of sugar and corn syrup. Egads.
Since sugar is cheaper than fruit and can become a filler and improve profits, industry loves it. So whether it is because of the use of sugar as filler or the long cooking times, for industry, pectin is a must. What most home cooks are doing when they use boxed pectin is replicating a process that is relevant for huge batch, huge pot industrial cooking. But that's not us.
Now you might need it if you want to increase the volume by adding lot of sugar or because you don't want to cook it at all or you want to make a huge batch at once and need to use a tall pot but I generally start with 4-6 cups fruit and half as much sugar and that makes a reasonable amount (4-6 half pints). I do that with a couple of different varieties so I have some selection. But a caveat to all this is that some fruit is a little low in natural pectin and then, and only then, do you need to add it.
Most time the cooking process is enough. Strawberries are one of those fruits that are low in pectin and that's when I add my home-made pectin stock but I could throw in a few currants or grated apples during the marinade period and that would would normally do the trick. In essence I'm adding natural pectin to a low pectin fruit. No box necessary.
One must understand the function and natural quality of pectin and its role in making jam if one is to side step using the box. And really only a few fruits need any additional pectin. If I needed to avoid sugar all together I would use Pomona since its the best of the bunch, but short of that I would follow my recipe and forget about the box.
Another note: Mashed fruit jams will set faster because of the added fiber in the syrup. Sliced and whole fruit takes longer since the syrup does not have any added bulk from the fibers.
So, to answer your question (finally) Pomona goes a long way to help those who cannot or do not want to eat sugar to make something reasonable but I still don't like the texture or taste. For me, if and when I eat jam, I am treating it as a condiment and using it sparingly.
Genna asked: “Harriet, will peaches require pectin or do they have enough on their own?”
Harriet: Peaches are one of those low pectin fruits so a little added to the mix might be good. Certainly you should add some lemon juice (which is high in pectin as well). I would slice your peaches, weigh them, add half as much sugar in weight as the peaches, mash or leave sliced, let sit overnight, stir every so often to distribute sugar crystals and if it is not to hot in the house you can leave it out overnight (this is also the time you can add other flavors like ginger or lime rind or whatever if you want it). Next morning throw it in the wide pan (with at least an inch of space above the top of your fruit so it allows for the boiling bubbles) with lemon juice. I would use 2 T. for each pound of fruit. Now bring to a boil, skim the foam once it comes to the boil but do not stir it for the first seven or so minutes. Just let it boil. This is when the fruit syrup is really reducing. Remember, you want to let the syrup become thick and rapid reduction is part of the trick. I start stirring from time to time after that and let it go another three to seven minutes or more. Which peach, if you mashed it, I would figure the entire process should not take more than twelve minutes or so but this you will only get good at as you do it and make your mistakes. Sorry but that's the way you get good at anything. Just remember though, do not cook it to the consistency that cooled jam looks like otherwise you will have a really solid mass when your hot jam cools. It should be a bit loose when you are ladling it into the jars. It will continue to set up over the next 24 hours. If you go to my website www.portlandpreserve.com you will find a place where you can order my dvd so you can see the process in action but I suggest you give it a go on your own first. Just keep the faith and you will have something really great. And if, for some reason, it does not set up entirely to your liking the first time, just consider it ice cream topping and know to cook it a bit longer next time. That is how you learn. Go forth and report back.
Also, what applies to peaches applies to strawberries - both naturally low in pectin and acid.
Later…Pat used Harriet’s ratio, and thought it too sweet, and asked: “Was I supposed to add the lemon juice at the end of the cooking or the beginning?” In response, Harriet writes:
Harriet: Yes, half as much sugar but you can try next time using less. This is about cooking which requires flexibility as much as recipes. Jam making is no different than anything else in the cooking world except that the universe has freaked us out about making it. So that is what I meant. If it tastes too sweet you can reduce the sugar a bit more and see what happens. You were to put lemon juice in during the cooking but you can also through in other high pectin fruit or my pectin stock when and if you ever get the dvd on how to make it. But then the info is also on my site which you already know about I think.
Here is a short story on pectin - it exists naturally in all fruit. If you cook small batches of jam you do not need to use any no matter what sort of fruit you start with. Honestly. Here is a basic recipe that can stand in for almost all fruit you use.
3 cups mashed or sliced fruit
1 1/2 cups sugar
Marinate overnight - in fridge if hot in the house otherwise in the fridge. Stir occasionally to dissolve sugar crystals.
Add 2 T. lemon juice (fresh squeezed please)
Next morning (or whenever you get to it - it will keep) bring mixture to the boil in a wide shallow sided pan (not pot). You want the mixture to evaporate quickly.
Cook 10 -15 minutes depending on moisture of the fruit. Stir as needed so it does not stick.
Put in jars. Attach lids and rings. Water bath if you want. With small batch you will probably go through it quickly enough that it will not require processing. Jam is high acid. Between the sugar and the fruit, nothing scary will grow in there. Besides, the heat of the jam (or the cooling off of the jam) will cause a natural sealing process. Let rest 24 hours since the natural pectin in fruit will continue to gel over time. That's it.