wire-top kilner jars

[dave45]

not done any fruit-bottling for donkeys years
blackcurrant glut
freezer full
was gifted a load of new kilner jars with wired-on lids and rubber seals.
I have totally failed to get a seal with these.

my method:
1. sterilise jars in oven, minus rubber seals
2. burn fingers installing rubber seal and getting it nice and even
3. pack with picked-over berries to about 2cm below the top
4. top up with hot syrup to about 1 cm below the top
5. fill jam pan with warm/hot water and drop some paper/cloth in the bottom to buffer the glass against too much heat
6. clip on jar lid and immerse in water
7. gas to max
8. watch bubbles escape from 1 or two points around the seal
9. fish out hot jar and place on newspaper. open lid. gas down
10. inspect seal, clean around rim and seal (and burn fingers again)
11 go to 6

after 4 times around the loop I continued the process and let it cool overnight.
following morning - no seal.
I don't think there is enough pressure to make the seal, yet there is no adjustment possible.

Or I am doing smth wrong... but what?

Don't think I had this problem with the lids and screw-band edition of the KJ

Repeated again this evening with Leifheit KJ with the clear white non-rubber seal.. exactly the same

[Odsox]

I think you are going wrong at number 9
The way it works is that you boil the liquid inside the jar (No 8) to expel all the air and leave the head space full of steam.
Then you remove heat, the jars cool, the steam then condenses back to water leaving a vacuum, which pulls the lid down onto the rubber seal.
When you "open lid" at stage 9 you are letting all the air back in.

[Green Aura]

Yes, I think that's the problem too.

I rarely use a water bath method. I generally use the oven (minus the rubber ring). I can't remember the temperature, about 110C I think, for about an hour. Then do the same dance as you with the rubber rings and leave them on the wooden chopping block to cool. I've never had one fail to seal or be inedible months later.

[MKG]

Isn't it the contents, rather than the jar, that you're supposed to eat, GA?

Mike

[Green Aura]

It depends how well the polytunnel's producing. Which reminds me - new pics in order, methinks.

[dave45]

Last night I did a 2lb KJ (lid and band), a Leifheit clear plastic wire top KJ of blackcurrants and a re-used Bonne Maman jampot for blackcurrant coulis.

All sealed ok.

The Leifheit leaked bubbles, the other two didn't.

This is the bit that confuses me.

Given that the jars are sealed as they are warming up, why don't they explode from increased pressure as the liquid turns to water-vapour/steam?

I can see that the wire-top KJs mechanism might act as a pressure valve (due to the spring in the wire) and the bubbles are meant to escape. Yet the rubber ones failed to seal and the clear plastic version worked.

Yet NONE of the instructions I have read mention either of these points.

[ina]

I haven't used Kilner jars for a long time - but as I remember, they don't actually get totally immersed in water; water goes up to the level of the contents of the jar. That's the way I do it with re-used jam jars, too, and I've never had anything go off. (I was wondering why you should see bubbles emerge! We never heated them up in the oven first, either; just washed in very hot water and drip-dried.)

[Gra]

I think there is a lot confusion about using kilner jars because of all the nonsense written about them especially emanating from the US. We went through all sorts of convoluted processes, sterilising bottles and cooking fruit beforehand, etc having read such stuff.
The bottles need to be clean, not sterile, before use - they get sterilised in the process along with the fruit. So clean jars, fill with fruit (just cleaned and cut up) and top up with cold water to about an inch from the top, put on seals and close caps and clips (screw tops, ease off by half a turn (I think just half a turn, it's a long time since I used them)). Put jars in water bath of cold water, standing on several thicknesses of cloth to dissipate the heat and covering the jars in water, making sure that the jars can't rock about by wedging them with cloths or flat stones. Bring the water to the boil slowly - this is important, don't rush it - when it starts to boil let it simmer for 30 minutes (some people give lesser times), leave to cool. Take out jars, release clips, check vacuum in jars by carefully lifting jar by holding the lid, redo clip.
This is simple and we have found foolproof (for fruit, vegetables take 4 hours - but who wants to eat vegetables cooked for so long?). The biggest problem seems to be finding a pan big enough to take a number of jars to make it efficient and to be tall enough for the water to cover them. We solved this by buying an old cauldron in France, which has the advantage of using wood as fuel rather than using gas.

[ojay54]

That's my way of doing.In Italy when they bottle passata they use the same method,commonly using an oil drum.

[Odsox]

I don't mess about like that with passata, as it's high acid I just pour boiling purée into hot jars and seal (like jam).
We've done it that way since Adam was a lad and haven't had a wrong un yet.

Don't think it would work with low acid toms though.

[ojay54]

Really? What's the longest you've kept it Tony?

[Odsox]

In the normal course of events well over two years, but it would last a lot longer except it starts to lose it's colour after a while.
The must be high acid types, which is what I grow exclusively.
Even jars that fail to seal stay OK in the fridge for three months or so.

[ojay54]

Tony,I never realised that some Toms had higher acid content than others.Anyhow,not using the waterbath for preserving will transform late August evenings in this house,thanks for that.
You'll know this(but it might be of use to someone) : Square sponge tray (like Swiss rolls type),spread with passata,in a low oven ,as it evaporates the edges become really nice puree,so collect it,a bit at a time and jar it under oil.