Jam Making - Sterilising Jars - Ideas Please

I'm back into marmalade making mode & looking for a better method of sterilising my jars than putting them in the oven.

I've been on Google & got some ideas but would like to hear some suggestions from Kiwis, particularly for doing them in the microwave.

Best I came across was:

• six jars
• 1/8th full of water
• high 3-4 minutes

I tried this & they didn't seem to be very hot - maybe my idea of 1/8th was overdone.

If I do continue to do them in the microwave, what is the best method to do the lids - the typical metal ones with the rubber ring stuck to the inside. Same for preserving jar steel lids.

Interested to hear your methods. Thanks.

Be careful with the old Agee jars - if they are heated too high, they will crack. Otherwise, I don't know about microwaving them, I just put them on the stove on a boil for 10 minutes.

Toast;379078 wrote: I'm back into marmalade making mode & looking for a better method of sterilising my jars than putting them in the oven.

I've been on Google & got some ideas but would like to hear some suggestions from Kiwis, particularly for doing them in the microwave.

Best I came across was:

• six jars
• 1/8th full of water
• high 3-4 minutes

I tried this & they didn't seem to be very hot - maybe my idea of 1/8th was overdone.

If I do continue to do them in the microwave, what is the best method to do the lids - the typical metal ones with the rubber ring stuck to the inside. Same for preserving jar steel lids.

Interested to hear your methods. Thanks.

Sorry Toast, I don't know about microwaving either. We just wash them thoroughly, and put them wet into the oven to dry and get hot, then the filling is hot, the jar is hot and the lids are hot. All put together - presto! Lids pop down when cooling. We've still got jar from years ago that are still fine. So this method works for us! We re-use commercial pickle jars and jam jars etc. Haven't used AGEE jars for marmalade etc just the standard ones.

I put mine into the dishwasher - they come out hot and dry...

dishwasher here as well

I haven't done it in years but always did what Robinson's Folly explained. Never had any failures. Bearing in mind that this was Agee Jar days so maybe things have changed with what you are using to preserve in?

Yes, I was going to suggest the dishwasher as I've heard they do the job...I tend to use the oven but have had a few disastrous cracking incidences [:0] which annoy me because they not only make a huge mess but also waste my precious preserves! [}]

Then I suggest that your oven is running hotter than you think it is. When marmalade is ready to set and put in the jar, it's boiling temperature is about 120C. Thus you want your oven running at about that temperature. Not much hotter nor colder. I suspect that both the dishwasher and the microwave oven method will not get the jars quite hot enough, so you are more likely to have breakages with these methods. Neither the microwave nor the dishwasher can get the jar temperature much higher than 100C.
Sterilisation of the jar is not very important, because nothing can grow in marmalade that sets properly. The problem arises if bugs drop out of the air onto the surface of the jam as it is cooling, and condensation forms on the jars top. If this condensation falls onto the jam then the bugs can grow and spoil the jam. So if you cover the jam immediately the jar is full, with a re-used top or an Agee seal, you are likely to have no problems.

I normally do the oven method, 30 mins or so at 100c. I have done microwave too. Hubby cooks feijoas in the jars in microwave at same time (bottling not jam making). I tend to boil lids in pan on stove for a couple of mins but in saying all that my inlaws who have been making preserves for years don't sterilise but wash thoroughly in hot soapy water and rinse/dry and then put boiling jam/marmalade into them and don't have any mould forming as per Rothwell's explanation.

For a small number of jars I just put them in a big pot on the stove and boil them (jars and lids) then lift them out with tongs. It's handy to have a pot full of really hot water for cleaning up all the sticky messes you make while jam-making.

A friend recently sterilised his jars in the oven and obviously made them too hot because they imploded when he put the marmalade in them. Very disappointing!

I always do mine in the microwave. A bit less than half full of cold water and bring to rolling boil. Make sure all jars are at that point as some glass is thicker than others so it takes longer. I do 4 or 5 at a time. Put the rings and inners (for preserves) or lids into a pot of boiling water on the stove, keep at a simmer and use as required. Its easy, and doesn't take much time. Better still you can make the marmalade in the microwave too so easier to wash up. I don't have a recipe for that though.

Thanks. Good info - interested to hear different methods. Been making marmalde in the microwave & now that I've worked out to do it without a lid, it's working perfectly.

Warehouse & some other stores have the huge (3.8 litre?) Pyrex bowl which is perfect.

Thanks again.