[Fishyhaddock]

In July I made lots of strawberry jam - some okay, some with the fruit floating to the top. I store them in the garage and yesterday I noticed mould at the very top of the seal on most of the jars.
 
Is it a case of I didn't screw the tops on tight enough or I should have filled the jam to the very top of the jar (left about 1 cm) or that the seals / wax paper were rubbish. Or, dare I say it, all 3? At the time I thought that I had sealed all of the jars okay but clearly not. Any thoughts and can the jam be rescued?

[doganjo]

I've had that happen too, as well as runny jam, and jam that would stand on it own out of the jar.  Just scrape the mould off the top, and if you want to give any away check it doesn't have mould first by looking up through light.  I think it could be cause by any or all three reasons.  Also did you sterilise the lids as well as the jars?

[Cinderhills]

Like doganjo said, make sure you sterilise thoroughly the lids and tops of the jars.  My Aga is so great for doing this and touch wood, I haven't had any mould.  I've had some jars since Christmas and they are all fine so far.

[Rosemary]

Putting the jars and lids through a hot wash on the dishwasher will sterilise them. You shoudl fill to the top but Annie's right, scrape it off - it will be fine.

We entered jam in hte local flower show a few years ago. As usual we were in a rush and Dan raced round the house and garden the morning of the show, collecting stuff to enter. The judge said the jam woudl have won except for the mould on the top - Dan didn't think to check it before hand. We ate it though and it was fine.

Strawberry jam is hard to set - I have six jars of strawberry "sauce" in the cupboard. It's lovely in yogurt, on icecream and especially on cheesecake.

[Samantha]

Hey there .. mould usually indicates that sterilizing was the problem ... put any metal lids in boiling water.. if you just have a glass jar then put a bit of water in it... lay it on it's side and microwave it for 2 mins (they will be REALLY hot when you take them out so use gloves) ... empty out any remaining water fill with jam then take the lid out using tongs and put on the top sealing tightly.

This has always worked for me without any probs and is a quick way of sterilising

Sam

[Hermit]

Strawberry jam is one of the harder jams to make , thats why it features in shows a lot. To make the strawberries go through the whole jar and not settle you must allow the jam to cool before potting. I place my jars and lids in a hottish rayburn for a minute or two to sterilise, and allow to cool a bit before potting so they dont crack.

[Rosemary]

Delia says to use slighty underripe strawberries. I tend to use ones that are too ripe, since my jam making is usually a panic measure when we're knee deep in fruit 

[Fishyhaddock]

Thanks everyone. I reckon that the lids are the problem and some of the plastic seals look a bit suspect. SOOO my neighbour reckons that if I scrape off the mould and boil it all up again, stick it in jars right up to the top and then fit the lids (no plastic seal just wax paper) that should do the trick. Actually tasted some, minus the mould, and was v nice. So all I have to do is wait for a rainy day and get cracking, which shouldn't be a problem up here in aberdeenshire. It's very labour intensive isn't it?

This is my first attempt at jam making - hopefully next year ill have lots of blackberries which will be a bit easier!               

[Fleecewife]

Lakeland do jam pot lids - the screw-on, plastic lined kind and it is worth buying new ones, especially for chutney which corrodes unlined lids and evaporates through the clear jampot covers (they do mail order).  I do re-use jam lids a couple of times, but check them carefully for dents which would let the air in, as well as sterilising as others have said. It is also worth putting the lids on while the jam is still very hot so you get a good vacuum seal.  I fill my jars to above the 'shoulder' of the jar but leave a small airspace.  I also put on wax discs (shiny side down) to help with sealing.  I have been making jam since I was a kid and I don't think any has ever gone mouldy using this method although sometimes in the early days I had batches which wouldn't set (went syrupy) or which crystallised in the jar after a year or so.  I have mostly got my recipes sorted out now, but I'm still hopeless with marmalade.  Keep trying - homemade jam is the best 

[ser3dan]

Morning!
I was just going to suggest taking off the top 3/4" ( along with the mould ) and then boiling it all up again. Did you put lemon juice in for the pectin to help it set?
I fill my jars to the shoulders just the same as Fleecewife does, and wax paper shiny side down. If you have some odd sized jars you're using ( I have a few every year ) then Lakeland also do bigger waxed paper discs for cooking burgers - just cut them down to size and problem solved!
I've found that letting it cool slightly before putting into jars stops the fruit from floating up too.

Dan.

[Fishyhaddock]

Spent 3 hours yday boiling it all up again, sterilising via dishwasher and topping rght up to the top. Hopefully it's now a mould free zone! Dare not cost it out based on man hours...

[OhLaLa]

Hmmm, if I'm given jam with mould on it (9.5 times out of 10 it has) I chuck it straight in the bin (in secret - tricky - hate to offend by refusing). Years ago I was told the mould spores go deep down into the jam, deeper than you can see, so that did it for me....

 

When I make jam I make sure I steralise jars in the oven. I never use the lids (but I do for chutneys and then they are also steralised in the oven). I use the wax paper and then the clear plastic that comes in the 'sealing kit' with an elastic band around. I store in the fridge.

This has worked for me and I have never had mouldy jam or marmalade.

 

[Anke]

I have made my own jam for about 10 years now, even did it wen we lived in the big city... never any problems... however this year almost all my strawberry jam, some of the tayberry and some of the redcurrant jelly has come up with mould on the top. Not sure what happened, I use jam sugar (with added pectin an dhave done so for years too).
As this is the first year this has happened, I am thinking that something with the sugar was not working... am so upset - can't give any jam away now.... thankful for a good honey harvest!

Would be intersted to know if others had a similar problem...

the strawberries and tayberries came from the local fruit farm... and we had quite a lot of rain during July...