Of course, the very point of jams and chutneys is to preserve the ingredients so it hardly surprising they have such long shelf-lives. They are after all, full of sugar and vinegar in the case of chutney, both of which are natural preservatives. They are also cooked at a high temperature and bottled whilst still hot into sterilised jars. The lids too can be steriled in the oven or sterilised by turning the jam/chutney upsidedown to rest on the lid whilst still boiling hot.
Some people comment to me that they sometimes find that their jam goes mouldy after opening. This shouldn't really happen but it does sometimes. There are always mould spores in the air and these can get into the jars whilst the lids are off or from the knives and spoons poked into it. One of the worst things to do is to push your knife into the jam after you have spread butter or margarine on your bread as the breadcrumbs and butter are a lovely starting point for mould. Generally however, jam should be fine to store at room temperature after opening but eat it up within a few weeks of opening. Jammy Cow jams are perfect for this because they come in small jars.
At this time of year I like to make Elderflower Cordial but in the past I have been limited to the number of bottles I could fit in my fridge as they tend to go mouldy in the bottle at room temperature. The problem with Elderflower cordial is that it is left out (covered of course) for a day or so for the flavours to infuse and it is bottled cold. Not deterred, I did a bit of research and found out how to pasteurise it so that it could be stored at room temperature until the bottle is opened. This turned out not to be too tricky so now I can make lots more bottles and offer them to the public for sale.
The cordial is poured into sterilised bottles to within about a centimetre of the top. The bottles without lids on are stood in the preserving pan and packed out with empty jam jars so that they are held tight and are not at risk of falling over. It then takes 3 kettle fulls of boiling water to fill the preserving pan. This is then heated on a fairly gentle heat until the cordial temperature reaches 70°C. The heat is reduced and the temperature is maintained for 20 minutes, in which time the cordial expands in the bottle to fill it completely. After that the tamper-proof lids are applied and secured and then the bottle inverted to sterilise the lids. The cordial remains sterile then until opened, after which it needs to be refrigerated and used up within about a month.
I'm pleased to have cracked this technique and increased the shelf-life of this lovely product and I think I shall be experimenting more during the summer to pasteurise our other family favourites such as Blackcurrant & Lemongrass cordial and raspberry and strawberry syrups which are great for flavouring milkshakes, yoghurts and pouring on ice-cream sundaes.