I want to start making chutneys/jams at home, but am unsure of exactly how to proceed. Friends I've spoken to have said to sterilize the jars, then just put the hot jam/chutney in, and some online recipes seem to say this too - http://www.bbcgoodfood.com/recipes/7565/marrow-and-ginger-jam . There are also a good number of recipes which need an extra step- boiling the sealed jars (eg: http://www.freshpreserving.com/guides/IntroToCanning.pdf ).

Is one method better than the other? Does it depend on the recipe? Ideally I want the least amount of hastle (ie: boiling the jars after filling)

  • 2
    What's more hassle - boiling the jars after filling or having to throw out an entire batch of spoiled jam? Jun 19, 2014 at 12:14
  • A few people I've spoken to sounded surprised and worried the jars would explode if I seal and boil them. Ending up with boiling jam all over me is unappealing.
    – Echilon
    Jun 19, 2014 at 13:09
  • You don't do the lids up tight when you boil them, just to the 'biting point'. This prevents any pressure build up. Then you tighten them fully. I should also mention that the amount of sugar in your recipe and the length of time you think the jam will be stored for will determine how necessary a second boil will be. Jun 19, 2014 at 13:13

3 Answers 3


Recipes for preserving tend to be very specific. They're calibrated to balance factors like pH and sugar content in the final recipes, and of course to minimize the risk of spoilage. In general, you should always follow the steps as written in your recipe.

What I've generally observed is that jam-type recipes don't always include the final boiling step because the jam is already cooked (edit: and because per rumtscho, the sugar content is generally high enough to be inhospitable to bacteria). That differs from canning fresh fruits and vegetables which are largely raw. The purpose of the boiling step here is to kill off pathogens before they get a chance to settle in and spoil the contents, as no matter how well you clean them, there are likely to be some spores, bacteria, etc. remaining. Even a tiny initial population can grow and spoil your preserves over the length of time they'll be put away.

So, initial sterilization is always required to clean the jars themselves. The second boil pasteurizes the contents. If you've already done this as part of your preparation, as with a jam, then it most likely isn't required. It probably won't hurt, especially if you plan to put up your jams for an extended period of time (i.e. months or years) but you'll have to weigh the convenience of skipping that step against the potential risk of spoilage.

That said, let me state again for the record that if your specific recipe says to include the final boil, then there's likely a very good reason, and you should follow that instruction.


Yes you should boil them if you want them to be shelf stable, otherwise you run the risk of botulism spores taking hold in the jars (or other food poisoning). This is called water bath canning.

I recently made some pie filling this way (which is basically jam) and there were no explosions.

In fact, you can even can juice this way. It will not explode.

Edit: It is important to use a recipe specifically developed for water bath canning, as these recipes have been tested for proper pH or sugar levels such that it inhibits the growth of "baddies" in your jars.


You need to avoid infections so you should clean the jars in very hot water and then dry them out. You could use a warm oven for this if you're using glass. However, it only has to be warm, not at a cooking temperature. If you can't do this, you can let them dry normally but you should ensure they are as dry as you can.

Everything will be quite hot so be careful, definitely a good reason for getting a Jam funnel as that will make life a heck of a lot easier when it comes to putting hot jam into hot jars.

Don't make the jars too hot as you don't want them to cool rapidly and then shatter.

If you are using flip top jars rather than screw top jars, you must take the rubber seal off (thinking Kilner style jars here) as you can just pour boiling water on those and dry them.

You should also consider getting wax discs to put over the jam/chutney if you are leaving it for a while. This is probably more for jam than chutney due to the different ingredients used.

I recommend going to your local home store and looking at the home cooking aisles for the funnel and discs. I recommend also getting labels rather than using a permanent marker if you can as its easier to re-purpose the jars later.

  • I know I need to sterilize the jars first, but do I need to boil them afterwards too?
    – Echilon
    Jun 19, 2014 at 13:11
  • I never have. I've never seen it required in any of my recipe books either.
    – Simon
    Jun 19, 2014 at 13:31

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