Marmalade

[shadwellstair]

It's marmalade making time again here and I've been googling new recipes.  Most of the American ones I've found boil the jars again after they have been filled - I've never heard of this before.  I'm in the UK, and I've always just boiled it to setting and poured into hot jars.  So what is the purpose of the extra boiling?
Thanks!

[trailgrrl]

The purpose is to properly sterilize the jars.   It's the way my Grandpa taught me.     I'm in the US.

[buvezdevin]

The process of boiling filled jars, which were sterilized before filling, is to ensure proper sealing.  Boiling the filled jars (for a period of time determined by volume and type of food) forces air out of the jars and kills bacteria which may be present in the food.

[MummySweet]

The second boil also ensures a good seal on the jars.   The thought is that the jars/lids cool some during the filling and may not seal as well.   In addition, the second boil is intended to kill any germs introduced during the fill process.

We lived in the UK for nine years.   I was always surprised how common it seemed for people to reuse product jars and lids for their canning, often using a paraffin layer directly on top of the canned jams, etc.   In the States it seems more common to use two-part canning lids and heavier glass canning jars.     But I ate plenty of home-canned things in the UK and never got sick and developed a love for quince jam!

[ITSJUSTME]

I respectfully disagree with trailgrrl and agree with buvesdevin however, the jars are only sterilized before filling if they are boiled in water or washed in the dishwasher on a hot setting and left in there until wanted.

Also the lids and rings should be simmered in a pan of water to both sterilize and to soften the sealing materila on the lids.  The jars are then boiled in a water bath after filling to properly seal.  As the heated contents expand air is driven out and a vacuum is formed when they cool.

If you do not boil the filled jars it is usually recommended that the contents be refrigerated once cool.  Some people believe refrigeration is detrimental to the flavor.

The method of filling and hoping for a seal is usually (in my experience) recommended only for jellies though I could not tell you why it's okay for them and not for other preserves.  Best luck - I adore marmalade.

[magicdomino]

The second boil also ensures a good seal on the jars.   The thought is that the jars/lids cool some during the filling and may not seal as well.   In addition, the second boil is intended to kill any germs introduced during the fill process.

We lived in the UK for nine years.   I was always surprised how common it seemed for people to reuse product jars and lids for their canning, often using a paraffin layer directly on top of the canned jams, etc.    In the States it seems more common to use two-part canning lids and heavier glass canning jars.     But I ate plenty of home-canned things in the UK and never got sick and developed a love for quince jam!

My (American) mother did that.  Jam and jelly were never processed, just sealed with paraffin.  Every once in a while, a jar would mold, but most seemed to keep well for a couple of years. (That or we developed immunity.  )  Part of the reason this works might be cooler household temperatures; all of our home-canned goods were stored in an unheated room in the basement, and I understand that UK households were traditionally cooler during the winter than American ones.  The other reason is that high concentrations of sugar have an antibiotic effect.   The paraffin method will not work with any kind of low-sugar or sugar-free jelly.

[shadwellstair]

Thanks to all of you.  That does make sense.  I think you have it correct about the sugar, MummySweet.  I have been making marmalade for 30-odd years now and never had a mould problem.  However I have had the occasional problem with jam (one reason I concentrate on marmalade!), which has a lot less sugar to fruit.

[shadwellstair]

Sorry, magicdomino, not MummySweet.