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Jelly, jam and candy
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Dilbert



Joined: 19 Oct 2007
Posts: 1007
Location: central PA

PostPosted: Fri Jun 27, 2014 7:40 pm    Post subject: Reply with quote

all true - but it still leaves the issue of "I followed the directions exactly and it turned out runny!"

a lot of recipes / directions just don't bother with a temperature thing - they rely on just 'continue to cook for x minutes'

but, if the magic temp - which is in the range of 221-225'F - can be slightly higher for (thick) jams/marmalade with low pectin fruits - is not reached 'accidentally on purpose' - it does not set up.

those temps don't really require a candy thermometer. the candy thermometer thing came into the discussion elsewise.....

as pointed out, there's a lot of variables. to make the magic work, the pectin, sugar and acid needs to be 'in proportion' - altho there is quite some latitude in the proportions. added (powered) pectin requires more sugar - people are trying to use less...

sticking a thermometer in the pot is not exactly burdensome - but it can give more reliable results that guessimating.

Jack's wife's notes: just add pectin and bring it to a boil can in fact work peachy keen.
if there was not excess water in the fruit
if it's left at a boil long enough to kick-over
if and if and if.

I prefer a thermometer (g)
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Jim Cooley



Joined: 09 Oct 2008
Posts: 316
Location: Seattle

PostPosted: Sat Jun 28, 2014 1:43 pm    Post subject: Reply with quote

Quote:
Extremely ripe fruit can also be a challenge as the ripening process breaks down pectin naturally,


Okay, that's a very plausible explanation for why my jams don't set very well. I use really ripe blackberries, and just the recommended amount of either liquid or dried pectin. (which leads me to ask, does that stuff have an expiration date?) I also use smallest amount of sugar in the recipe, because the riper the blackberry, the more sugar it contains.



Quote:
Some acid typically helps though.

Can you elaborate on this? How important is the acidity to set a jam or preserve? I do have citric acid powder sitting around and the increased tartness would not be objectionable. (too sweet IS objectionable, though)

Appreciate the thoughtful reply.

Jim
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Jim Cooley



Joined: 09 Oct 2008
Posts: 316
Location: Seattle

PostPosted: Sat Jun 28, 2014 1:50 pm    Post subject: Reply with quote

Quote:
but, if the magic temp - which is in the range of 221-225'F - can be slightly higher for (thick) jams/marmalade with low pectin fruits - is not reached 'accidentally on purpose' - it does not set up.


Duly noted. Thanks Dilbert!

Still curious about the chemistry of pectin. Any difference between the powdered and liquid varieties? Does it have an expiration date? Should I keep the stuff in the freezer because constant exposure to room temp will make it "break down"?

Jim
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Dilbert



Joined: 19 Oct 2007
Posts: 1007
Location: central PA

PostPosted: Sat Jun 28, 2014 2:40 pm    Post subject: Reply with quote

the basics of pectin:
http://www.rsc.org/chemistryworld/podcast/CIIEcompounds/transcripts/pectin.asp

typically I buy the smallest amount possible - if it's not in the store section with the other canning stuff, the health food store has it.

I don't keep it after the 'season' - at the cost of fresh fruits around here, a batch of jam/preserves - four to six jars worth - runs pretty close to $20 and I'm not going to risk the time and effort using stale stuff.
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Jim Cooley



Joined: 09 Oct 2008
Posts: 316
Location: Seattle

PostPosted: Sat Jun 28, 2014 4:26 pm    Post subject: Reply with quote

Dilbert,

More than I ever wanted to know about pectin. Thanks.


Mera naam Jeem
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