What causes a batch of Certo thickened jam to not set?

Question

I made a batch of fig jam and the batch did not set. My only deviation from the recipe(Kraft's Certo Fig Jam) was accidentally cooking the jars in the water bath longer than indicated for sealing. Does overcooking the batch cause Certo to stop working correctly? If not, what could have happened? Is this just one of those "off" batches that didn't thicken?

Answer 1

No, canning for a longer time than specified for sealing didn't cause the failure to set.  Figs are notoriously difficult to get to set because their natural acid content and natural pectin content are low.  You can remake the jam according to the instructions with the Certo.  But this time ignore the cooking time and have a glass of water near the cooking pot.  After the mixture comes to a boil that can't be stirred down, use your stirring spoon to let a drop of the mixture fall into the water.  When the drop forms a soft ball and falls to the bottom of the glass remove from heat, ladle mixture into clean jars, affix a new lid and re-process.

I recommend you use the Pomona Brand Universal Pectin the next time you make fig jam/preserves.  This pectin uses a calcium compound (monocalcium phosphate) and acid (lemon or lime juice) to set the jam rather than acid and sugar like regular pectin such as Certo, Ball, etc.  You can use sugar, honey or Splenda to sweeten the jam to your desired taste.  Pomona brand pectin can be found in many of the supermarkets and "mart" type stores and hardware stores that carry home canning supplies and also in most health food stores.  This type of pectin has been used commercially for more than half a century but has only become availble to consumers in the last few years.  Here's the link to their Pomona's Home Page;

http://www.pomonapectin.com/recipes.html

Answer 2

well i make blackberry jelly, and sometimes u just have an off batch, although over cooking it could cause some problems.