You will want to use a high DE pectin.  The pectin will set by solids, temperature, and pH.  Typical solids is 78-80%, this will dehydrate the pectin enough for it to set.  The temperature needs to be kept hot until deposited or sheeted, otherwise you will get pre-gelling.  The acid, lowering the pH will set the pectin, pH should be 3.1-3.5.  As soon as the acid is added, deposit or sheet as it will start to pre-gel quickly.  Lower solids and higher pH will give a slower set, high solids and low pH will give a fast set.  There is also a lot you can do with the pectin type, not only deciding on apple or citrus, but the DE (also called DM) as well.

Citrus pectin is typically a cleaner, clearer gel.

You also want to look at how much protopectin you're adding with the fruit, if any, and compensate with the level of pectin you're adding.

One final note, be sure the pectin is fully hydrated before you cook.

Pate de fruit pectin sold by Chef Rubber is the apple pectin if I'm not mistaken.  If you have a cheaper source of apple pectin just make sure it is the stuff for PDF not for jam as the jam version will not set up as you hope.  

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I'm personally not familiar with apple pectin. But I have run into issues with trying a recipe for pate de fruit from Andrew Schotts' book.  He has his own branded pectin blend specifically for pate de fruit called G Pectin, which I believe is sold at Chef Rubber.

This was discussed over on egullet here: http://forums.egullet.org/topic/97623-what-is-g-pectin/page-2  It's about a third to halfway down the page.

I've had success with Pamona Pectin recipe, which can usually be found in local specialty stores or in bigger places like Sprouts and Whole Foods. The trick is in heating things just right. Too little heat and it'll not set properly, too much heat or too much pectin and it'll be more of a gummy candy. It's been a tried and true go to for me.  

Thank you everyone in advance.

I want to make pate de fruit for two layer pralines.  I've tried a dozen times with 2 recipies and it never sets but I now understand that I need aple pectin, or something.  I see special pate de fruit pectin on Chef Rubber and I'm wondering if it's that worth paying more or will apple pectin be fine?  Is there anywhere cheaper than Chef Rubber for apple pectin?

updated by @greg-gould: 04/10/15 03:36:23