Turn the unset jelly into cactus fruit gummies instead

Be careful of substituting agar or any other "firm" gelling agent; you're likely to end up something closer to Turkish Delight and agar in particular has the property of syneresis (meaning that your gummy candies will dry up fast).

I can think of a few things that would alter the consistency of a gelatin candy/dessert:

• First, it is very important to let the gelatin bloom. When it says to "soften" it in cold water, you need to let it sit there for a good 5 minutes or so until it has absorbed plenty of water and you can actually see a gel forming. Don't stir it at this point!

• All gelatins are not created equal; you need to look at the bloom strength. I think the most common kind in supermarkets is Knox, which has a bloom strength of 225 and is usually what most gelatin recipes calls for. "Platinum" gelatin (normally sold in sheets) goes up to 260, "Gold" is generally around 200, "Silver" is 160, and "Bronze" can be as low as 125 - practically useless for this. If you managed to find powdered gelatin with a bloom strength of under 200, you would need to increase the quantity or else end up with jelly.

• Although gelatin does not require particularly high temperatures to hydrate, you do need to heat the solution to at least 50° C before you set it. If you don't do this, it won't dissolve properly.

• When using powdered gelatin, you're normally supposed to bloom and dissolve it in the same liquid. The recipe you have seems to call for chucking the bloomed gelatin directly into your syrup; this may be deliberate in order to produce some effect I'm not familiar with, but it sounds like an oversight to me. Instead I would heat the gelatin/water solution up to 50° C after blooming (as described above) and then add that to the syrup.

• Finally, as Computerish says, make sure you're heating the syrup solution enough to get all the sugar dissolved, and you might even need to reduce it a little (let it simmer). The more you reduce it, the more viscous the syrup itself will become (at the extreme end turning into pure caramelized sugar, which is rock-hard). So if you're absolutely sure that you are using the gelatin correctly, this would be the next line to pursue. If the syrup is actually syrupy at room temperature then it should form great chewy gummies, but if it's watery then you're more likely to end up with Jell-O.

Fruits that are high in pectin are not necessarily sour and sour fruits are not necessarily high in pectin. However, pectin is typically found in high concentrations in firm fleshed fruit such as apples and in the skins of citrus. Unripe fruit has even more than the ripe. So- I can see why you would come to that conclusion.

It is easy enough to find charts of pectin levels in various fruits.

As you may notice many of these charts list not only fruits high in pectin but those high in acid. This is because acid is necessary to make pectin gel as it removes a charge on the pectin molecules that prevents them from tangling with each other. Low acid fruits, even if they are high in pectin, need extra acid for this reason.

If you are feeling all scientific about it, you can test pectin levels yourself.

There is no danger in experimenting. At least no danger of illness. You might end up with grainy jam if the pectin is too high or syrup if it is too low but it will all taste great.