Pectin: They Key to Great Jam

Other than sweetness, the thing that truly defines jam is its texture. In a perfect universe, that texture is thick yet still slightly soupy, “gel”-like but still very spoonable. Just like grandma used to make. Oh yes, I know that many of the most current recipes encourage cooks to employ packaged pectin until their jam stands up on a plate like a slice of goose liver paté. However a texture that thick not only damages the taste appeal of a jam, it utterly ruins the eye appeal, which to my mind at least is half of the jam-eating experience. A great jam is not just indulgently sweet and fruity, it glistens like crystal on the spoon. Too firm a gel and the result is a cloudy, quivering lump instead of a spoonful of sweet, flowing jewelry…oh mama…

Excuse me…where was I now? Oh yes, pectin. It’s pectin that’s primarily responsible for giving jam its unctuous consistency. Sure, sugar thickens a jam to some extent, but it’s pectin that gives it its loose “gel”. Molecularly, pectin is a carbohydrate (starch) that behaves not unlike gelatin (an animal protein). It’s found in the skin of ripe fruit where it occurs in long, tightly wound bunches. Mashing up fruit and cooking it has the effect of kicking some of these long, kinky molecules free and dispersing them into the fruit juice/sugar solution where they try to hook up again later. Only this time there are other types of molecules between them, so instead of a rigid mass the best they can pull off is a soft, jelly-like pseudo-solid.

Sounds easy right? Well, not entirely, because pectin molecules are slightly fussy things. As they disperse into solution they pick up negative electrical charges, and that makes them want to repel each other rather than bond to one another. The jam maker fixes this problem by adding acid (usually in the form of lemon juice) which neutralizes their charge and makes the molecules want to play nice again. Too much acid damages the pectin molecules, however, so caution must be exercised. Jam makers must also be careful not to employ excessive heat which can, and all too often does, destroy pectin molecules. This is why, after a certain point, no amount of cooking will cause a failed jam to gel. It’s also why, if you heat a mixture with packaged pectin for too long, your jam will still come out runny. But then you’ve got a fresh fruit waffle or ice cream topping…and let’s face it, how bad is that?

So then, how to treat a jam in such a way that you get a great texture without the use of pre-packaged pectin? First and foremost, the answer is to procure a reliable recipe like those in the Ball Blue Book and follow the directions. Second, make sure you have good fresh — or fresh frozen — fruit, since naturally occurring pectin degrades as fruit gets overripe. Heat your jam gently in a broad, shallow pan and only add the acid (lemon juice) after the jam has begun to boil. How to tell when your jam has fully gelled? More on that in the next post.