Classic Jam

Equal parts sugar and fruit for real old-fashioned jam

I grew up in England with a yard loaded with fruit and a mother who was a bit of an overachiever in the jam department. Perhaps “overachiever” is the wrong word, since the hundreds of pounds of jam she made did in fact get eaten by our family of six. Store-bought jam was something I experienced only in other people’s houses, and I thought it decidedly inferior. 

Well, watching my mother make jam left me thinking that jam-making was a very big deal, and I was already in middle age before I realized it does not require an enormous copper preserving pan and 20 pounds of fruit. 

In fact, I discovered, it is much, much easier to make jam in small batches using two or three pounds of fruit. The pan should be reasonably wide and just large enough to ensure the jam won’t spit all over your stove top and your hands. I use a six quart stainless steel pan about 11 inches wide. 

It took me a few more years to discover some simple equipment at the hardware store. When I was growing up we were chronically short of money, and my mother never bought anything she didn’t absolutely need. But lo and behold, there are certain inexpensive items that make jam-making much less messy and awkward. Want to get most of the jam in the jam jars? There’s a special funnel for that! Tired of burning or scalding yourself handling hot jelly jars? There are special tongs! 

Although it’s appealing and thrifty to use assorted recycled jars for jam, I’ve given in and now use proper, canning-style jelly jars, which I sterilize in the oven at 225 degrees. The lids and screw-down bands I sterilize in boiling water. I don’t process the filled jars, canning style; I simply fill hot jars with hot jam and screw down the lids while the jam is still hot enough to create a vacuum as it cools. Any jar that doesn’t achieve a vacuum is the one I eat first. Using this method I have only ever had one jar develop mold. 

The one part of jam-making that can be tricky is knowing how long to cook it after you add the sugar so the jam will gel or “set.” The setting agent is pectin, a soluble fiber which occurs in fruit in varying degrees. Apples, currants and stone fruits (apricots and plums) are rich in pectin, as long as they are not over-ripe. Strawberries and raspberries are low in pectin, blackberries and blueberries somewhere in between. 

You can avoid buying commercial pectin by combining low-pectin fruits with high-pectin fruits, or cooking your jam with some apple peels and cores in a cheesecloth bag. My mother made raspberry jam that way.

A good set requires adequate sugar and acid as well as pectin. For low-acid fruit, add lemon juice. For adequate sugar, read “lots of sugar”; classic recipes call for roughly equal weights of fruit and sugar. That’s how you make real jam that will keep for a long time. No, I do not want to hear about “freezer jam” or reduced-sugar “fruit spread.” 

Ah, yes: How do you know you have cooked your jam long enough to set? If you miss the setting point, your jam will become syrup. One old-fashioned test is to dribble a little bit on a cold plate and put it in the fridge. In a minute or two, tip the plate: If the jam is ready, it should stay in place. But how much is a little bit, and how long should it stay in place? Is it ready if it slumps after a few seconds? 

A friend gave me an invaluable tip when she said that in her experience, most jams need only 10 or 15 minutes of boiling to get a good set. You don’t really want it hard as rubber. So start testing after 10 minutes, and if it hangs in there on the plate for a second or two before it moves, you are good. For beginners, it helps to start with something easy like black currants or firm, just-ripe plums.

Rachel Foster lives and gardens in Eugene. She can be reached at

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