Jam Tutorial

This is a jam tutorial.  No blah, blah, blah, just how to make jam. It is not too late. It is not too hard. There are plums and apples and quinces still in the market, and when all else fails, you can make marmalade using the same method.


• a large pot, the wider the better to allow for maximum evaporation of liquid. This is a traditional jam-making pot. The copper conducts heat well and the sloped sides allow for aforementioned evaporation but you don’t need one like this. I am obsessed, and anyway, I found it at a yard sale. Any large, wide pot will do.

• wooden spoon to stir the jam (so you don’t scratch the bottom of the pot).

• a large metal spoon to test the jam.

• a ladle with which to fill the jars.

• jam jars, lids and screw bands

When you buy jam jars, the whole kit and caboodle is included. You can re-use jars and bands, but must replace lids each time since the rubber rim ceases to be effective in sealing the jar after one use.

• a wide-mouth funnel You could probably manage without one, but it will be a lot messier, and it comes in handy for all sorts of things (pouring a dessert into a fancy stemmed glass dish without totally schmearing the sides, for example)

• a pair of tongs , preferably the kind pictured here,  to make grabbing the jars easier.

The fruit and sugar

Plan to make jam in small batches—use no more than 5 pounds of fruit. Use the best fruit you can find, slightly underripe is best. Why preserve something for later that you don’t even want to eat now?  

Cut the fruit in approximately 1-inch pieces or slices. If you are using berries, wash and pick over them. Discard any that are soft in places. The ratio is: twice as much fruit as sugar by weight

For example, 5 pounds of fruit to 2 1/2 pounds of sugar (2 1/2 pounds =5 cups of sugar).

Lemon juice: always a nice accent, and you can use the zest as well.

Flavors: you can use flavorings like ginger (cook a piece of ginger root with the jam and then discard it) or lavender (infuse the sugar with lavender flowers by chopping them up together in the food processor and leaving them for a day or two, then strain the sugar to remove the lavender bits) or any other herb, like sage or tarragon (cook the jam with sprigs of herbs and then pull them out at the end) but don’t go crazy. Simple is always better.

Pectin: I only use packaged pectin for one jam (raspberry-blueberry) because the fruit has so little natural pectin that it turns out more like a sauce than jam, which would be okay by me but most people I give it to would not be impressed. Otherwise, skip the packaged pectin. It only makes your jam watery and sugary, since it cooks for very little time (not enough for evaporation to take place) and to make it work, you need much too ­much sugar.

Cooking The Jam:

Combine the sugar and fruit in a large pot and slowly bring it to a boil. (The pot should be large enough to allow the jam to boil up, which it will. A lot.) The juice from the fruit will soon combine with the sugar to make a syrup. As soon as that happens, cook over medium heat and let it boil away. When foam rises to the top, ignore it, or if you must, skim it off. 

Stir more as the jam thickens, to keep it from scorching on the bottom, until it reaches the jellying point.

Testing the Jam: This is the trickiest part about making jam: How do you know you’ve reached the jellying point ? I mean, really, really know?  We demand certainty, don’t we? Making jam scares us,because there is no number on a thermometer than can definitely predict this crucial point.

So, before I answer that question, you need an attitude adjustment. You are not seeking perfection. You are seeking some ephemeral essence of summer in a jar that says so much more than that. If you want perfection, go buy some Smucker’s because they make a point of turning out jam that is exactly the same every time. It’s called quality control. It is definitely not the right spirit for this project. 

I said I wasn’t going to do the blah, blah, blah, but bear with me for a second here. You need a certain mindset when you make jam. You have to lighten up and let go, honey! You need to be okay with,  ‘my jam turned out runny so I am going to stir it into yogurt or pour it over ice cream, or drizzle it on toast like honey.’ Or, on the other hand (and I speak from experience),  ‘my jam turned out like a rubbery, impenetrable jar of goop, so I am going to dump it all back in the pot, add water,  heat it again until it boils for a full minute and then put it back in the jars, knowing that I might need to take another trip to the market for some additional lids (sold separately.)’

So here are the telltale signs that your jam is ready, and it is the best that you or I or anyone can do.

It stops streaming off the spoon in a single, thin stream like this:

It starts sheeting off the spoon and the droplets merge, like this:

It looks like this when you put a spoonful on a plate and stick it in the freezer for a couple of minutes and then run your finger through it to make a channel that does not melt back together and the surface wrinkles:

Preserving in a water bath: You can just leave it in the fridge (up to 3 months) or you can put it in a boiling water bath so that you can store it on the pantry shelf for longer. But please, not forever. It kind of loses its sparkle after about a year.

Fill the jars (yes Virginia, clean jars. Why that always needs to be mentioned I don’t know, but now I’m mentioning it. And while I'm on the subject, they don't need to be sterilized first. You will heat and boil the heck out of them later.) Wash them with soapy water and rinse well or just run them through the dishwasher. Leave a 1/4-inch headspace (the space between the top of the jam and the lid.) The contents of the jar will expand as air gets pushed out, so you don’t want to fill the jar to the bursting point.

Wipe the rims with a wet paper towel so they are squeaky-clean. (This protects it from mold.) Place the lids on the jars and screw on the bands, but go easy, cowgirl. You don’t want the jars to explode because you were overzealous about tightening the bands (actually, I’m not so sure this has ever really happened, but just don’t do it.)

Place the jars in a pot of boiling water lined with an old dishcloth to keep them from moving around and crashing into each other and cracking (I’m pretty sure this could have happened to someone.) Be sure the jars are covered by 2 inches of water. Add more boiling water if the water evaporates. Gently boil for 10 minutes. Remove the jars—those fancy tongs come in handy here—and set them on a kitchen towel to cool. You will soon hear the pop-pop-pop of the lid. The little bubble in the center of the jar lid, which you may not have noticed, will now be depressed. But you won’t be. You will be soooooo proud of yourself. And you should be.

Label and date the jars (use a sharpie or a pretty label).

I might have forgotten something. Ask me a question. I’m jam good at jam making, if I do say so. Click to go to recipes for plum jam and peach jam.

Jelly vs. Jam: It must be jelly ‘cause jam don’t shake like that

You make jelly from the juice of the fruit and it is clear and lovely to look at as well as handy to spread on toast. Try it with apples, grapes, quinces or just about any fruit you can think of. The method is similar to making jam insofar as reaching the jellying point and canning is concerned, but you need to cook the fruit with water and then drain it overnight or for several hours through cheesecloth. No cheating. You just have to wait it out or you will have cloudy jam, and then, what would the point be?

Cut the fruit (apples and quinces) or not (grapes, berries). Put fruit in a pot and cover it with water. Cook until the fruit is soft, usually about 20 minutes or so. Line a colander with cheesecloth (or use a jelly bag), set it over a large pot or bowl. Dump the fruit and water into the colander. Let it drip (see above about not squishing or pressing it). 

Combine the juice with sugar in a large pot. The ratio is usually 1 cup juice to 1 cup sugar, though you may be okay with 1 cup juice to 3/4 cup sugar. Cook until it reaches the jellying point and proceed with the boiling water bath.

If reading this makes you tired, than buy some of Bonnie's Jams.

Posted on October 17, 2010 and filed under Breakfast, Canning, Condiments and Jams.