There are a couple of very different methods of making strawberry freezer jam. The first way is what my grandmother would consider the real way (and the only way that really garners the respect of having made jam) involves cooking berries, lots of stirring, and lots of time. The second way involves fruit pectin and takes about 30 minutes to make, most of the time being spent on cutting the tops off the berries. I make my jam the second way----easy enough I made a batch this morning before making pancakes with fresh strawberries on top and taking the kids to preschool.
To make the quick freezer jam, you need only a handful things and no special tools, except for jars to put the jam in. In my better times, I save jars and lids throughout the year so I don't need to buy any jars. However, in the midst of the move this year, lots and lots of lids got thrown out. I have many interesting looking jars and no lids to match them. If this is your case, or you have no lids, period, you can buy jars at the grocery store. Most grocery stores have tucked away, usually close to the vinegar and on an upper shelf, out of normal view, Mason or Ball 1/2 pint jars, which I find work best for jam.
The most accurate way to make the jam is to buy a box of Sure-Jell or other type of fruit pectin. (To learn more about fruit pectin, click here to read a wikipedia article on it. It is a naturally occurring plant substance). There is a powder form and a liquid form (called Certo by Sure-Jell). On the back of the box, it will tell you exactly what ingredients you need. For the powder, all you need is a lot of sugar, berries, water and the pectin. If you get the Certo, you will also need lemon juice in addition to the ingredients for the powder form. Follow the directions exactly so the jam gels correctly. For 2 c of crushed berries (I use a food processor and try not to puree them, but leave chunks so it is actually jam), you need 4 c of sugar. This is the reason people tend to shy away from fruit pectin as a thickener (vs. cooking to thicken). However, you can buy boxes of Less Sugar fruit pectin which lets you use less sugar. If you use less sugar with regular fruit pectin, you could end up with strawberry syrup instead of strawberry jam. One batch makes 4 half pint jars.
The method varies slightly between the liquid and powder form, but both ways are equally easy. Last year I froze approximately 24 half pints of jam and we used most of it over the year. I know I could have given it as gifts to my in-laws, but by Christmas, I was wondering if we would have enough to make it until the start of strawberry season (we did).
We don't buy much jam in our house, unless we need some raspberry or blackberry jam for a recipe. However, this year, I hope to tackle blackberry jam as well. We'll see about that.