When it comes to making my own jam, I find that the fruit often needs something to make it sweeter (perhaps because I buy from a u-pick location and it's difficult to tell when the fruit is at it's peak). By using Pomona's Universal Pectin, I can make my jam with honey or just about any other natural sweetener if I choose, such as stevia. A one ounce box makes about 10 - 12 half pint (8 oz.) size jars, so I was able to use half a box for my six jars of cherry jam. Here's the break down of what I spent (not including jars and equipment since it's assumed you'll reuse them):
Organic Fruit - approximately $8 (I paid $3/lb. and used 4 cups of crushed, pitted cherries)
Natural Pectin (1/2 box) - about $2.25
Lemons (2 for juice) - $1.50
Raw Honey (1 cup) - about $1.92
Total spent: $13.67
Divided between 6 jars = $2.28 each
The Kitchen Calc Pro is great for converting recipes and calculating costs!
At this point, I weighed my jars (and subtracted the weight of the jar itself) and divided the cost per jar by the number of ounces in my jar.
The conclusion: Trader Joe's organic fruit spread cost about $.30 an ounce and my own runs about $.27.
I know exactly what went into my jam, but I also spent time, physical energy, and fossil fuel which isn't included in my final cost.
The bottom line? If you enjoy canning jams, keep doing it. If you watch the price of your fruit, you'll probably break about even with a high end store brand. It really didn't take much time to figure my costs, and you might be able to do a lot better and save more money. It's good information to have when you're working all summer, canning in the kitchen.
Oh, and I'd like to think mine tastes better.