I like to make raspberry jam in the late summer. It’s part of my calendar of the harvest, coming right after peach-oolong jelly and before apple butter. This year I’m trying a batch without the seeds.
Now while I use my handy Kitchen Aid to squish tomatoes, it has no tiny screen that would help me with berries. So I turned to old-fashioned methods: a fine meshed sieve, a big spoon, and elbow grease.
Seedless Raspberry Jam – makes about 7 8-oz jars
- 2 quarts raspberries (just about 2 1/2 lb)
- 6-7 c granulated sugar
- 2-3 Tbsp lemon juice
- a small pat unsalted butter (optional)
Put the raspberries into a heat-proof dish. I found that my 2 quarts fit nicely in a 13×9 Pyrex pan. Put this pan into the oven, uncovered, and set the oven to 225˚F. Leave the berries in for about 30 minutes, because heating the berries gently will make it easier to sieve the stuff.
Prepare your jars and lids as usual; heat water for a boiling-water bath.
Put a fine-mesh sieve over a large bowl or pot, and scoop some of the softened berries into the sieve, and press the pulp and juice through with a big spoon. Do this in several smaller batches, because it’s surprisingly hard work to press the berries through the sieve. You want to end up with only seeds in the sieve, as dry as you can manage. When you’ve pressed out as much as you can, put the seeds in a clean quart-sized jar*, and set aside. Repeat until all the berries have been sieved. Don’t forget to scrape the underside of the sieve with a clean spoon, to get all the pulp off it!
Combine the raspberry pulp with 3/4 its weight in sugar, or just estimate by volume, adding 6 c sugar to the lot, tasting it, and adding a bit more if it’s too tart. Add lemon juice. Heat at a very low setting, and stir until sugar is dissolved. Taste again for balance of sweet and tart; adjust as you wish.
Now add the pat of butter (it helps reduce foaming) and turn heat to high. Bring the jam to a boil, stirring frequently, until the jam thickens and will pass a wrinkle test. Ladle jam into prepared jars, wipe rims, and apply lids and bands. If your last jar is only partly filled, just stick a lid on it and refrigerate.
Process the full jars in a boiling water bath for 10 minutes.
* Oh, wait, you want to know what I do with the seeds in that jar? I add about a half-cup of sugar, and fill the jar with vodka, then cap it, shake to combine, and store in a cool dark cupboard until New Years. Then strain the seeds out, and it’s raspberry cordial!
If you prefer vinegar, omit the sugar and booze, and just top off the jar with white vinegar. Let it stand 3 weeks or so, strain, and you’ve got raspberry vinegar.
Get the Good Stuff! 
Samantha Camp said:
Do you use pectin at all? I’m new at all this lovely canning stuff and just don’t know the difference between using and not using it. Thanks for your help!
mlplouff said:
I rarely use added pectin. Raspberries tend to have enough on their own, and the lemon juice added for flavor and proper acidity helps there too. I do use pectin in my peach-oolong jelly. I will always list it clearly if I add pectin in a preserve.
Rumi O said:
Wondering about the raspberry vinegar. Is it safe to leave in a cool dark place or should I put it in the fridge. Once it’s strained, is it shelf stable or should it be kept in the fridge? Thanks.
mlplouff said:
Yes, the raspberry vinegar keeps at room temperature for up to a year. It’s best kept in the dark – if it’s stored in too much light, the color and flavor will fade.