You would have to add a few more berries to compensate for the pulp and juice lost in the deseeding process, but not for the seeds.

I would measure the amount of pulp etc lost when deseeding and add that amount of extra berries. If you are measuring seeds and pulp together, add half that amount of extra berries.

How much volume are you losing by removing the seeds? What is the recipe you are using?

Lars

I'm using the raspberry jam recipe from "well preserved."

4 cups raspberries
3 cups sugar
1/4 cup lemon juice

Gently mash berries, add sugar, let set an hour. Boil, add lemon juice, 10-15 minutes (220 degrees). I'm doing 1 1/2 batch because the single batch was so small, and the bigger batch has worked well.

I haven't tried removing seeds yet, so I don't know how much volume I'll lose, but they're pretty seedy.

You do want a similar amount of seedless raspberry pulp because otherwise you are going to get raspberry flavored taffy. I suggest finding a recipe for seedless raspberry jam to start. I mix my raspberries with cherries to make it less seedy, (ripen at the same time), and have seen recipes for blackberries mixed with blueberries or apples. But if you're going for seedless jam, then find a seedless jam recipe. Also, one other problem you may have is that the seeds have some pectin in them, so your jam will be even more runny than before, so you may be tempted to cook even longer getting something like a "butter." You might try to use a pectin recipe with the seedless pulp. But I don't know, I have never made a seedless jam before, just did what I mentioned above, watered it down with something seedless. But now that i have a cool roma mill I may try some this year! Me and my Ball Book of Canning Recipes are separated right now so I can't pass on a recipe, but surely someone here will have it and can advise you. Also might try posting on the Harvest Forum.

I don't know if you are averse to using pectin, but here is a recipe using Pamona's from the North American Raspberry and Blackberry Assn:
Edited by Olychick: the recipe calls for 4 tsp pectin, but the directions call for 4 CUPS of pectin, obviously a typo....
8 cups strained seedless black raspberry pulp
4 teaspoons calcium-water mixture prepared per Pomona's Pectin package
2 Tbsp lemon juice
2 cups sugar
4 teaspoons Pomona's Universal Pectin

Directions:
For Fruit Mixture, combine black raspberry pulp, calcium-water mixture, and lemon juice in a 6-quart or 8-quart stainless steel pot.
In a separate container, combine 2 cups sugar and 4 cups Universal Pectin.
Heat Fruit Mixture slowly to boil. Turn down heat, add Sugar-Pectin Mixture to Fruit Mixture, mix for 2 minutes to dissolve sugar.
Turn up heat (a bit above medium on a gas stove) Bring to good boil, turn off heat.
Fill jars to 1/4 inch from top, apply lids.
Process in hot water bath canner: 10 minutes at sea level, 15 minutes at 5000 ft altitude.
Shelf life one year.

Note from Pete Tallman: Standard supermarket pectin formulas like Sure-Jell don't work with such low sugar percentages. This recipe was developed according to cooked jam recipes from instructions included in Pomona's Universal Pectin, which is available at many natural food stores. See www.pomonapectin.com for list of stores. See Pomona's Universal Pectin recipes for use with alternative sweeteners.

Source:
Peter Tallman, developer of new black raspberry variety "Niwot"

Here is a link that might be useful: Seedless black raspberry jam

This post was edited by olychick on Mon, Jul 7, 14 at 22:08

I liked that recipe because it doesn't use commercial pectin. My first attempt i actually over cooked it and ended up with taffy. However i do have some pectin around I'm not totally averse to using, and it sounds like it makes sense to find the right recipe rather than waste time and materials.

THANKS

I would approach this as if I was making a cross between a jam and a jelly. If I wanted to eliminate the seeds from 1 cup of berries (1 of 6), I would replace it with 1 c of berry juice. To make the berry juice I would take the 1 c of berries and at least 1/4 c water (maybe 1/2 c?) and simmer for a few minutes, then extract the juice and add enough water to total 1c juice. That should put you in the ballpark, because I see your recipe ratio is 3/4 c sugar per cup of fruit, which is the ratio I use for jelly. :) As long as you keep that fruit/juice/sugar ratio correct and bring it to the gel point, it should come out great!

I know I have a seedless jam recipe that I cannot find right now, but the one I did find calls for 2 3/4 lbs berries (1250 g) to 2 1/4 lbs of sugar plus juice of 1 lemon. It is cooked and processed inthe same day. The one that isn't seedless isn't that different in proportions -- 2 lbs or 1000 g berries to 1 3/4 lb or 800 g sugar, but it is macerated overnight and cooks the next day.

I think the seediness might explain why I'm getting such an excessively firm set. I made my third batch yesterday and I'm hoping it's not too firm eventhough I only boiled it a few minutes and it never reached the suggested 218 - 222 degrees. My second batch came out perfect, but my first batch will take some creative uses.

I'm remembering the elderberry jelly recipe that called for boiling the berries before straining the juice to get the natural pectin out of the seeds...

The good thing is I still have 20 cups of rasberries, and bushes that won't quit :) peaches will be in season soon, and I can't wait to try a peach melba jam!

When I do no-pectin jams I always have trouble getting the kind of set I want. I have tried over and over again with my jelly thermometer but it just never gives me good or reliable results. I think those thermometers tend to be inaccurate. Now I always use the cold plate method to test for the jam's setting point, that's the method I have the most luck with.

Use the firm jam for a filling between cake layers, mix it into meringues (saw a strawberry recipe that was only 1 T to 2 egg whites), dissolve into a gelatin salad -- and you can always add a little bit of water to thin it down for a softer jam or even a syrup.