I have a crab apple tree, but never made jelly. I would love to see a recipe. I hate wasting all those little fruits. I recently (well, in July) made stone fruit jelly from cherries, plums, nectarines and apricots.
Made with sugar but no pectin. Came out delicious but it only made 2 jars. One for us and one for BIL and his wife. I'd call it a "limited edition."

The recipe we're using comes from the book So East to Preserve by the Cooperative Extension Service of the University of Georgia. It's a great, informative book; I picked up at the used book store for $1.

The recipe "for 5-6 half-pint jars" is...

4 cups crabapple juice (3 lbs. crabapples + 3 cups water)
4 cups sugar

Prepare juice - Select firm, crisp crabapples, about 1/4 firm ripe and 3/4 fully ripe. (Ours are all firm ripe.)

Sort, wash, and remove stem and blossom ends; do not pare or core. Cut crabapples into small pieces. (Our are tiny; we left them whole). Add water, cover and bring to boil on high heat. Reduce heat and simmer for 20-35 minutes, or until crabapples are soft. Extract juice. (We hung the apple mush in a muslin bag and let the juice drip out.)

To make jelly - Sterilize canning jars; heat lids. Measure juice into saucepot. Add sugar and stir well. Boil over high heat to 8 degrees above the boiling point of water for your altitude, (221 for us) or until jelly mixture sheets from spoon.

Remove from heat; skim off foam quickly. Pour jelly immediately into hot canning jars, leaving 1/4 inch headspace. Wipe jar rims and adjust lids.

Process 5 minutes in a Boiling Water Bath.

Every recipe I've seen for jelly says DO NOT double. I'm one to follow instructions.

Ooops. That book title should read So Easy to Preserve.

Nope you shouldn't double the reciepe. Are you using powdered or liquid pectin? I've always used Sure Jell powder. Made crab apple jelly following the recipe in the folder with the Sure Jell and I am sure thinking it made more than what you're getting.
Are you using a food grinder? I am pretty sure I cooked them whole with the blossom ends and all and then we ran it thru the manual grinder and tossed them.

Crab apples probably have enough pectin that you could safely do it but..........if you want to insure success, then don't. You could always just do one after the other...Of course you know that..........

Several years ago we tried to make crab apple jelly. We just washed very well, then boiled the apples skin and all, as ours did not have the blossoms on the ends, just ends ( if you know what I mean), then put them into a old but can buy them vertical colander with the wooden round thing (like they use to use many years ago, got out as much juice as we could, then strained the juice thru cheese cloths. Got nice clear juice but did have trouble having it set up. DO NOT USE SPLENDA!!! Did not taste good and would not set up. Ended up canning the juice and mixing it with other flavors later. Tried using pectin, but with ours did not work. Ours is not a true crab apple, not sure what it is as even the County Ag dept did not know. It is a cross. Now we just enjoy the blossoms, and throw the apples. Even the birds or deer do not eat them
I wish you the best.
Marie

I tried doing a double batch of pepper jelly and it did not work well. It came out sort of "gummy" if that makes sense. I won't try that again altho' it is a pain to make just one little batch at a time.

The problem with Splenda and Equal is these break down into bitter tasting components if heated too high for too long. The secret is too avoid high temperature. Most succesful recipes using these add the sweeteners after high, prolonged cooking is finished and the mix cooled a bit. If it is impractical to do this, then alternate sweeteners must be used or sugar.

Well, from past experience, I would NOT double batch it. Ended up using all of mine for syrup on pancakes and waffles. Not a total waste, but sure wanted that jelly! As a side note, I've always just turned my filled, closed jars upside down on a clean kitchen towel for 10 min. then turned them right side up and they seal well. Never any problems. I've never put them in a hot bath.
Anyway, good luck and enjoy!

Not a good idea to dble the batch-no

you do not have to take off the stems and blossom ends..just cook the full apple,and strain thru the bag

Do NOT ever squeeze the bag with the apples in,just let it drip,otherwise,your jelly will end up cloudy

If you tire of doing it the little batches at a time,then freeze your juice in containers and do it another time