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Monday, January 17, 2011

Kiwi Fruit Jam

This is one of those jamming projects where I learned a whole lot, sometimes painfully. Two weeks ago, I gave in to temptation and bought a 10 lb. bag of kiwi fruit from a local grower who sells at our farmer's market. While I worried that I wasn't getting to them in a timely manner, two weeks turned out to be just what they needed to ripen and soften.
This is not my first time with kiwi fruit. Last year's jam seemed to hold on to the bright green color a little more. Because I had so much fruit, I prepped the fruit on the evening before jamming day. Perhaps letting the fruit sit overnight changed how it retained color when cooked. I'm not sure, because it looked just the same when I pulled it from the refrigerator. Also, peeling and cutting this fruit for more than an hour led me to discover something else about kiwi - it contains a protein dissolving enzyme called actinidin. Towards the end of my chopping, my left hand really started to sting. I had been chopping the peeled fruit on a chopping board and scooping it up with my left hand to drop in the big measuring cup. Somehow, the knuckles that rubbed across the board upon each scooping ended up bleeding and without a layer of skin. I promise that I did not get any blood in the fruit used for this jam. I found out about the enzyme later when I Googled kiwi fruit trying to figure out why it hurt my skin. Next time I will break out my trusty disposable latex gloves!

One of the challenges with kiwi fruit is that is has quite a bit of air in the cell structures. You can see that it foamed up like crazy. Unfortunately, the foam was well integrated with the fruit chunks and I removed a lot of fruit while trying to remove the foam. I don't generally use the butter trick to keep the foaming down, but I tried it on one of these batches and it didn't help at all.
The other challenge with airy fruit is floating. The jar on the right shows how all the jars looked after coming out of the boiling water bath. After boiling and skimming the jam, I stirred it for several minutes and it looked like the fruit had distributed evenly. However, the BWB left it separated. I did the one thing I know how to do and that is tip the jars a few times as the sealed jars cool. They are still sealed and I think they will be OK. My Internet research has revealed that sometimes floating happens, even when you follow every instruction for every trick in the book. One thing I did learn is that crushing fruit, as opposed to chopping, may help. I did chop these batches, thinking I'd maintain more of the pretty kiwi fruit sun-burst design. The cooked product might as well have been crushed. If I make this again, I will give crushing a try.
The good news is that this weird looking jam is pretty darn tasty. It is tart and the seeds offer an interesting crunch. I keep thinking that maybe it will be good for kids - Frog's Eggs Jam.

I used the cooked jam recipe for strawberries on the Sure Jell low and no sugar variety in the pink box, substituting an equal amount of prepared kiwi fruit for the strawberries. I tested with my litmus strips and confirmed, with online research, that ripe kiwi fruit have a safe PH for water bath canning. They are usually between 3.2 and 3.3. My 10 lbs. of fruit resulted in 16 cups of chopped fruit. I used 6 cups each in two batches, and then used the final 4 cups mixed with crushed pineapple for the Kiwi/Pineapple jam shown in the far left jar in the picture above.

Kiwi Fruit Jam
6 cups chopped (and crushed) ripe kiwi fruit
4 cups sugar
1 package Sure Jell pectin, low or no sugar variety

Prepare boiling water bath, jars and lids. Each batch will make about 7 pints.

In a small bowl, mix the pectin with 1/4 of the sugar. Stir into the fruit. Place the fruit in a heavy bottomed pan and bring to a boil. Watch carefully and stir frequently. When fruit comes to a full rolling boil, add the remaining sugar and stir to combine. Return to boil. Once a full rolling boil has been reached, boil for one minute. Remove from heat and skim away foam. Stir the jam for 2-5 minutes to help distribute fruit. Carefully ladle jam into prepared jars and seal. Process in a boiling water bath for 10 minutes.

I hope your fruit won't float, but if it does, gently turn the sealed jars a time or two as the jam cools. So far, I have had good luck with this and have not lost any seals. If any of you out there knows of some compelling reason not to do this, please let me know!

Now, I have to come up with some recipes that will help me use up the big bowl of froggy-green foam that I skimmed from my batches!


  1. what's the butter trick? If you give me some of this, should i not feed it to my vegan friends?

  2. The butter trick is in the instructions for using Sure Jell. They advise that you can add 1/2 tsp. butter or margarine to try to reduce the foaming. You know I'm a butter gal. I didn't keep the butter batch separated. However, the kiwi-pineapple is vegan.

  3. Thanks for this recipe and tips, I can't wait to try it!

  4. Thank you, Jen. If you give it a try, let me know how it turns out.