How do I make plum jam?

Tart plums are one of the easiest fruits to set, because they carry enough pectin and acid of their own. The National Center for Home Food Preservation (NCHFP) no-pectin plum jam is 2 quarts chopped tart plums (about 4 pounds), 6 cups sugar, 1 1/2 cups water and 1/4 cup lemon juice, cooked to the gel point, for about 8 half-pints. Damsons have their own recipe with no lemon at all. Italian (prune) plums are another matter: NCHFP lists them among fruits that always need added pectin or acid. This page sorts the plums, gives each tested recipe, and covers processing.

Which plum is in your bowl

NCHFP's pectin and acid sorting separates plums by type [1]:

NCHFP's general information also says "some plums" usually contain enough natural pectin to form a gel [8], which matches the table: it depends on the plum. If you do not know your variety, taste it. A plum that makes you pucker is the tart kind the no-pectin recipes were written for. A sweet, mild eating plum belongs in a pectin recipe.

Tart plum jam without added pectin

From NCHFP, adapted from So Easy to Preserve (2014) [3].

Ingredients: 2 quarts chopped tart plums (about 4 pounds); 6 cups sugar; 1 1/2 cups water; 1/4 cup lemon juice. Yield: about 8 half-pints.

1. Sterilize canning jars.
2. Combine all the ingredients and bring slowly to a boil, stirring occasionally until the sugar dissolves.
3. Cook rapidly to, or almost to, the jellying point: 8 degrees F above the boiling point of water, which is 220 degrees F at sea level. Stir constantly to prevent sticking or burning.
4. Pour hot jam into hot, sterile jars, leaving 1/4 inch headspace. Wipe the rims with a dampened clean paper towel, adjust two-piece metal canning lids, and process in a boiling water canner.

The phrase "to, or almost to" matters. NCHFP reminds you to allow for thickening as jam cools [15], so taking it off at or just short of the gel point avoids a stiff jar. Finding the boiling point on your own thermometer, which corrects for elevation and weather at once, is explained on the temperature test.

Damson plum jam

Damsons have a recipe of their own, with less sugar and no lemon [6].

Ingredients: 5 cups coarsely chopped damson plums (about 2 pounds); 3 cups sugar; 3/4 cup water. Yield: about 6 half-pints.

The method is the same as the tart plum jam [6]: sterilize the jars; combine all ingredients and bring slowly to boiling, stirring occasionally until the sugar dissolves; cook rapidly to, or almost to, the jellying point (8 degrees F above the boiling point of water), stirring frequently as it thickens to prevent sticking or burning; pour hot jam into hot, sterile jars with 1/4 inch headspace; wipe the rims, adjust two-piece lids and process in a boiling water canner. There is no lemon in this recipe; do not add any, and do not leave it out of the tart plum recipe either. Each was tested as written.

NCHFP also publishes damson plum-orange conserve and plum conserve [9]. Conserves are covered on conserves.

Plum jams with added pectin

For sweet or Italian plums, or when you want a predictable set and a short cook, use a pectin recipe. University of Wisconsin Extension gives two [10]:

UW's recipes come with UW's processing chart: 5 minutes in sterilized jars up to 1,000 feet, then 1 more minute for each added 1,000 feet of elevation (UW's own examples: 6 minutes at 1,250 feet, 7 at 2,010) [10]. NCHFP also lists a plum jam with pectin in its recipe index [9].

Plum skins and plum jelly

The tested plum recipes keep the skins. For jelly, NCHFP says plainly not to peel or pit the plums: cut them in pieces, crush, add water, cover, bring to a boil and simmer 10 minutes before extracting the juice [4].

Plum jelly with liquid pectin (NCHFP) [4]: 4 cups plum juice (about 4 1/2 pounds plums and 1/2 cup water), 7 1/2 cups sugar, 1 pouch liquid pectin, for about 7 or 8 half-pints. Sort and wash fully ripe plums and cut them in pieces without peeling or pitting. Crush, add the water, cover and bring to a boil over high heat, then simmer 10 minutes and extract the juice. Measure the juice into a kettle and stir in the sugar. On high heat, stirring constantly, bring quickly to a full rolling boil that cannot be stirred down. Add the pectin, heat again to a full rolling boil, and boil hard 1 minute. Remove from heat, skim off foam quickly, and pour into hot, sterile jars with 1/4 inch headspace.

Plum jelly without added pectin (NCHFP table) [5]: simmer the fruit 15 to 20 minutes with 1/2 cup water per pound, then use 3/4 cup sugar and no lemon for each cup of strained juice. Four cups of juice yield 8 to 9 half-pints. NCHFP's no-pectin jelly method calls for about 1/4 underripe and 3/4 ripe fruit and no more than 6 to 8 cups of juice at a time [5].

Extracting clear juice is covered on extracting juice for jelly. Plums also pair with Concord grapes in USDA's grape-plum jelly, on grape jelly.

Plum jelly can take two weeks to set

Do not judge a plum jelly the next morning. NCHFP notes that some fruit products take up to 2 weeks to set, and names plum jelly as one that may take the longer time [11]. NCHFP also says not to move jellied products for at least 12 hours after making them [11]. Wait the full time before you decide a batch failed. If it is still soft after that, the USDA remake procedure is on jam that didn't set.

Processing plum jam and jelly

The NCHFP plum recipes use this chart, in sterilized jars [3] [4] [6]:

For any process under 10 minutes, NCHFP says to pre-sterilize the jars [12]. Unsterilized jars and their longer chart are on how long to process jam.

Selling plum jam

Every plum is a federal Group II fruit, so plum jam sold under the standard name needs at least 45 parts fruit to 55 parts sugar [2]. The regulation names damson and greengage separately from other plums, and the jelly standard does the same [13]. Plum is also one of the fruits in the federal fruit butter standard [14], so plum butter can be sold under that name if it meets the standard; see apple butter and other fruit butters.

Plum's best partner

Grapes and plums share a season and a jelly. Grape jelly covers Concord grapes, tartrate crystals and the USDA grape-plum jelly.

References

1. National Center for Home Food Preservation, Jellied Product Ingredients, accessed October 2026. https://nchfp.uga.edu/how/make-jam-jelly/jams-jellies-general-information/jellied-product-ingredients/
2. U.S. Code of Federal Regulations, 21 CFR 150.160, Canned fruit preserves and jams (Cornell LII text, current). https://www.law.cornell.edu/cfr/text/21/150.160
3. National Center for Home Food Preservation, Plum Jam without Pectin, adapted from So Easy to Preserve, 6th ed. (2014). https://nchfp.uga.edu/how/make-jam-jelly/jams/plum-jam-without-pectin/
4. National Center for Home Food Preservation, Plum Jelly with Liquid Pectin, June 2005. https://nchfp.uga.edu/how/make-jam-jelly/jellies/plum-jelly-liquid-pectin/
5. National Center for Home Food Preservation, Making Jelly without Added Pectin (Table 2), accessed October 2026. https://nchfp.uga.edu/how/make-jam-jelly/jams-jellies-general-information/making-jelly-without-added-pectin/
6. National Center for Home Food Preservation, Damson Plum Jam without Pectin, adapted from So Easy to Preserve, 6th ed. (2014). https://nchfp.uga.edu/how/make-jam-jelly/jams/damson-plum-jam-without-pectin/
7. Pomona's Universal Pectin, Create Your Own Recipe: Developing or Converting Recipes for Cooked Jam or Jelly Using Pomona's Pectin, modified August 24, 2023. https://pomonapectin.com/?p=21164
8. National Center for Home Food Preservation, General Information on Canning Jams, Jellies, and Marmalades, accessed October 2026. https://nchfp.uga.edu/how/make-jam-jelly/jams-jellies-general-information/general-information-on-canning-jams-jellies-and-marmalades/
9. National Center for Home Food Preservation, Jams & Jellies recipe index, accessed October 2026. https://nchfp.uga.edu/how/make-jam-jelly
10. University of Wisconsin Extension, Ingham, Making Jams, Jellies & Fruit Preserves (B2909), undated. https://iowa.extension.wisc.edu/files/2021/08/Making-Jams-Jellies-Fruit-Preserves-B2909.pdf
11. National Center for Home Food Preservation, Causes and Possible Solutions for Problems with Jellied Fruit Products, accessed October 2026. https://nchfp.uga.edu/how/make-jam-jelly/jams-jellies-general-information/causes-and-possible-solutions-for-problems-with-jellied-fruit-products/
12. National Center for Home Food Preservation, Do I Need to Pre-Sterilize My Jars before Canning?, May 21, 2014. https://nchfp.uga.edu/blog/do-i-need-to-pre-sterilize-my-jars-before-canning
13. U.S. Code of Federal Regulations, 21 CFR 150.140, Canned fruit jelly (Cornell LII text, current). https://www.law.cornell.edu/cfr/text/21/150.140
14. U.S. Code of Federal Regulations, 21 CFR 150.110, Fruit butter (Cornell LII text, current). https://www.law.cornell.edu/cfr/text/21/150.110
15. National Center for Home Food Preservation, Making Jam without Added Pectin, accessed October 2026. https://nchfp.uga.edu/how/make-jam-jelly/jams-jellies-general-information/making-jam-without-added-pectin/