How do I make marmalade that sets and isn't too bitter?

Marmalade sets because citrus peel and pith carry a great deal of pectin, and it turns out bitter mostly because of how much white pith you keep and how you treat the peel before the sugar goes in. Start from a tested recipe, slice the peel thin, simmer it in water until tender and drain it, then cook the peel, fruit and sugar quickly to 8°F above the temperature at which water boils on your thermometer (220°F at sea level). Process the jars in a boiling water canner for the time that matches your elevation and whether you sterilized the jars. This page walks through each of those steps and the choices inside them.

Picking the citrus

Any citrus with a sound, fragrant peel will make marmalade. What changes from one fruit to the next is how bitter the peel tastes, how thick the pith is, and how much juice you get for the work.

Seville oranges are the fruit most UK marmalade recipes are built around. They are a winter fruit with a short window, so if you want them, ask a grocer in late autumn when their supplier expects them. Every other citrus on this list can be bought for most of the year.

US home canning guidance publishes several tested marmalades: the National Center for Home Food Preservation (NCHFP) lists citrus, orange, apple, cranberry, peach-orange and tomato marmalades among its jam and jelly recipes [2]. The method below follows the Citrus Marmalade from the University of Georgia's So Easy to Preserve, as reproduced by UC Master Food Preservers [1].

Where the set comes from

Citrus pectin sits in the white pith (the albedo), the membranes between segments and the seeds. The tested recipe keeps the white layer on the peel strips and says plainly that this is where most of the pectin is [1]. That is why a marmalade without added pectin can set firmly while a jam from the same fruit pulp would not.

The tested recipe also removes the seeds and membrane from the peeled fruit before the pulp is chopped [1]. Many cooks tie seeds and trimmed membrane in a cheesecloth bag and cook them with the fruit for extra pectin, then lift the bag out. That habit comes from older and British recipes rather than from the tested US recipe, so if you use it, treat it as a flavor and texture choice that does not change the recipe's quantities. The deeper story of pectin in peels, cores and seeds lives on where the pectin is.

Making the tested citrus marmalade

The So Easy to Preserve Citrus Marmalade makes about 3 or 4 half-pint jars from one grapefruit, four medium oranges and one lemon [1]. The ingredient list, as reproduced:

• 3/4 cup grapefruit peel (from grapefruit)
• 3/4 cup orange peel (1 orange)
• 1/3 cup lemon peel (1 lemon)
• 1 quart cold water
• pulp of 1 grapefruit
• pulp of 4 medium-sized oranges
• 2 cups boiling water
• 3 cups sugar

The steps:

1. Get the jars ready. Sterilize half-pint jars and prepare two-piece lids by the manufacturer's directions [1]. The 5 minute processing time this recipe uses at low elevation is only valid with sterilized jars (see the processing section below).
2. Cut and simmer the peel. Wash and peel the fruit, then cut the peel into thin strips into a saucepan. The recipe notes that the white membrane on the peel holds most of the pectin, so leave it on when you peel [1]. Cover with the quart of cold water and simmer, covered, until tender, about 30 minutes. Drain [1]. Draining discards the cooking water, and with it some of the bitter compounds the peel releases.
3. Prepare the pulp. Remove the seeds and membrane from the peeled fruit and cut it into small pieces [1].
4. Cook to the set. Combine the drained peel and the fruit with the 2 cups of boiling water and the sugar. Boil rapidly over high heat, stirring often, until the mixture reaches 8°F above the boiling point of water, which is 220°F at sea level. This takes about 20 minutes [1].
5. Skim and fill. Take the pan off the heat and skim. Ladle the hot marmalade into hot, sterile jars, leaving 1/4 inch headspace. Wipe the rims and put on the lids [1].
6. Process in a boiling water canner for the time in the table below [1].

Peel that floats to the top of the jar is a cosmetic problem, and floating fruit has its own fixes.

Hitting the set point at your elevation

Water boils at a lower temperature as you go up, so the set point drops with it. USDA's table gives 220°F at sea level, 216°F at 2,000 feet and 214°F at 3,000 feet [5]. In Boise, at about 2,700 feet, the target sits between those two, at about 215°F. The more reliable approach is the one the recipe itself gives: boil plain water, read your thermometer, and add 8°F [1]. That corrects for elevation, weather and a thermometer that reads high or low all at once. The temperature test page has the full altitude table and the calibration steps.

Marmalade can look runny at the set point because the peel shreds hold syrup between them. Trust the thermometer, or confirm with the cold plate test, rather than cooking on until it looks thick in the pan. Cooking past the set gives a dark, sticky, toffee-like marmalade.

Controlling bitterness

Bitterness in marmalade is a matter of degree, and you control most of it before the sugar goes in.

• Pith thickness. The white pith is both the pectin source and the main source of harsh bitterness. On thick-skinned fruit (navels, grapefruit), shave off some of the pith with a sharp knife and leave a thin white layer on the zest. On thin-skinned fruit, leave it all.
• The simmer and drain. Simmering the peel in water until tender and pouring that water away, as the tested recipe does [1], softens the peel and carries off some bitterness. Peel that goes into the sugar while still firm stays chewy and tastes sharper.
• How thin you cut. Thin shreds give a gentler marmalade; thick-cut peel gives more chew and more bite.
• Which fruit. Seville oranges are bitter by nature, and a Seville marmalade is meant to taste that way. If you want sweetness, use sweet oranges or blend in tangerines.
• Overcooking. Boiling well past the set point darkens the marmalade and turns pleasant bitterness into a burnt edge.

Many British recipes soak the cut peel overnight or simmer the whole fruit for an hour or more before cutting. Those are different methods with different water and sugar amounts. Do not borrow the soak and keep the tested recipe's quantities; pick one method and follow it whole. Why UK recipes differ from US ones, including their oven-sterilized jars and wax discs, is covered on paraffin, inverting jars and other old methods.

Processing marmalade in a US kitchen

Many marmalade recipes you will find are British and skip the canner. A US tested marmalade is processed in a boiling water canner (or an atmospheric steam canner where the recipe allows it), and the time depends on two things: your elevation, and whether you sterilized the jars.

The sterilized row is the recipe's own chart: 5 minutes up to 1,000 feet, 10 minutes from 1,001 to 6,000 feet, and 15 minutes above 6,000 feet, for half-pints or pints [1]. NCHFP says jars processed for less than 10 minutes must be sterilized first, and that unsterilized jars need a full 10 minute process plus the altitude adjustment [6]. The unsterilized row applies the altitude steps from South Dakota State University's water bath chart [7]. Keep each row whole; never put one row's altitude steps on the other's base time. The reasoning, and the 12 minute figure you may see quoted for Boise, are explained on how long to process jam.

In Boise, then, this marmalade gets 10 minutes in sterilized jars or 15 minutes in jars that were only washed and kept hot. Leave 1/4 inch of headspace, and cool the jars undisturbed before you check the seals.

What you can call it

Marmalade has no federal standard of identity. Penn State Extension's commercial primer describes it as made from citrus fruits, including the peel, and notes that conserves, marmalades and spreads have no standards and need no soluble-solids testing [3]. So "Seville Orange Marmalade" is a free name.

The word "jam" is not free. Orange, grapefruit and tangerine are Group I fruits in the federal jam standard [4], so a product sold as "orange jam" must meet that standard's fruit ratio and soluble solids. If you sell, the naming page covers which names carry rules and which do not.

When the marmalade sets too soft or too firm

A marmalade that is still loose after a day or two of cooling usually did not reach the set point, often because the thermometer was off or the pan was crowded. A marmalade that is stiff and dark was cooked past it. Both are fixable or avoidable, and jam that didn't set gives USDA's remake procedure, while jam that's too stiff covers the other direction. If you are planning when to make it, the preserving season calendar puts winter citrus in its place in the year.

References

1. UC Cooperative Extension, Master Food Preservers of Humboldt and Del Norte Counties, Citrus Marmalade (adapted from So Easy to Preserve, 6th ed., 2014, University of Georgia Bulletin 989), undated handout. https://ucanr.edu/sites/Mariposa/files/374819.pdf
2. National Center for Home Food Preservation, Jams and Jellies (recipe index), accessed October 2026. https://nchfp.uga.edu/how/make-jam-jelly
3. Penn State Extension, LaBorde, Food for Profit: Commercial Production of Jams, Jellies and Fruit Butters, updated May 24, 2024. https://extension.psu.edu/food-for-profit-commercial-production-of-jams-jellies-and-fruit-butters
4. Code of Federal Regulations, 21 CFR 150.160, Fruit preserves and jams (Cornell LII), current. https://www.law.cornell.edu/cfr/text/21/150.160
5. USDA and National Center for Home Food Preservation, Guide 7: Preparing and Canning Jams and Jellies, rev. July 2015. https://nchfp.uga.edu/papers/guide/GUIDE07_HomeCan_rev0715.pdf
6. 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
7. South Dakota State University Extension, Kleine and Botzet, A Guide to Water Bath Canning (P-00255), 2022. https://extension.sdstate.edu/sites/default/files/2022-10/P-00255-v2.pdf