How to Make Sugar Preserves

The term sugar preserve includes a wide variety of sweetened fruit spreads. Achieving the right consistency is a main challenge when sugar preserving.

Foods Suitable for Sugar Preserving

Foods that are commonly sugar-preserved include:

Fruits: Apples, apricots, blackberries, blueberries, cherries, currants, grapes, mangoes, peaches, pears, pineapples, plums, raspberries, rhubarb, strawberries, tomatoes. (After sugar preserving, heat-process these foods using the boiling-water method.)
Vegetables: Beets, carrots, onions. (After sugar preserving, heat-process these foods using the boiling-water method.)

Types of Preserves

There are a variety of sugar preserves that you can make.

Jam: To make jam, whole, chopped, or crushed fruits are cooked with sugar until they are firm but spreadable. Jams are great for beginners because the fruit requires little or no preparation and a wide range of consistencies are acceptable.
Jelly: The trickiest form of sugar preserves to master, jelly is made by straining juice from fruit and boiling it vigorously with sugar until it holds its shape after it cools. Good jelly is clear, bright, firm, and free of fruit pieces.
Marmalade: Marmalades are essentially softer versions of jellies that contain small pieces of fruit or peel. They are cooked in small batches over high heat so that they reach their gelling point quickly.
Preserves: Not to be confused with the overall term for any fruit or vegetable preserved in sugar, preserves are a type of fruit spread made by cooking sliced or diced fruit in a translucent sugar syrup until it just starts to gel. Most preserves are slightly thicker than honey but do not hold their shape on a spoon.
Conserves: Conserves are usually made with a combination of fruits, raisins, and nuts; have a consistency slightly thicker than that of preserves; and are spooned (rather than spread) onto food. Because they often feature ingredients that burn easily, conserves should be simmered slowly over low heat until they reach the desired thickness.
Fruit butter: To make fruit butters, pureed fruits are cooked with spices and a small amount of sugar into a thick, spreadable consistency. Butters are thickened largely via water evaporation and need to be cooked at a low temperature for several hours in a heavy-bottomed saucepan to prevent scorching. Apples and pears are the most common fruits used in butters.

Consistency

When sugar and fruit are cooked together, they form a uniform gel, whose consistency is influenced by a few factors:

Ripeness of the fruit or vegetable
Amount of sugar and acid added
Length of time the mixture is cooked
Amount of pectin in the fruit

Pectin is a substance found naturally in fruits that acts as a thickening agent. All fruits contain different amounts of pectin, and unripe fruits generally contain more pectin than ripe fruits do. Recipes for sugar preserves made from foods naturally low in pectin often call for the addition of store-bought pectin, which comes in both powdered and liquid forms.

If you’re a beginner, always follow sugar preserve recipes to the word, as the ratios of fruit to sugar and ripe to unripe fruit, the cooking time, and the inclusion or omission of citrus peels and commercial pectin all play critical roles in determining the final consistency of your gel.

How to Preserve Using Added Pectin

Recipes for preserving foods that are naturally low in pectin—such as apricots, blueberries, cherries, figs, peaches, pears, raspberries, rhubarb, strawberries, and stone fruits—often call for adding pectin while cooking the fruit and sugar. Be sure to add the pectin in the correct quantity at the proper time. If you overcook store-bought pectin, it will lose its thickening power. Also, swapping liquid for powdered pectin (or vice versa) yields inconsistent results and is not advisable.

How to Preserve Without Using Added Pectin

Fruits such as tart apples, cranberries, citrus, Concord grapes, currants, and plums contain high levels of pectin and can be preserved without adding store-bought pectin. However, since individual pieces of fruit can have different pectin levels depending on their ripeness, preserving without added pectin is an imprecise method that requires a watchful eye during cooking. While many recipes will give approximate cooking times, there are a few methods you can use to gauge your gel’s consistency (see below).

How to Test Preserves’ Consistency

Though all three of the following tests are reliable, as a beginner you should use at least two of them together until you gain a comfort level with preserve making.

Temperature test: The gelling point for most sugar preserves is 220–222°F. Use a candy thermometer to check the temperature of your fruit mixture: submerge the bulb end completely in the fruit and sugar mixture, taking care not to let it touch the bottom of the saucepan. Hold the thermometer upright vertically and bring your eyes level with it to get an accurate reading. For soft gels, stop cooking when the mixture is at 218–220°F; for firm gels, stop at 223–225°F.
Spoon-sheeting test: Dip a cool, stainless steel spoon into the cooking fruit mixture. Lift out a spoonful of the mixture and tip the spoon sideways over a plate. If the mixture has been boiling for only a short time, it will be light and syrupy and drip from the spoon in several places in small droplets. After the mixture has boiled longer, the drips will become larger and will eventually fall off the spoon in sheets. When the mixture starts dropping in heavy sheets, your gel has reached its peak thickness. Further cooking will cause the pectin to break down and your gel to thin out.
Quick-chill test: Before you begin cooking your fruit mixture, put several plates or saucers in the freezer and let them chill for at least 20 minutes. When you’re ready to test the thickness of your cooking mixture, remove the pan from the heat and drop a small amount of gel on one of the chilled plates, put it back in the freezer, and let the gel cool for five minutes. Remove the plate from the freezer and drag your finger through the center of the gel, forming two separate pools. If you’re seeking a soft gel, the two pools should slide back together slowly. For firmer gels, the two pools should stay separate, and the gel’s surface should form small ridges when you drag your finger through it. If the gel is thinner than you’d like and runs back together when you slide your finger through it, cooking it longer will help thicken it further. Unfortunately, there’s no remedy for a gel that’s thicker than you want it to be—you either just have to accept the gel as is or start over. For that reason, it’s advisable to start testing the gel’s consistency even before it looks thick enough to the eye. All preserves thicken slightly when they’re cooled.