Jam & Jelly Making Tips
Ingredients
Fruit
Fruit is the star of the show here, and the first step to making any sort of preserves is selecting your fruit! While most of the fruit for jam-making should be at the peak of ripeness, the best should be something of a mixed bag. It's far better to have some slightly under-ripe fruit than overripe fruit, because once it goes even a little past its prime, it quickly starts to lose the pectin and acidity that are essential for good jam, while also producing overcooked flavors and a leathery texture. The greener parts contain lots of pectin, acid, and tannin—qualities that will help the jam form a good, jellied texture and taste more complex. Once everything is cooked together, you won't notice the under-ripe berries, since their flavors will blend with the riper berries and balance out.
Sugar
Roles that Sugar plays in making jam:
- Just like salt, sugar acts as a preservative. Sugar bonds with water, drawing moisture out of living cells, thus making the fruit inhospitable to microbes that can cause spoilage. Since water content correlates directly to shelf life, the efficiency of the jelly as a preserving agent depends on its concentration—thicker syrup (aka: a jelly with higher sugar content), typically has less water content and is therefore less perishable. Oh, and sugar also makes preserves deliciously sweet. Although regular table sugar is the typical go-to, other sweeteners like brown sugar, corn syrup, and honey can also be used. The efficiency of the jelly as a preserving agent depends on its concentration—thicker syrup (aka: a jelly with higher sugar content), typically has less water content and is therefore less perishable.
- Aside from preserving the fruit, the sugar in the jam will also help determine its deliciousness, playing a role in both flavor and texture. Too much, and the jam will be unpalatable, the flavors of the fruit replaced with sickly sweetness. Not enough, and the jam will never achieve the proper texture, since fruit does not have enough natural sugar on its own to adequately gel.
- Finally, sugar enhances the strength of the gel by bonding with the water and attracting some of the water away from the pectin, which otherwise would prevent the jam from thickening. In the absence of sufficient water, pectin molecules are more likely to unite with each other. The sugar essentially prevents this water from getting in the way, so what you’re left with is a nicely set jam rather than a thin and runny one.
The sugar-to-fruit ratio in recipes for jam typically ranges from 1:1 to 3:2 (fruit to sugar). Most recipes use a 1:1 ratio, meaning equal weights of fruit and sugar. However, some prefer a slightly higher ratio of sugar, such as 2:1 for sweeter fruits or 3:2 for more tart or acidic fruits. The exact ratio can be adjusted based on the fruit's sweetness, acidity, and pectin content.
Pectin
Pectin is a complex carbohydrate that functions in nature as the structural "cement" that helps hold cell walls together. In solution, pectin has the ability to form a mesh that traps liquid, sets as it cools, and, in the case of jam, cradles suspended pieces of fruit. Since different fruits have varying levels of natural pectin, the type of fruit you use (and its ripeness) will determine the amount of necessary additional pectin. For example, preserves made with apples, quinces, plums, gooseberries, currants and blackberries, which are high in pectin, typically do not need additional pectin, while fruits like apricots, blueberries, and peaches, which are low in pectin, usually do need a little help. Fruits low in pectin are often combined with those high in pectin. Orange (high pectin) and rhubarb jam (low pectin) for instance, blends two fruits with quite different pectin contents.
Note that just-ripe fruit contains the highest pectin levels. When fruit ripens further, its pectin content decreases as pectin turns to pectic acid. Don't be overly impressed by advertisements for "jam berries" that imply that overripe mushy fruit is optimal for preserving. Though in very ripe fruit, flavors are fully developed, pectin is often past its prime. For best results, mix fully ripe fruit, which has the best flavor, with just-ripe fruit, which has the highest gelling power.
Another plus of increasing the pectin in the jam is that it allows the jam to set more quickly so you won't need to cook as long. Long cooking makes for a more muddy jam as the fruit continues to cook.
Acid
Acid, either naturally occurring in fruit or added, is crucial in jam-making for forming a gel network and for preserving the jam. Acid helps extract pectin from fruit during gentle simmering and helps the gelling process, which will not take place unless the mixture is fairly acidic. This means that a bit of lemon, vinegar, or citric acid not only helps to balance your jam's flavor with a little tartness, it also helps create the characteristically spreadable texture of jellies, jams, and marmalades.
Adding acid in the form of fresh lemon or lime juice is important for these reasons:
- First, it makes for a more well-balanced jam, returning some of the acidity lost with the addition of sugar and adding a little tartness.
- Acids are also important in helping the pectin to set. The COOH groups in the pectin are usually ionised, and the negative charges on the molecules this ionisation causes can cause repulsion, and prevent the pectin chains from being able to form the gel network. In water, acid increases the concentration of positive ions. Thus, acid reduces the negative charge on pectin chains, allowing them to bond and form a network that traps water and fruit juices. This network solidifies upon cooling, creating the gel structure of jam. A pH between 2.8 and 3.3 is generally needed for optimal pectin gelling.
- Acid helps extract pectin from fruit during gentle simmering and helps the gelling process, which will not take place unless the mixture is fairly acidic. If fruits (such as apricots) aren't sufficiently tart, a recipe will call for added lemon juice.
- Acid also helps prevent spoilage by lowering the pH (acidic environment), which inhibits bacterial growth. A low pH allows jam to be safely canned in a boiling water bath without the risk of botulism.
Lemon or lime juice is added at the end to preserve its fresh tang and bright citrus flavors. For low-acid fruits, such as sweet cherries, peaches or plums, add 1 tablespoon lemon juice for each pound of fruit or juice to enhance flavor and thickening ability. The exception is tomato jam, which uses 1 tablespoon of vinegar. The ideal pH for pectin gelation is between 2.8 and 3.5— about the acidity of orange juice.
Reducing the Amount of Water
When a jam mixture is cooked, water is removed through evaporation. And when enough water has evaporated, the jam has finally arrived at its gel point. That means the pectin molecules are fully able to stick to each other and form a 3-dimensional web in which the remaining sugary juices are all held like water in a sponge.
The gel point usually corresponds to a specific temperature: the sweet spot tends to be 220°F (8 degrees higher than boiling water). The concentration of sugar at this point is about 65% and the pH is pretty acidic, somewhere between 3.1 and 3.6.
To Summarize
Pectin is what sets, or thickens, jam, but pectin needs partners, namely acid and sugar, to do the job of gelling properly. Sugar boosts the gel-forming capabilities of the jam by drawing water away from pectins, decreasing the ability of the pectin to remain in separate chains, while acid acts as a matchmaker between pectin molecules, allowing it to set up correctly. Acid helps extract pectin from fruit during gentle simmering and helps the gelling process, which will not take place unless the mixture is fairly acidic. Some fruits have enough natural acid so they don’t need any added to the mixture. Other fruits always need added acid. If fruits (such as apricots) aren't sufficiently tart, a recipe will call for added lemon juice.
What is Pectin?
Some fruits, like apples and oranges, have more pectin; some, like strawberries and raspberries, have less. Strawberries, which have very little pectin, will never set into a thick jam on their own—at best, they'll cook to a thickened syrup. Old European methods of jam-making resolve low pectin levels in a berry jam by tossing an apple, quince, or orange into the mix. Some old recipes don't even say to do this, as it was just assumed that a home cook would know as much.
High Pectin Medium Pectin Low Pectn Apples (cooking) Apples (dessert) Elderberries Apples (crab) Blackberries (early) Figs Citrus Fruit Blueberries Grapes Cranberries Greengages Peaches Currents (red, black, white) Mulberries Pears Damsons Raspberries (ripe) Blackberries (late) Gooseberries Raspberries (unripe) Pineapple Plums (sour) Sloes Plums (sweet) Quince Rhubarb Strawberries
It's most concentrated form is in the skin and core of raw fruit.
Using Commercial Pectin
Commercially packaged pectin can be added to fruits low in natural pectin, like apricots, rhubarb, and strawberries. Commercially available pectin powder is often derived from apples, but many other fruits also contain high levels of pectin. If you're using commercial pectin, remember that each jam or jelly recipe is designed to maintain the correct balance between pectin, acid, and sugar for the fruit you're using. If you mess with the proportions, don't expect jam or jelly to set properly.
Low or No Sugar Pectin
Two types of commercial pectins are now available to the home canner: the regular pectin that requires acid and sugar to set in a gel, and the “no sugar pectins” or the “lite” pectin that does not require sugar or acid but does require dextrose or calcium. Called Modified Pectins, these pectins will say “light,” “less sugar” or “no sugar” on the label. Follow the directions on the package. Some of these modified pectin jams and jellies are made with less sugar, while others are made with non-sugar sweeteners and no added sugar.
A "regular" pectin is chemically designed to thicken when combined with heat and sugar. A "low-sugar" pectin undergoes additional refinement to work with lower amounts of sugar. Low-sugar pectins also increase the overall acidity of a jam. They usually contain a small amount of dextrose, which is a hyper-absorptive sugar, and sodium citrate, an acidifier. Using it requires a catalyst, in the form of an acid (from lemon juice) or calcium water. Regular pectin requires no additional catalyst.
From Christina Ward, at Serious Eats:
I love low-sugar pectin, especially the Ball and Sure-Jell brands. It allows flexibility with the type and amount of sugars used. (This includes fruit juices and the artificial sweetener Splenda.) Purists may balk at the idea of adding dextrose and sodium citrate to a jam, but it's the dextrose that ensures sufficiently reduced water activity, important for pectin to form the thickened network, even with lower levels of sugar in the recipe as a whole.
One word of warning: The Pomona's brand of low-sugar pectin works a little differently from Ball and Sure-Jell, relying on calcium water to activate the pectin with little to no additional sugar. The method of incorporating it into a jam is different from other low-sugar pectins, so you can't easily substitute it unless you know how. Even more importantly, Pomona's doesn't really reduce the water activity to a safe level so much as it acidifies the jam. Personally, I don't use Pomona's Pectin because, quite frankly, it makes me nervous. Jam is safely preserved only once we've adequately reduced the water activity; acidification alone doesn't do it.
Many old-school jam recipes require cooking the fruit-and-sugar mixture for a prolonged period of time at 220°F (104°C). This is meant to do two things: reach an 80% water activity (the point at which water activity is reduced enough to prohibit pathogen growth) and get the jam to jell sufficiently. (Candy-makers will recognize that 220°F temperature as just below the "thread" stage.) This is the method used in many European recipes. Here's what's happening: Sugar bonds with the fruit's water molecules, reducing the water activity, while heat evaporates more of the water, further reducing the water activity and causing sugar and carbon molecules to re-chain into tight bunches, which results in thickening. Achieving and maintaining the ideal 220°F temperature requires vigilance and patience. It's a putzy job of stirring, adjusting heat, waiting, and repeating. Those who do use this method should use caution—if you allow your mixture to overheat, the batch can quickly transform into something other than jam. It might turn into candy, or it could just scorch and burn.
The dextrose in commercial pectin, whether regular or low-sugar, provides a scientifically sound shortcut that allows you to avoid that whole process. When you add pectin to your fruit-and-sugar mixture, that dextrose kicks in to rapidly bond with available water molecules, helping you reach your desired water activity almost immediately—no need to cook the jam for a long time to get there. Bringing the mixture to a hard, rolling boil for one minute does the trick and is much easier than the method required if you don't use a commercial pectin.
Using No Pectin
Preserves made with apples, quinces, plums, gooseberries, currants and blackberries, which are high in pectin, typically do not need additional pectin, while fruits like apricots, blueberries, and peaches, which are lower in pectin, usually do need a little help. By adding citric acid or lemon juice to the jam, you are increasing the pectin in the jam which allows the jam to set more quickly. The reason you want your jam to set more quickly is so you don’t have to cook it as long. When you don’t have to cook your jam for long, you will yield more jam. Secondly, when the fruit is cooked less it can maintain more of its shape and more of its freshness of flavor. Fruit cooked for a long time can get rather murky and dull.
It should go without saying that the most important part of the jam-making process is cooking the fruit (since, well, it’s what makes it jam). This is when water evaporates, not only thickening the mixture, but concentrating flavors. Stay alert here: You want that perfect texture — not firm or bouncy, syrupy or pourable. When making jam (or conserve) without added commercial pectin, there are several things you can do to ensure a good set.
- To start, toss your fruit in sugar and let it sit at least 20 minutes before cooking it and up to overnight. This maceration pulls the juices from the fruit, which will dissolve the sugar, jump-starting the jam-making process and preventing clumps of sugar from caramelizing.
- Clip a candy thermometer to the side of the pot and put a small plate in the freezer.
- The jam must then be cooked over high heat in order to evaporate the water as quickly as possible and harness the power of the natural pectin. (Cooking time can vary, depending on a fruit’s water content, but once it’s at a rolling boil, expect to cook it for at least 40 to 50 minutes. Raspberries and blackberries tend to have less water than a strawberry or apple, making them faster to cook.) The high temperature leaves the jam susceptible to burning or scorching at the base of the pot (especially so if you’re using a non-copper pot), so it’s extremely important to stir it constantly once it’s started to thicken even a little. The edges of the pot are most susceptible to this kind of burning, so pay extra close attention there.
- As the jam simmers, a whitish, cloudy foam will most likely form. It’s made up of impurities rising to the top and should be skimmed, as when making chicken stock, to prevent a cloudy or muddy result. Use a fine-mesh strainer or a shallow, wide spoon, and rinse the strainer or spoon between uses to keep the foam from returning to the jam.
- Be patient and stir often. When the jam reaches 220°F, spoon a little bit onto the plate and return it to the freezer for one minute. Drag your fingertip through the jam and tilt the plate from side to side. If the jam stays put and doesn't run, you're good to go. If not, keep simmering and testing. Pectin does continue to gel aa bit as it cools.
No-Pectin Fruit Jam
Summer Blueberry Jam
Christine Ferber
Troubleshooting Tips
My jam is too sweet. Throwing in an extra tablespoon of lemon or lime juice at the end can help, but avoid adding any more than that as it could make the jam runny. Keep in mind that jam will also be sweetest when it’s hot: The flavors (including its sweetness) will mellow once chilled.
My jam won’t set. If you’ve been cooking your jam for the amount of time required and it’s still not setting, cook it a few minutes longer to evaporate some more of the water in the fruit. It’s also important to manage expectations. Some fruit with lower amounts of natural pectin, like strawberries, will never quite reach the same gel-like consistency as those with an abundance of it, like blueberries. As long as it’s no longer syrupy, pieces of fruit swimming in a syrup, you should be all good.
evaporate the water as quickly as possible and harness the power of the natural pectin
so you typically pull fruit preserves off of the stove at the point that they just coat the back of a spoon, running together into a single drop that falls off the end.
Unlike gelatin and agar agar, pectin requires both heat and acid in order to gel.
Skimming the Jam
Testing the Jam
When you think the jam might be close to the perfect texture, you’ll want to test it for doneness. It’s better to find out if the jam is too runny early, rather than once it’s in the jars. To do this, spoon a bit of hot jam onto a chilled plate and drag your finger or spoon through it. How it moves on the plate (or doesn’t) will give you an idea of how thick and jammy (or runny and loose) the jam will be once cooled completely. Typically, it will start to form a gelled skin on top, indicating it’s going to set up. If the chilled jam still seems watery or syrupy, it needs more time to cook.
But always taste and adjust as you go. According to David Lebovitz, the golden ratio to jam-making involves using "3/4 of the amount of sugar" for the fruit you have. The chef provides an example, stating that if you have 4 cups of fruit then you'll need to throw in 3 cups of sugar to ensure your fruit is correctly preserved. And once you've memorized this simple rule, you'll never have to look at a jam recipe again.
Recipe for Homemade Pectin.
This chart shows some of the most commonly preserved fruits, and where they fall in relation to their pectin content and acidity. Bear in mind that most recipes will say if you need to add extra pectin.
| Fruit | Pectin | Acid | Fruit | Pectin | Acid |
| Apples (cooking) | High | High |
Grapes | Low to Medium (Eastern Concord variety High) | |
| Apples (crab) | High | High | Greengages | Medium | |
| Apples (desert) | Medium | Medium | Mulberries | Medium | |
| Apricots | Low | Low | Nectarines | Low | |
| Blackberries (early) | Medium | Peaches | Very Low | Low | |
| Blackberries (late) | Low | Pears | Low | Low | |
| Blueberries | Medium | Low | Pineapple | Low | High |
| Cherries | Low to Medium | Low | Plums (sweet) | Low | Low |
| Citrus Fruit | High | High | Plums (sour) | High | High, especially when slightly underripe |
| Currents (red, black, white) | High | Quince | High | ||
| Cranberries | High | High | Raspberries (ripe) | Medium | |
| Damsons | High | Raspberries (unripe) | Medium | ||
| Elderberries | Low | Low | Rhubarb | Low | High |
| Figs | Low | High (Low?) | Sloes | Medium | |
| Gooseberries | High | High | Strawberries | Low | Low |
- Advantages of making jams and jellies at home - commercial jams and jellies are often cloyingly sweet, because the process by which they extract the juice from the fruit forces them to add pectins that in turn require addition of sugar to make everything jell.
- If fruits are low in pectin then fruits with a higher level need to be added. Alternatively, a few squeezes of lemon juice will help them to set. When possible use slightly underripe fruit when pectin levels will be at the highest.
- Always make sure the sugar is completely dissolved before bringing jam or jelly to a boil. If you don't, the result will be grainy.
- Jelly should be made in small batches. If a larger quantity of juice is used, it will be necessary to boil it longer thus causing loss of flavor, darkening of jelly, and toughening of jelly. It really doesn't work. Trust me; I've tried many times!
- Jelly should be boiled rapidly since long, slow boiling destroys the pectin in the fruit juice.
- Always leave the jam to settle off the heat for 15 mins once setting point is reached to prevent the fruit rising to the surface when poured into the jars.
- Cover the surface of the jam in the jar with a wax disc. This helps prevent mould forming during storage. Seal the jar with a tight-fitting lid or cellophane disc secured with an elastic band. Store in a cool, preferably dark place.
- You can use frozen fruit instead of fresh. Raspberries can be particularly hard to find fresh and are expensive! Frozen fruit work just fine, and measure the same. Just be sure to get the loose, frozen whole fruit; not those that have been mushed up or frozen in a sugar syrup!
- What happens if my jam or jelly doesn't gel? You can recook jam and jelly. You may need to add more pectin, especially if you overcooked it.
