Can I Make a Double Batch of Jam or Jelly?


small batch of jelly jars

For those of you who are already canners and jam and jelly makers, you have probably heard or read somewhere that jam/jelly recipes should never be doubled because they will not gel properly. There is also an unwritten rule that adjustments should not be made to those recipes. However, chances are good that no one really explains this complex issue.

It is not recommended for you to either double your recipe or adjust the amount of the ingredients in the recipe. Here’s what could happen:

  • The chance of some batches not setting properly greatly increases.
  • It takes longer to cook.
  • Is more likely to burn.
  • The consistency may be changed.
  • Larger size pots and canner will be required.

However, there is always the exception to the rule. Making a double batch of jam or jelly can actually work. Some people I know do it all the time.

The bottom line is that unless you have years of experience with trial and error, it is just better to stick with single batches of well-tested recipes.

Let’s explore the reasons why this is.

Things that Are Affected by Doubling Jam and Jelly Recipes

  1. Canner
    If you double the jelly recipe, a standard canning pot will probably not hold all the jars at once. For example, a single batch of blackberry jelly will produce approximately 6 jars of jelly. If you double that recipe, you will have approximately 12 jars of jelly, but the standard canner holds only 7 jars. So, you either have to use 2 canners or an extra pot large enough to use for a boiling water bath.
  2. Cooking Time
    If the ingredients are doubled, the jelly will need to be cooked longer, which may cause more evaporation of the liquid and could affect the finished product. Cooking longer when making jam can also result in a rubbery jam, increased chances of burning the batch, and jam that does not set.
  3. The number of jars produced
    Twice the number of jars would need to be prepped for a double batch of jam/jelly.
  4. Size pot used for cooking
    Jelly should be made in a wide pot that does not have tall sides so that the evaporation rate is correct. A tall pot that is smaller in diameter, such as a stockpot, will not cook the jelly properly. The best jelly and jam pot will be the widest pot you have which provides the maximum surface area for faster cooking. Fast cooking produces the freshest tasting jam with the best texture possible. There must be sufficient room in the pot to allow for a full rolling boil. Otherwise, the pot will either overflow or the temperature must be reduced to prevent it from boiling over, which would affect the way the jam/jelly turns out. As a result, if you double the recipe, you must use a larger pot than for the single batch.
  5. Stove
    The standard stove only has 4 burners. You will be using a large pot to make the jelly, a flat pan on one burner to sterilize the jars, a pot to keep the lids in until you need them, and if you need 2 canners or pots for the boiling water bath, I really don’t see how they are all going to fit on your stovetop.

The Role of Each Ingredient:

  • Juice
    Juice provides the flavor and color for your jelly and adds the water or liquid needed as well as part of the required pectin. All types of fruit contain natural pectin, the amount depending on the type of fruit and how ripe that fruit is. Fruit contains the maximum amount of pectin when just ripe, and loses pectin as it continues to mature. Ideally and for the perfect jelly, one-quarter of the fruit will be slightly underripe and three quarters, fully ripe.
  • Sugar
    Acts as a preservative, adds flavor, and aids in the gelling process. Too little sugar will prevent your jelly from gelling and may allow mold to grow. Substitutes such as honey and certain syrups may be used, but this will alter the gel structure and change the taste. Be sure to use recipes for making jelly with alternative sweeteners, don’t just substitute for the sugar in the regular sugared recipe.
  • Pectin
    Forms a gel if in the right ratio with the other ingredients. All fruit contains some pectin, but in different amounts, so if you make jelly without commercial pectin, some fruit would need to be mixed with other high-pectin fruits to gel. Jelly made the old-fashioned way without adding pectin would contain less sugar and would taste fruitier. The easiest and safest way to ensure a good set would be to use my recommended commercial pectin and follow one of the recommended recipes.
    • Ball/Kerr Fruit Pectin – Recommends that you do not double recipe.
    • Pamona Pectin – Instructions say you can double, triple, halve, or quarter all recipes.
    • Using No Commercial Pectin – You would need to use fruit that is high in natural pectin or combine a low-pectin fruit with a high-pectin fruit to get a better gel.  This method requires cooking longer and can affect the color and taste of the jam/jelly.
  • Acid
    Aids in forming a gel if in the proper amount. Some fruits contain acid, but lemon juice can be added to fruits that do not contain a sufficient amount of acid, like blueberries and blackberries. Commercial pectin also contains some acid to aid in gelling.

What Makes Jam/Jelly Gel?

Jelly forms a gel if you use the proper ratio of juice and sugar and pectin and acid. You must have all those ingredients and there must be the right amount of each. All seasoned jelly makers know that you must measure carefully in order to achieve this proper ratio or your jelly may not set properly.

This ratio is actually a scientific approach that forms a gel if accurate. The pectin and acid form the bond that “glues” the sugar and fruit together to form a gel. These pectin bonds trap the fruit molecules forming a thick consistency called gelatinization. Boiling the fruit or juice completes the bond. If undercooked, the bond will not form properly; if overcooked, the resulting product will be too firm.

If you double the jelly recipe, the ratio may not work if all ingredients are exactly doubled as some adjustments might need to be made to achieve this proper ratio. For example, to double recipes that contain hot peppers, you might not want to double the number of hot peppers as it would make the heat of the dish overpowering for some people.

Also, the amount of butter in many cake recipes should not be doubled when you try to double those recipes. It’s the same with jam/jelly; if you change the ratio of the jam/jelly recipe or adjust the amount of the ingredients, that changes the way the ingredients work together to form a gel. It will also affect many other things such as the pot size needed, the number of jars required, the size canner needed, the length of cooking time, and maybe even the required heat source. It may even result in your needing an industrial size stove and pots.

Why Some Fruits Gel Better Than Others

Some fruits gel better than others because they naturally contain higher amounts of pectin and acid. Fruits with more natural pectin and acid gel much better than fruits with low amounts of natural pectin and acid. Also, fruit that isn’t ripe has less pectin and acid than ripe fruit. It contains the maximum amount of pectin and acid when the ripe stage is just achieved. Then, as the fruit continues to ripen, it loses the naturally occurring pectin and acid. Here are a few examples to give you an idea of why some fruits are easier to work with successfully when making jam/jelly:

  • High pectin, high acid
    Crabapples, blackberries, Tart apples, and grapes
  • High pectin, low acid
    Sweet apples, sweet oranges, and tangerines
  • Low pectin, high acid
    Apricots, pineapples, pomegranates, rhubarb, sour cherries, and strawberries
  • Low pectin, low acid
    Blueberries, mangos, nectarines, peaches, pears, and sweet cherries

For more info check out my article on choosing the best fruits for making jam or jelly.

Conclusion

Jelly should always be made in small batches because it will not consistently gel properly if you try to either double the recipe or make larger batches.

Anytime you cook more than 6 to 8 cups of juice at one time, you run the risk of having runny jelly. Jelly is made by using just the right ratio of sugar to juice to pectin to acid in order to gel properly, and when you change those ratios, the gel will often fail.

To put it simply, good jelly making is an art and not a hit-and-miss affair. That art contains some well-researched and well-documented rules and processes that should be strictly followed and observed if you want your jam and jelly to turn out just right.

So, unless you have an industrial stove and industrial size pots, just stick with making small batches to consistently produce a perfect product!

Anne James

Hi, I'm Anne but my grandchildren call me Jelly Grandma. I hope your visit here has been a sweet one.

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