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Jams in General: Theory of Preparation
Jams with a thick and indulgent texture, balanced with just the right amount of citric acid to intensify the fruit's flavor without overpowering its natural sweetness.
jam
technique
preserve
fruit
dessert
Ingredients
Servings:
4

Ingredients

  • quantity of citric acid to add
  • 3 1-2 g / kg fruit
  • 3 3-4 grs / Kg fruit
  • 4 5 grs / Kg fruit

Ingredients

  • fruits MITJA pectin
  • strawberries (0.5%)
  • blackberries (0.5%)
  • prunes (all others)
  • pear (0.5%)
  • peach (0.5%)
  • very ripe apples
  • very sweet oranges
  • hazelnuts

Ingredients

  • strawberry
  • 5.5%
  • 3.3 - 3.4
  • Yeast 0.5%

Ingredients

  • strawberries
  • 57 57%
  • 2.700 grams (net weight)
  • 240 ml180 ml
  • 1.61 g2.025 grams
  • 4.3 4.725
  • 3.44 3.780
  • 350 g135 grams
  • 1.96 2.160
  • 57 57%
  • 11 g12 grams
  • 48 ml54 ml
  • 3.450 grams

Ingredients

  • Temperature ºC at sea level - in Barcelona - in Premià
  • 60 103.7
  • 62 104.1
  • 64 104.6
  • 66 105,1
  • 68 105.7
  • 70 106.4

Ingredients

  • Low consistency
  • farm
  • green beans
Step-by-step Guide

General Jam-Making Theory of Preparation

  • Attending a workshop at the Museum of Jam in Torent is an excellent way to learn about making homemade jams. This workshop details the preparation process, from selecting the fruits to the final packaging.
  • Refer to the leaflet no. 4-69-H "Fruit Jams" from the Ministry of Agriculture, which provides precise information on the ideal proportions of sugar and fruit, as well as the necessary cooking time to ensure optimal preservation of the jam. Follow the instructions to achieve the proper texture and flavor.
  • At GastronomySolar.com, it is important to use a stainless steel (or clay) pot significantly larger than the volume of the ingredients. This is because, when boiling, the mixture rises considerably and may overflow. Aluminum pots are not used because they react with the fruit's acidity. Always protect the stove with aluminum foil, as spillage during cooking is likely. Cook over medium-high heat until the mixture reaches 105 degrees Celsius, stirring occasionally for about 20-30 minutes.

For a Jam to Turn Out Well, You Must Follow Some

  • Ensure that the concentration of soluble solids, measured at 20ºC, is between 65º Brix and 68º Brix. This will ensure the proper gelification of the jam.
  • Check that the final acidity has a pH between 3.0 and 3.5 to ensure good preservation of the product.
  • Verify that there is a sufficient amount of pectin to gel the sugar. A good ratio will ensure an optimal texture for the jam.
  • Before using them, you must sterilize the jars properly. Submerge them in boiling water for approximately 20 minutes.
  • Before filling them, the jars must be clean and dry. You can dry them in the oven at a low temperature to ensure there is no moisture.
  • Take advantage of the sterilization of the jars to do the same with the funnel you will use to fill them. This will prevent possible contamination.
  • It is advisable to always use new lids to ensure a good seal. Avoid old lids that may be deformed or have signs of rust.
  • The quality of the fruit is crucial for a good jam. It should be at the optimal point of ripeness, but not overripe. It is not appropriate to use overly ripe or damaged fruit, as this will affect the final result.
  • Wash the fruit well before removing the stem, pits, or skin. This will prevent the fruit from absorbing unnecessary water.
  • If you are making jam with stone fruit, it is advisable to reserve the pits and boil them with half a liter of water for 20 minutes. This water will be used to cook the fruit, as it provides natural pectin and flavor.
  • If the preparation includes the skin, it should first be washed with a new stainless steel fiber scrubber to ensure hygiene.
  • If the fruit needs to be peeled, while you peel and cut it, submerge it in a cold water bath with citric or tartaric acid to prevent oxidation and preserve the natural color.
  • Prepare the acid bath with about 15 tablespoons of lemon juice per 1 liter of water.
  • When working with citrus fruits:
  • It is important to remove as much of the white part under the skin of the citrus as possible, except when making bitter orange marmalade, where a little can be left to intensify the flavor.
  • With citrus, we always cook the peel first, separately and without sugar. Bring 1/2 liter of water to a boil and, once boiling, add the peels and let them cook for 5 minutes. Then, strain them and they are ready to start the marmalade.
  • Remove the damaged parts of the fruit before processing it.
  • The initial weight of the fruit for calculating other ingredients will always be the net weight, meaning the cleaned, peeled fruit, without seeds and without damaged parts.
  • Weigh the fruit with a scale and write it down on a piece of paper to ensure you have the correct amount.
  • Always use bottled water for preparation. The amount of water will depend on the quantity the fruit produces during cooking.
  • Generally, 10-15% of the net fruit weight is usually sufficient.
  • When cooking at sea level, a boiling temperature of approximately 104ºC-105 ºC corresponds to a solution with a soluble solids concentration between 65ºBrix and 68ºBrix, which is ideal for jamming. If you are at higher altitudes, like in Cerdanya, this temperature should be around 101ºC.
  • Based on the net weight of the fruit, calculate the necessary weight of sugar.
  • Keep in mind that the fruit already contains between 5.0-10.0% natural sugar in its composition.
  • The sugar will boil in an acidic medium, which will cause it to partially transform into inverted sugar. This conversion prevents the jam from crystallizing, and the optimal amount of sugar that should be inverted is between 35% and 40%.

How to Determine the Pectin Level in a Fruit

  • Take a spoonful of the fruit mixture and let it cool slightly. Place this spoonful into a jar with an airtight lid.
  • Add a tablespoon of alcohol to the jar, seal tightly, and shake vigorously for 1 minute.
  • Stop stirring, let it sit for 1 more minute, and then check the result.
  • If the fruit has turned into a jelly-like consistency, it means it has a high pectin content.
  • If large, soft clumps have formed, it indicates a medium pectin content.
  • If the clumps are very small within the alcohol, it indicates a low pectin content.
  • There are 3 ways to add pectin to the jam.
  • Add commercial powdered pectin.
  • The information on the amount of pectin to add can be confusing; I base my approach on an average between two methods (when I have more information, I will adapt it).
  • The thickening capacity of commercial pectin is expressed in degrees and is often 150 degrees. This means that 1 gram of pectin can gel 150 grams of sugar.
  • The manufacturer usually indicates the dosage on the product, typically about 0.3 grams of pectin for every 1.0-1.5 kg of fruit (approximately 3-4 grams per kilogram of fruit). You need to add the weight of the added sugar to the weight of the sugar provided by the fruit (weight of the net fruit multiplied by the estimated sugar percentage according to the table and divided by 100). This total weight is divided by 150 to obtain the amount of pectin to add. Hence, about 3 grams of pectin for every 1.3 kg of fruit. We multiply the 3 grams by the weight of the net fruit and divide it by 1.3. We average the two values obtained to prepare the jam, adjusting the pectin weight according to the final result.
  • The pectin is incorporated towards the end of the cooking process, mixed with 5 times its weight in sugar and sprinkled over the jam using a sieve. Continue cooking for about 4 minutes until it thickens, then add citric acid and cook for 1 more minute.
  • Adding the cooking juice of fruits rich in pectin: we can prepare homemade pectin with green (slightly unripe) apples and lemon. It requires little effort.
  • Thoroughly wash 1 kg of slightly unripe organic apples (the more acidic they are, the more pectin they will have). Granny Smith variety can be used.
  • Without peeling, cut the apples into quarters.
  • Thoroughly wash 2 lemons and cut them into quarters.
  • Boil the apples and lemons for 45 minutes in 1 liter of mineral water.
  • Strain with a cheesecloth or a clean cotton cloth.
  • Allow all the liquid to drain overnight until the next day.
  • We will obtain a gelatinous liquid that will be our natural pectin.
  • Usage: add about 75 ml per kilogram of fruit.
  • Add it when the jam reaches halfway through cooking, along with the lemon juice.

Note

  • Place two tablespoons of 96º alcohol in a small cup, ensuring the cup is clean and dry beforehand.
  • Add a teaspoon of our pectin to it, stirring gently until it is completely dissolved.
  • If the pectin turns into a thick lump, it means it is strong. Immediately discard the test in the sink to avoid accidentally ingesting it, as pharmaceutical alcohol is dangerous to consume.
  • If the pectin does not form lumps, we can continue reducing the pectin by boiling it for another 30 minutes, stirring occasionally.
  • Mixing the jam fruit with fruits rich in pectin (such as apple): We can also add one apple for every kilogram of fruit, which will provide a certain consistency. If using the apple directly, it is useful to place the apple seeds and the lemon seeds (and also orange seeds, if making orange jam) inside a bag and cook them with the jam to enhance the texture.
  • Natural thickeners: Natural thickeners, such as xanthan gum or agar agar, can also be used to achieve the desired texture.
  • Xanthan: Add approximately 3 grams of xanthan for every 1.5 kg of fruit, and stir well until fully incorporated.
  • Agar agar: Dissolve about 4 grams of agar agar per liter of cold liquid. Add it at the end of the cooking process and allow it to boil for a few minutes while stirring constantly. It thickens as it cools.

Important

  • The cooking time for fruit is difficult to specify, as it depends on the ripeness, acidity, and pectin content of the fruit, as well as the intensity of the heat used. It's important to monitor these factors to achieve the desired texture.
  • As a general rule, the cooking time is usually around 25 minutes in total, but this can vary depending on the type of fruit used. For instance, more watery fruits may require less time, while harder fruits may need more.
  • First, cook the fruit on low heat with the pot covered for about 15 minutes to ensure it cooks evenly. Then, increase the heat and leave the pot uncovered for an additional 10 minutes to allow the excess water to evaporate. Note that for citrus jams, there is a specific procedure detailed separately.

Procedure-1

  • Wash the fruit under cold running water and remove any bruised or damaged parts.
  • If the fruit has seeds, carefully remove the seeds and reserve them for later use.
  • If the fruit is stone fruit, boil the stones with half a liter of water for 20 minutes. Then, strain and measure the resulting liquid; this will be used when boiling the fruit.
  • Weigh the fruit once it is clean and free of stones, and write down the weight on a piece of paper to calculate the necessary sugar.
  • Calculate the amount of sugar you need to add based on the desired sweetness of the jam.
  • Divide the sugar you need to add into three parts to incorporate progressively during the cooking process.
  • Measure 50 grams of sugar and mix it with the pectin. Set this mixture aside for the end of the cooking process.
  • Reserve approximately half of the remaining sugar to add during the first boil.
  • Reserve the other half for the second incorporation.
  • Place the fruit and water to heat on low until it starts to simmer gently.
  • Once it reaches the boil, add the first half of the sugar while stirring constantly to prevent sticking.
  • When it returns to a boil, let it cook on moderate heat for 7 or 8 minutes, continuing to stir.
  • During the cooking process, skim the jam to remove any impurities that may form on the surface.
  • Add the second half of the sugar and continue stirring until it is completely dissolved.
  • Once it returns to a boil, let it cook over moderate heat for another 7 minutes, stirring constantly.
  • Check the temperature with a thermometer. The jam will be ready when it reaches 105ºC at sea level (101ºC if you're in high-altitude areas like the Cerdanya).
  • Add the pectin and sugar mixture, preferably sifted, to avoid lumps, and stir well.
  • Let it boil for an additional 4 minutes to ensure the pectin is completely integrated.
  • Incorporate the lemon juice, stir again, and let it cook for one more minute.
  • Turn off the heat once the jam is ready.
  • Skim again if necessary to ensure a clear and clean final product.
  • Fill the jars with the jam while it is still very hot to ensure a hermetic seal.
  • If you decide to use the method of turning the jars upside down, fill them to the brim without leaving any air space. Ensure that the jam is at a minimum of 85ºC, cover immediately after filling, and turn the jars upside down.
  • If pasteurizing, leave a little space at the top of each jar and allow them to cool with the lid not completely sealed.
  • Once the jam has completely cooled, securely seal the jars for storage.

Procedure-2

  • Make a syrup by placing 1 liter of water and 500 grams of sugar in a saucepan over medium heat, stirring occasionally until the sugar is completely dissolved.
  • Wait for the syrup to thicken. You'll know it's ready when it forms large bubbles and the temperature reaches between 110ºC and 120ºC. This may take a few minutes.
  • Once it has the desired consistency, add the chopped fruit, making sure the syrup completely covers it.
  • Cook the fruit for about 12 minutes on medium-low heat, stirring occasionally to prevent it from sticking to the bottom.
  • If we notice there is too much liquid in the pot, we carefully remove it and reserve it in a jar for potential future use.
  • Use the food processor or hand blender to blend the mixture until a smooth texture is achieved.
  • If the mixture is too thick, add part of the reserved syrup and let it cook for 3 more minutes, adjusting the texture to taste.
  • Now add the pectin mixed with 50 grams of sugar. It is best to use a sieve to sift it in and avoid lumps. Stir constantly.
  • Let it boil for 4 more minutes to ensure the pectin integrates well into the mixture, ensuring a good consistency.
  • Next, add the lemon juice, stir well to distribute evenly, and let it cook for 1 more minute.
  • Turn off the heat and remove the pot from the heat immediately.
  • Skim the surface with a spatula or spoon to remove any residual foam.

Procedure-3

  • Place the chopped fruit along with the sugar and lemon juice in a bowl. Let it macerate for about 6 hours to absorb the flavors.
  • After this time, cook the fruit in its own liquid that has been generated during maceration.
  • Let it cook for about 8-10 minutes. The time may vary depending on the type of fruit you are using.
  • Cook the orange peel for about 45 minutes before adding it to the orange fruit. This step will enhance the aroma of the jam.
  • Keeping the pot on the heat, remove the fruit with a skimmer and transfer it to a clean bowl.
  • Continue cooking the syrup for about 15-20 more minutes, until it thickens slightly. If there seems to be too much syrup, you can reserve some in a jar and add it later if necessary.
  • Return the fruit to the pot and let it cook for about 7 minutes. If needed, add some of the reserved syrup.
  • Blend the mixture with the immersion blender until smooth and homogeneous.
  • Now, add the pectin mixed with the 50 grams of sugar, ideally sifted to avoid lumps. Stir constantly.
  • Allow the mixture to boil for an additional 4 minutes to ensure the pectin is well integrated.
  • Add the lemon juice, stir well, and let it cook for 1 more minute.
  • Turn off the heat. The jam will be ready when the concentration of soluble solids is between 65ºBrix and 68ºBrix. You can estimate the Brix degrees by measuring the temperature of the jam with a kitchen thermometer.
  • At sea level, a boiling temperature of approximately 104ºC-105ºC corresponds to a concentration of soluble solids between 65º and 68º Brix. In La Cerdanya, the boiling temperature should reach around 101ºC.
  • If you are not at sea level, you can estimate the 65º-68º Brix concentration by knowing the approximate altitude and consulting a table that relates temperature with altitude and concentration.

Degrees ºBrix - at Barcelona altitude

  • In Premià, we start with a measurement of 60 degrees ºBrix and gradually increase the temperature of the mixture: in La Cerdanya, we consistently maintain temperatures following the series of values: 103.7ºC, 102ºC, 100.3ºC, 98.6ºC, and 96.9ºC.
  • Next, we proceed with another measurement of 62 degrees ºBrix, ensuring that the process continues at 104.1ºC, 102.4ºC, 100.7ºC, 99ºC, and 97.3ºC at the same altitude.
  • In the third stage, we maintain 64 degrees ºBrix and control the temperature at 104.6ºC, 102.9ºC, 101.2ºC, 99.5ºC, and 97.8ºC.
  • Increase to 66 degrees ºBrix, adjusting the temperatures to 105.1 ºC, 103.4 ºC, 101.7 ºC, 100 ºC, and 98.3 ºC.
  • Finish with 68 degrees ºBrix, stabilizing the temperature at levels of 105.7 ºC, 104 ºC, 102.3 ºC, 100.6 ºC, and 98.9 ºC.
  • Conclude the procedure with 70 degrees ºBrix, ensuring a temperature of 106.4 ºC, 104.7 ºC, 103 ºC, 101.3 ºC, and 99.6 ºC.

Other Estimative Procedures

  • Submerge a wooden spoon into the boiling jam. Remove it and let it air until the attached jam cools slightly. Then, tilt the spoon to let the jam drop and observe how it drips. If the last drops are not as liquid and they contract without falling, it's a sign that the final point has been reached or is very close.
  • Take a small amount of the boiling jam and place it on a cold plate or surface. Allow the sample to cool and set to check how it slides when tilting the surface.
  • Take a small sample of the jam with a spoon, let it cool for a few moments, and drop it into a glass of cold water. If the droplets remain whole at the bottom of the glass, it indicates that we are close to the final point. Conversely, if they disintegrate or break, it's a sign that the concentration is still insufficient.
  • The lemons won't be needed until tomorrow when we will use the juice to add at the end of the jam's cooking process.
  • Thoroughly wash the citrus fruits by scrubbing the peel with a new stainless steel fiber scrubber without soap (not one with built-in soap or one that has been used for washing dishes).
  • Peel the oranges or mandarins, ensuring you only remove the skin and leave the white part on the orange (or mandarin).
  • Place the oranges in a bowl of water.
  • Place the peels in another container.
  • Discard any pieces of peel that have black spots.
  • Remove as much of the white pith as possible from the peels.
  • Cut the peels into fine julienne strips.
  • Bring the julienned orange peels to a boil in tap water (this water will NOT be used) over low heat, covered, until they are soft and can be crushed between your fingers (approximately 5 minutes).
  • Reserve everything covered until the next day.
  • Squeeze the orange halves and keep the pulp, juice, and seeds each separately.
  • Store the pulp and juice in the refrigerator until the next day.
  • Place the seeds in a cotton muslin bag that can later be boiled (a beer hop bag, for example).
  • Cook the orange halves (empty and with the pith) and the seed bag with mineral water (this water Will be used) over low heat in a covered pot for 2 hours.
  • Let the pot sit, covered, until the next day.
  • The next day, take a large bowl and check how much it weighs when empty.
  • Add the pulp we have reserved in the refrigerator, the pulp that can be recovered from the boiled orange halves, the peels cut into julienne strips, and the water used to boil the orange halves and seeds. Strain the seed bag to recover the water (and discard the seeds).
  • Do not add the orange and lemon juice yet; it is added towards the end of the cooking process.
  • Measure it, and if it doesn't reach 3 liters, add mineral water. YOU Cannot use the water from boiling the peels.
  • Transfer to the pot.
  • Allow it to simmer on low heat for about 15 minutes until some of the water evaporates.
  • Use an immersion blender to puree the mixture.

With Water

  • A method to eliminate possible air bubbles on the surface is to spray a little clear liquor (rum, gin, vodka, etc.) before sealing the jar. This helps remove air bubbles from the surface.
  • There are two methods to ensure prolonged preservation of the jars: the pasteurization process and inverting the jars upside down.
  • Sterilization with boiling water: a mandatory system for manufacturers and artisans. This technique ensures optimal preservation.
  • Fill the jars leaving a bit of space at the top, approximately 1 cm.
  • Allow one minute for the air to escape and seal the jars tightly with the sterilized lids.
  • Let the jars cool down, and when the glass becomes warm, place them in a pot, separated with kitchen cloths.
  • Fill the pot with cold water until it surpasses the jars by about 3 cm to cover them completely.
  • Place the pot over medium heat and, when it begins to boil, let it boil for 20 minutes.
  • Turn off the heat and leave the jars in the pot until the water is almost cold.
  • Label the jars with the contents and the date of preparation to maintain good control.
  • Upside down: a sufficient method at a domestic level as long as the jars have been filled correctly. Although this method works, I generally prefer to use the other one.
  • With the jam at its hottest (always above 85°C), fill the jars completely to the brim. If we make too many jars, the last ones may cool below 85°C and not pasteurize well.
  • In this case, we must minimize the presence of air inside the jars to ensure good preservation.
  • Letting the jars cool upside down for at least 12 hours ensures an airtight seal.
  • If before sealing the jar we spray a little white liquor (rum, gin, vodka, etc.), any possible air bubbles on the surface are eliminated.
Recommendations & Tricks
  • It is essential to use a stainless steel or clay pot, at least 50% larger than the expected volume of the ingredients, to prevent the jam from spilling over during boiling.
  • Avoid using aluminum pots, as they react with the acidity of the fruit, altering the taste and quality of the jam.
  • Cover the stovetops with aluminum foil before you begin cooking, as jam is prone to spilling, especially at the start of boiling.
  • To achieve jam with good texture and preservation, ensure that the concentration of soluble solids is between 65º Brix and 68º Brix; use a refractometer to measure this.
  • Verify that the pH of the final jam is between 3.0 and 3.5 to ensure its proper preservation and flavor; you can do this with pH indicator paper.
  • Add the correct amount of pectin to ensure good gelification: adjust according to the natural pectin of the fruit used; fruits with Medium pectin require a little more added.
  • Sterilize the jars before using them by boiling them completely submerged in water for about 20 minutes; use clean tongs to remove them and let them air dry on a clean cloth.