1) Practical jam making

Many people have eaten jam, but few have made jam, let alone the making of natural jam without adding any food additive. Through our visit to Red on Tree, we experienced the manufacturing of jam in person, and learned about the making process and preservation principle. It is an interesting learning experience, and we are very lucky to have such an opportunity.

Red on Tree especially arranged a day with the stoppage of production, so that we could experience the making of jam. In the early morning, we arrived at the headquarters of Red on Tree, and put on the full protective clothing, hairnet and mask before entering the production area. Two jam masters in tidy working clothes led us to enter the factory, where there were a lot of equipment, including pots and pans that we often see, as well as machines that we have never seen before. They introduced the making process of jam first, which includes washing, cutting, pickling, cooking, bottling, vacuuming and cooling. They also explained the knowledge and skills to be noted during the entire operation.

We tried to make two types of pineapple jam today because it is now the season for pineapple, and it is relatively easy to make pineapple jam. First, we observed the masters’ demonstration, and then tried to recreate the recipe on our own. During the process, we realized that it is harder than we thought. We had to keep focused on every step.

Cooking was the most difficult part, because the copper pot containing pineapple must be heated continuously on the hot stove. We needed to stir the pineapple in the copper pot constantly until the ingredients were boiled and generated air bubbles. If we were not careful, we would have hurt our hands, or the ingredients would get burnt. The next key step is bottling, which requires “rapid” and “accurate” movements. The mouth of the jar should be cleaned, and then the filled jar should be turned upside down to become vacuumed for jam storage.

During the break while waiting for the bottled jam to cool down, the two jam masters also reviewed the making process and basic knowledge with us with Q&A. We answered all the questions correctly. Finally, we tasted our pineapple jam. Some loved the vanilla flavor pineapple jam, while some loved the Sichuan pepper flavored pineapple jam. The vanilla taste was sweet and mild, while the Sichuan pepper taste was strong and unique. We satisfied our appetite, and packed all the jam that we made and took it all home!

2) Jam Q&A

How is the natural jam made? Is there any secret to cook delicious jam? Are there different cooking methods for different fruits? These questions are answered during our jam making process. In order to strengthen our learning, we held a jam quiz. Each member raised at least one question to form the question list, and then a contest was held. The teacher prepared biscuits as prizes. The following is the summary of our questions, and it is also a small knowledge base of natural jam!

Fruit related

• Q: What type of pineapple is suitable for making pineapple jam?
  A: The local pineapple harvested in the winter season is the most appropriate, because it contains enough acidity.

• Q: Why is there no need to add lemon to pineapple jam?
  A: Fruits with a slight sour taste, such as pineapple, have enough acidity for natural preservation, so lemon is not added.

• Q: Fruits with less pulp need to have additives added, what is considered natural additive?
  A: Apple puree.

Pectin related

• Q: Where does the thick texture of natural jam come from?
  A: The fruit itself generates natural pectin after high-temperature cooking, and besides, rock candy and cane sugar can also contribute to a higher viscosity level in the jam.

• Q: Where does the thick texture of non-natural jam come from?
  A: Gelatin, agar powder.

• Q: When the fruit itself contains less pectin (such as strawberry), what additive can be added to the jam?
  A: The natural pectin additives include apple puree, lemon, kumquat, or the fruit may be soaked in rock candy (in France, the local materials are used, like gluconic acid).

• Q: What is the purpose of adding lemon into the jam?
  A: To add flavor, to increase the pectin level, to reduce the pH value (2.8-3.5), and is helpful for preservation.

Sugar related

Q: How did the sugar used in the fruit pickling evolve?
A: Honey -> cane sugar -> rock candy

Q: What is the proportion between fruit and sugar in jam?
A: 2 kg of fruit to 1 kg of sugar.

Making process related

• Q: Why is the copper pot used to cook jam?
  A: The copper pot has an even heat conductivity, and the jam cooked in a copper pot has a more even deeper color.

• Q: What are the white bubbles generated on the surface during the process of jam cooking?
  A: It is the moisture evaporation and the protein of the destroyed bacteria.

• Q: Explain the sterilization process of jam briefly?
  A: Heat the empty bottle to 300℃ -> immediately pour the boiled jam and fill in the empty bottle -> wipe the bottle mouth with a clean wet cloth ( to prevent mole from growing around the bottle mouth) -> cover the bottle -> turn the jam bottle upside down (helpful to form a vacuum) -> store until the bottle and jam are relatively cooled (form a vacuum naturally) -> put the jam bottle in 100℃ boiling water for 20minutes (this dissolves the overflow jam and sterilize the bottle at the same time)