It’s berry season! I love berries, they’re delicious, and among the most nutritious fruit — high in fiber, vitamin C, antioxidants and anti-inflammatories. Unfortunately, the season is short and they spoil fast.
Jam is a popular way to preserve berries, sadly, when I eat jam, my blood sugar crashes, leaving me needing a nap, but I can eat berries all day long. Why does jam effect me differently?
Let’s take a look at a typical blackberry jam recipe.
- 4 cups of crushed blackberries
- 2 cups of sugar
- Pectin
That’s a lot of sugar! Berries are naturally sweet. Why is so much sugar added? Here’s a little history and science lesson that explains why.
TL;DR; If you just want to make low sugar jam in 15 minutes and don’t care about the history and science, skip down to the recipe.
History
People have been making jam for a long time! The oldest surviving comprehensive cookbook from the Roman world, “De Re Coquinaria” (Latin for “On the Subject of Cooking”) includes a fruit dish made by simmering fruit in honey, that allowed the fruit to be eaten much longer than fresh fruit. This is long before refrigeration, so methods to preserve fruit were very important. By the 9th century, people had learned to preserve fruit using sugar. Slavery during the colonial period, drastically increased the availability and reduced the price of sugar. The lower price and the introduction of pasteurization greatly increased the popularity of jam.
Science
Sugar plays two important roles in jam besides flavor enhancement – preservation, thickening.
The usual spoilers – bacteria, yeasts, and molds, like other living things, need water. Honey contains very little water, and sugar binds to water such that the microbes can’t survive. This typically requires 60–65% sugar by weight in the final product.
Low water availability helps jams last, but it’s not the only preservative in jam. Fruit is quite acidic (ph around 3.3). Most bacteria, and molds can’t survive in such an acidic environment. That’s why fermented foods like yogurt, kefir, sauerkraut, and kimchi last much longer than fresh foods.
If sugar isn’t necessary for preservation, that leaves thickening. Sugar combines with pectin that is in most fruit to thicken jam. Think about the difference between stewed fruit and jam. Modern recipes often include pectin extract, to make jam gel enough to be spreadable. The pectin in fruit, including most refined pectins needs a lot of sugar, approximately 50% the weight of the final product, and acidity to gel the way that we are used to. However, in the early 1960s the naturalist Euell Gibbons popularized “Low-methoxyl” pectin which thickens when you add calcium instead of sugar after his diabetic brother began experimenting with it to make jams and jellies with less sugar.
When making shelf stable, with low sugar, it’s important to get the pH low enough and heat process them correctly. The easiest way is to follow a tested recipe. Pomona Pectin has many low sugar recipes available online for free.
Do you really need shelf stable jam? The preservation qualities of jam making were important before refrigeration. But with modern refigerators and freezers, is it really necessary?
If you want to make jam in 15 minues with no added sugar and you don’t care about shelf stability, here’s a jam recipe made with only natural fruit and chia seeds. With no added sugar, or high heat processing, this jam lets the fruit take center stage.
Ingredients
- 1 cup berries
- 3 dates
- 1 teaspoon chia
- 1 teaspoon lemon juice
Instructions
- Chop dates (and berries if they’re large like strawberries).
- Simmer dates and berries over low heat until the fruit breaks down and becomes syrupy, 5 to 10 minutes.
- Mash the fruit with a potato masher.
- Adjust for sweetness and acidity. Add lemon juice and/or sweetner.
- Stir in chia seeds (grind them first for smoother texture) into fruit.
- If it’s too thick, you can add some water. If it’s too thin, you can cook it down, or add more chia seeds.
This will keep in the refrigerator for about a week, or months in the freezer.