Simple syrup is a solution made from equal parts sugar and water that is heated until the sugar fully dissolves. It is commonly used to sweeten iced tea, coffee drinks, and cocktails. Some people also use simple syrup to preserve fruit, hoping to extend its shelf life. But does simple syrup actually act as a preservative for fruit?
What is simple syrup?
Simple syrup contains two ingredients – granulated sugar and water. To make simple syrup, the sugar and water are combined in a saucepan and heated over medium heat, stirring frequently, until the sugar fully dissolves. The most common ratio for simple syrup is 1:1 – one part sugar to one part water. However, some recipes call for a richer simple syrup using a 2:1 ratio of sugar to water. The resulting solution contains around 60% to 66% sugar.
Simple syrup has a thick, viscous consistency and a long shelf life due to its high sugar concentration. The high sugar content prevents microbial growth, allowing simple syrup to be stored in the refrigerator for up to a month. Its uses include:
- Sweetening iced tea, coffee, and cocktails
- Adding body and texture to drinks
- Enhancing fruit flavors in desserts and baking
- Making candies and syrups
Does sugar act as a preservative?
Sugar is sometimes used as a natural preservative due to its ability to draw moisture out of microbial cells via osmosis, preventing growth and spoilage. The sugar content of simple syrup makes it seem like it should theoretically help preserve fruit. However, simple syrup on its own does not contain a high enough concentration of sugar to significantly preserve fruit.
Sugar can act as a preservative and extend the shelf life of fruit when it is concentrated into a very high sugar solution. Solutions containing at least 65% sugar Content inhibit microbial growth enough to preserve fruit for months at a time. Some examples of high sugar fruit preservatives include:
- Jams and jellies – Contain at least 65% sugar
- Candied or glacéed fruit – Fruit is cooked in a sugar syrup, allowing it to absorb the high concentration sugar syrup
- Dried fruit – Moisture is removed from fruit, concentrating its natural sugars
On its own, simple syrup only contains about 60% to 66% sugar, below the concentration needed to act as an effective preservative. While simple syrup can extend fruit’s shelf life for a few days, it does not significantly preserve fruit in the long term.
Does simple syrup help preserve cut fruit?
Sometimes people will add simple syrup to cut fruit like sliced peaches, berries, pineapple, or melon, hoping to give the fruit a longer shelf life. Unfortunately, simply coating or soaking cut fruit in simple syrup is not an effective preservation method.
Cut fruit spoils quickly due to exposure to air, damage to plant cell structures, and the release of enzymes that cause deterioration. Simple syrup does not provide enough protection against these spoilage factors. Its sugar content is too low and it does not prevent oxidation.
For cut fruit, more intensive preservation methods are needed, such as:
- Canning – Involves heating cut fruit in jars to kill microbes and enzymes
- Freezing – Prevents microbial growth and enzyme activity
- Drying – Removes moisture to prevent spoilage
- Refrigeration – Slows microbial growth and enzyme activity
Simply submerging cut fruit in simple syrup does not provide the protection needed to significantly extend its shelf life. The fruit still undergoes oxidative browning, making it unappealing within a couple days. Any microbes present when the fruit was cut will still grow over time. Enzymes that cause deterioration are still active. While simple syrup may add a day or two, it does not properly preserve cut fruit.
What about infused simple syrups?
Some people try to make infused simple syrups, where fruit and herbs are cooked directly into the simple syrup to impart flavor. Common combinations include:
- Raspberry simple syrup
- Blueberry thyme simple syrup
- Peach rosemary simple syrup
- Strawberry basil simple syrup
While these infused simple syrups make tasty beverage ingredients, the fruit and herbs added to them are not effectively preserved. These simple syrups still only contain around 60% sugar, far below the sugar concentration needed to act as a preservative. The fruit and herbs begin to deteriorate after a week or two.
To properly extend the shelf life of fruit in syrup, high sugar candied fruit techniques must be used. The fruit must be peeled, pitted, and slowly cooked in a heavy sugar syrup that permeates the fruit flesh with high concentrations of sugar.
What concentration of sugar is needed to preserve fruit?
To significantly extend fruit’s shelf life by months rather than days, very high concentrations of sugar are needed. Some general guidelines include:
- Jams and jellies – 65% to 68% sugar
- Fruit butters – 55% to 65% sugar
- Candied or glacéed fruit – At least 65% sugar
- Dried fruit – Moisture content below 18%
- Fruit juice concentrates – Around 65% sugar
These high sugar levels create an environment where there is not enough moisture to support microbial growth. Enzymes are deactivated. Oxidation is prevented. Exact sugar concentrations depend on the specific fruit’s properties.
Simple syrup only contains 60% to 66% sugar. This is not concentrated enough to achieve true fruit preservation. While simple syrup may help fruit last a few days longer, it does not compare to preservation methods that use adequate sugar, acid, moisture control, and heat to achieve shelf stability.
What are the best ways to preserve fruit?
If you want to properly preserve fresh fruit and extend its shelf life for months at a time, simple syrup alone is not sufficient. Some of the most effective fruit preservation methods include:
Canning
Canning fruit involves placing prepared raw fruit or cooked fruit in sterilized jars, then heating them to kill any microbes and deactivate fruit-spoiling enzymes. This prevents the growth of bacteria, yeasts, and molds. Done properly, canned fruit can last 1 to 2 years stored in a cool, dark place.
Freezing
Freezing fruit slows down chemical reactions that lead to spoilage. Enzyme activity and microbial growth are halted at freezing temperatures while the fruit flesh remains unchanged. Properly frozen fruit can retain quality for about a year.
Drying
Dehydrating fruit removes moisture, making it impossible for bacteria, yeasts, and molds to grow. Enzymes are deactivated. With its moisture levels below 18%, properly dried fruit is shelf-stable for up to a year or longer.
Jam/Jelly Making
High sugar jams and jellies contain at least 65% sugar, as well as fruit juice and pectin. Their sugar content preserves the fruit and gives them long shelf lives. Unopened jams and jellies can be stored for 12+ months.
Fermenting
Fermented fruit products like wine, cider, vinegar, and kombucha use beneficial microbes that produce compounds inhibiting harmful microbial growth. Refrigerated, fermented fruit products can last months.
Unlike simple syrup, these methods alter the fruit’s moisture content, pH, or microbiome to prevent spoilage. Simple syrup alone does not provide enough preservation power. For long term fruit storage, more advanced methods are needed.
Can simple syrup be part of a fruit preservation method?
While simple syrup alone cannot properly preserve fruit, it can play a supportive role when combined with other preservation techniques like canning, fermentation, and refrigeration. Some ways simple syrup can help preserve fruit include:
- Canning syrup – A combination of simple syrup with lemon juice and fruit juice can cover canned fruit. The additional acid and sugar help stabilize canned fruit.
- Kombucha – Simple syrup provides food for the kombucha culture fermenting the fruit.
- Refrigerated storage – Coating berries with simple syrup can help extend their shelf life by a few days when refrigerated.
So while simple syrup should not be solely relied on for fruit preservation, it can play a supportive role when combined properly with other methods that reduce moisture, acidify, add salt, alter the microbiome, or employ refrigeration. On its own though, simple syrup does not contain adequate sugar or provide enough protection to significantly preserve fruit.
Conclusion
Simple syrup is sometimes used in an attempt to preserve fresh fruit or extend its shelf life. However, simple syrup contains only 60% to 66% sugar, below the high concentration needed to properly preserve fruit. Simple syrup does not prevent microbial growth, enzyme activity, or oxidation. While it may extend a fruit’s lifespan by a few days, simple syrup alone cannot compare to preservation methods like canning, freezing, fermentation, and drying when it comes to shelf stability. For significant fruit preservation, more intensive techniques involving moisture control, acidity, and temperature should be used.
Simple syrup can play a supporting role when combined properly with other preservation methods. But by itself, its sugar concentration is too low to create a true preservative effect. So while adding fruit to simple syrup may provide it flavor, the fruit will still deteriorate within a couple weeks. For true long term fruit storage, more concentrated sugar solutions, freeze drying, and canning techniques are needed. Simple syrup alone does not adequately preserve fruit.
