Freeze-dried candy has become a popular treat, thanks to its unique texture and intense flavor. This special candy undergoes a fascinating process that leads to its distinct characteristics. One of the most intriguing features of freeze-dried candy is its ability to expand in size after being exposed to air. If you’re curious about why freeze-dried candy expands, read on to explore the science behind this fun and delicious phenomenon.
What Is Freeze-Drying?
Before understanding why freeze-dried candy expands, it’s essential to know how freeze-drying works. Freeze-drying, also called lyophilization, is a preservation process that removes moisture from food while keeping its structure intact. This method involves freezing the candy, then placing it in a vacuum chamber where the pressure is lowered. As the pressure drops, the ice in the candy turns directly into vapor through a process called sublimation, leaving behind a lightweight, porous structure.
This process removes about 98% of the water content from the candy, which contributes to its unique crunchiness. However, freeze-drying also affects the candy’s texture and appearance, making it lighter and more fragile than its non-freeze-dried counterparts.
Why Does Freeze-Dried Candy Expand?
After freeze-dried candy is produced, it has a lightweight, hollow, and airy structure. When exposed to moisture again (like the moisture in the air), it begins to absorb water. This absorption causes the candy to rehydrate, and as the water molecules are absorbed, they fill up the tiny pockets and spaces within the candy, making it expand. This expansion can be seen as the candy “growing” or puffing up when taken out of its sealed package and exposed to the air.
The process is similar to the way sponges absorb water. When the candy begins to rehydrate, the air pockets in the candy’s structure expand as the candy soaks up moisture. This expansion gives the candy a larger volume than it had in its freeze-dried state, but it doesn’t regain its original size or texture because the structure has already been altered during the freeze-drying process.
The Role of Air Pockets
One of the primary reasons freeze-dried candy expands is the presence of tiny air pockets created during the freeze-drying process. These air pockets are essential for the candy’s unique texture. When moisture is introduced, these pockets expand and “inflate” as the candy rehydrates, which makes the candy look bigger and puffier than it did in its original freeze-dried form.
The more porous the candy, the more room there is for air pockets, and the greater the expansion when moisture is added. Some freeze-dried candy, such as fruits or marshmallows, expands significantly due to their high porosity, while other candy types may show only minor expansion.
Why Does Freeze-Dried Candy Shrink Again?
Interestingly, freeze-dried candy doesn’t remain expanded for long. Once the moisture it has absorbed evaporates or is used up, the candy will begin to shrink back to its original size. This is due to the loss of water and the return of the candy to its original state, which involves collapsing the expanded air pockets back into the candy’s structure. However, freeze-dried candy often doesn’t regain its exact size or structure as before, resulting in a less crispy, more chewy or sticky texture.
What Happens to the Flavor?
The freeze-drying process concentrates the flavor of the candy, so even though the texture changes, the taste remains intense. When the candy rehydrates and expands, it doesn’t lose its flavor, but the rehydrated texture may differ. Freeze-dried candy is often described as having a more concentrated, sweet taste compared to its original form.
Conclusion
Freeze-dried candy expands when exposed to moisture due to the porous structure created during the freeze-drying process. The air pockets inside the candy absorb moisture, causing it to rehydrate and puff up. This unique expansion is a hallmark of freeze-dried candy and contributes to its interesting texture. Whether you’re snacking on freeze-dried candy at home or sharing it with friends, the expansion phenomenon adds a fun element to the experience that makes this treat even more enjoyable!