Freezing is a quick and convenient way to make your fruits and vegetables last well past harvest. When you freeze food correctly, it pauses the aging process and delivers fresh flavor, natural color, and a higher nutritional value than other food preservation methods. 

Food will never come out of the freezer in better condition than when it went in. Natural chemical changes occur during the freezing process, resulting in structural changes to fruits and vegetables that can impact the taste, texture, and overall quality. Freezing stops the growth of harmful microorganisms, but once thawed, microorganisms become active and begin multiplying rapidly. Understanding these structural changes and why they occur is a key factor in successfully freezing your garden harvest. 

Read Extension's Guide to Freezing Food and watch this short video on the supplies you'll need for freezing foods.

Selecting Produce for Freezing

Preserving food does not improve its quality, so start by selecting good-quality produce.

• Quality varies among varieties, so choose a variety best-suited for freezing.
• Fruit and vegetables should be free of disease, mold, or insect damage, and not overripe.
• Freeze produce just after harvesting or shortly after purchasing.
• If unable to freeze within 6 to 12 hours of harvest, store in a cool, dry location to minimize deterioration.

How Does Freezing Work?

Water makes up 70 to 90% of the weight of most fruits and vegetables. During the freezing process, water expands, and ice crystals are formed, causing cell walls to rupture. As cell walls rupture, the texture of the food may become softer. This will be more noticeable in vegetables that contain a higher water content and less noticeable in starchy vegetables.

Although water will freeze at 32°F, not all foods will freeze at 32°F. This is because most food contains a combination of many substances, such as air, fiber, sugar, and water.

Types of Freezing

Freezing produce as quickly as possible will result in smaller ice crystal formation. Smaller ice crystals cause less damage to cell walls, resulting in a crispier texture and less liquid being lost when thawed.

Rapid Freezing

Occurs at a temperature of -13°F degrees or less, produces smaller ice crystals, and results in a better quality product. 

Slow Freezing

Occurs at a temperature of -11°F degrees or above, produces larger ice crystals, and results in softer texture and more liquid loss when thawed.

Freeze-thaw Cycle

Occurs when there are fluctuating temperatures, allowing for the growth of ice crystals and further damage to cell walls.