Freeze-drying is the gold standard of food preservation, retaining 97% of nutrients and lasting up to 25 years. However, the biggest frustration for new owners is the waiting game. How long will 10 pounds of strawberries take? Will a batch of milk finish overnight? Overloading your machine or underestimating the cycle time can lead to mushy food or wasted electricity.
Use our Freeze Dryer Batch Calculator to estimate your cycle duration based on machine size, food type, and water content. It also calculates your final “Dry Weight” so you know exactly how many Mylar bags you’ll need for storage.
Freeze Dryer Batch Calculator
How to Use the Freeze Dryer Calculator
- Machine Size: Select your unit (small, medium, large, or XL). This sets the maximum efficient load capacity. Overloading a small machine extends drying time exponentially.
- Food Type: Different foods have different “sublimation difficulties.”
- Fruits (High Sugar): Sugar holds onto water, often requiring longer “Final Dry” times.
- Liquids (Milk/Soup): Contain the most water, requiring extensive sublimation energy.
- Candy: Very fast, as it has low water content and primarily just needs to “puff.”
- Pre-Frozen: The “Secret Sauce” checkbox. Indicate if you have already frozen the trays in a conventional freezer.
Why We Built This: The “Pre-Freeze” Advantage
The “Secret Sauce” of our tool is the Pre-Freeze Logic. A standard freeze dryer cycle has three stages: Freezing, Sublimation (Vacuum), and Final Dry.
The “Freezing” stage can take 4 to 8 hours depending on the food’s starting temperature. By freezing your trays in a standard chest freezer beforehand, you skip this machine phase entirely.
Our calculator visualizes exactly how many hours of runtime (and electricity!) you save by planning ahead.
Educational Guide: Understanding Cycle Times
Freeze drying works by sublimation—turning ice directly into water vapor under a vacuum. This process cannot be rushed.
Factors Affecting Time
- Water Content: 10 lbs of milk contains ~9 lbs of water that must be turned to vapor and collected on the ice reel. 10 lbs of cooked chicken might only have 4 lbs of water. The milk will take significantly longer.
- Slice Thickness: Thinner slices allow water vapor to escape the food’s cellular structure easier. Always slice food no thicker than the rim of the tray (usually 0.5 to 0.75 inches).
- Sugar Content: High-sugar foods (like pineapples or peaches) can melt or “bubble” if the tray gets too warm too fast. The machine manages this by drying slower.
Yield Expectations
Most foods lose 80-90% of their weight during the process.
Example: If you load 10 lbs of raw sliced apples, you will end up with roughly 1.5 lbs of dry chips. Use our calculator’s “Dry Yield” output to prepare your storage containers before the buzzer rings.
Frequently Asked Questions
Q: Why did my cycle take 40 hours?
A: This often happens with “High Liquid” loads like soups or milk, or if the food was sliced too thick. If the food still feels cold to the touch when the cycle ends, it still contains ice inside. Add more dry time.
Q: Does freeze-drying cook the food?
A: No. The trays do warm up slightly (to about 125°F) during the final dry to drive off bound water, but this is not hot enough to cook raw meat. Raw meat must be cooked after rehydrating.
Q: How much does it cost to run a batch?
A: It varies by local electric rates, but a standard medium machine pulls about 10-15 kWh per batch. At $0.15/kWh, a batch costs roughly $2.25 to $3.00 in electricity.
