Rehydration Center Tool
Freeze-Dried Food Rehydration Calculator
Work out a starting estimate for how much water to add back, using fresh and freeze-dried weights, or find the net food weight in a sealed package. Everything runs in your browser: no page reloads, no data leaves your device.
Mode 1: Fresh vs Dry Weight
Enter the food's fresh weight and its freeze-dried weight in the same unit. The difference is the approximate water removed and your starting rehydration estimate.
Water Removed
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Fresh minus Freeze-Dried (Calculated Estimate)
Weight Reduction
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Water Removed ÷ Fresh × 100
Dry Yield
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Dry ÷ Fresh × 100
Starting Rehydration Water Estimate
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Starting Estimate, not an exact amount
Mode 2: Package Rehydration
Weighed a sealed pouch? Subtract the packaging to find the net freeze-dried food weight, then optionally apply a water ratio you enter yourself.
Net Freeze-Dried Food Weight
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Total minus bag minus absorber minus other packaging
Optional: Rehydration Ratio
Enter a ratio of water per 1 part dry food (for example 2 means 2 grams of water per 1 gram of dry food) to see an estimated water amount. This is General Guidance or data you enter yourself, never tested laboratory data.
Estimated Water for This Ratio
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General Guidance / user-entered data, not tested data
About These Numbers
Calculated water replacement is a starting point, not always the final recipe. Actual ideal rehydration may differ because of food structure, cooking, fat, sugar, starch, cell damage, evaporation, sauce, desired texture and preparation method. The result is a starting estimate, never an exact amount required.
The note that 1 g of water is approximately 1 mL is a practical kitchen approximation. It does not apply universally to oils, syrups, milk or other liquids, which have different densities, so milliliter results are meaningful for water rehydration, not for every liquid you might use.
How to Use the Results
- Calculated Estimate: every number on this page is derived from the weights you entered. It is a starting point, and your texture check is the final judge.
- Start slightly below: add a little less water than the estimate, especially for grains, meals and anything porous, then adjust upward in small amounts.
- Weigh carefully: accurate fresh and dry weights make the estimate much more useful. For sealed packages, use Mode 2 to subtract the packaging first.
- Record what worked: after you adjust by texture, note your preferred ratio for that food. See the Rehydration Techniques guide for a record template.
- No tested data yet: none of these numbers are tested laboratory results. The Rehydration Data database is honestly empty until real WeFreezeDryIt Lab testing exists in a later stage.
Frequently Asked Questions
How much water do I add to freeze-dried food?
A useful starting estimate is the water removed, which is approximately the fresh weight minus the freeze-dried weight. For practical kitchen calculations, 1 g of water is about 1 mL. The calculator shows this as a Starting Estimate, not an exact amount, and you should adjust by texture.
How does the fresh vs dry weight calculation work?
The calculator subtracts the freeze-dried weight from the fresh weight to find the approximate water removed, then shows the weight reduction percentage and dry yield percentage. The water removed is the starting estimate for how much water to add back, in milliliters for metric units or a clearly labeled fluid-ounce approximation for imperial units.
Key Takeaways
- Water Removed = Fresh Weight minus Freeze-Dried Weight, a Calculated Estimate.
- For practical kitchen math, 1 g of water is approximately 1 mL.
- Subtract bag, oxygen absorber and other packaging to find net food weight.
- The water result is a Starting Estimate, not an exact amount.
- Adjust by texture and record your preferred ratio for next time.