Freeze-Drying Log Sheets with Rehydration Formulas.

Each freeze-dried food, as well as different batches of the same food, will have varying hydration requirements for reconstitution. It depends on the total moisture percentage lost during the freeze-drying process. If you are rehydrating consistency-dependent food and want to ensure proper rehydration, or if you are dividing a tray of freeze-dried food into individual portions, you can use the following formula, once you determine the moisture loss percentage per tray (see the Batch Log Sheets to determine the moisture loss percentage (M).

To determine rehydration (R), per serving, in terms of liquid (in grams):

1. Weigh the dry serving amount going into a jar or bag in grams. This weight = d

2. Determine the original fresh weight of that serving. The fresh weight of the serving = O

Be sure to use the correct “M” calculation per tray, referencing the post-processing calculations on the log sheets. O = d / 1 - (M/100)

3. Calculate the required liquid (in grams) for rehydration or reconstitution per serving. Rehydration (R) where R = O - d

4. Label bags or jars with the Rehydration (R) requirements of liquid, in grams, per serving.

5. It’s also a good idea to include the batch number on your storage package.

If all servings per tray are portioned equally, you only need to calculate “R” once per tray.

Click on the form that matches your freeze-dryer tray count to download.