How Do I Dry Wet Books?

This question heads the list of the most frequently asked questions. There are two basic drying methods: air drying and freeze drying, and each can be done using several techniques.

Air Drying

• This method is most appropriate when only a small number of books (a couple hundred or less) are damp rather than soaking wet, and when indoor temperature, humidity, and air circulation can be controlled.
• Open the books, fan the pages open, and place them on their heads (i.e. with the print upside-down) on a large work table covered with paper. A book should not be positioned on its fore-edge, because the weight of the damp textblock might cause it to pull apart from the binding.
• Use fans to ensure good air circulation. This may take a day or more. Remember that if the books are too wet, mold may grow, thus freezing is the better option.
• Coated papers pose a special problem because the clay coating on their pages will become sticky when wet and will stick together permanently if allowed to dry. Pages should be interleaved with paper towels, blotters, or anything that keeps the coated surfaces from touching one another.
• See Tips for Saving Water-Damage Items for visuals and additional description.

Freezing

• Books can be kept in freezers almost indefinitely. Thus, freezing is particularly useful when a large number of books have gotten wet--they can be taken out and treated in small groups.
• The freezer will not "fix" the books, but if it is done soon after the items are wet, it will prohibit insect infestation or the growth of mold. Freezing buys you time to decide the best course of action for dealing with damaged items.
• Freeze drying can be done in a home or supermarket freezer, but not as effectively as in a freezer specifically designed for large scale and blast freezing.
• If possible wrap the books separately with freezer paper so they will not stick to each other.
• If a home freezer is used, it should have an automatic defroster. Frost-free freezers will eventually help water evaporate out of the paper. Any freezing should be done as soon as possible after the books are damaged.
• Vacuum-freeze drying involves the use of a vacuum chamber, in which a frozen book is placed. The temperature is raised and pressure reduced, causing water in the book to vaporize and it is then sucked out of the chamber.

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