Freeze Drying Safety and Judging Reference
A six-page working reference for Extension volunteers, food-preservation instructors and fair superintendents who are being asked to teach or judge home freeze drying. It is free, there is no email form, and it is written to be copied, excerpted and handed out in class.
Download the PDF — Freeze Drying: Safety, Process and Judging Reference
Rev. October 2026 · 6 pages
Where the authority sits
Stay Fresh Technology builds freeze dryers. We are not a food-safety authority, and nothing in this document should be treated as one.
Every safety statement in it is attributed to the Cooperative Extension or National Center for Home Food Preservation source it came from, with links on the final page, so you can verify it and cite the original directly in your own materials. Where the published sources disagree — and on raw protein they do — we say so rather than quietly picking one. The sections describing machine behaviour come from our own testing and are labelled as such.
What it contains
- What freeze drying does and does not do, including why it is not a kill step
- Why there is no USDA-validated home process yet, and what to judge instead
- The raw-protein disagreement between Utah State and Minnesota Extension, stated plainly
- A food-by-food table: seventeen categories, each with a verdict and the condition attached to it
- Preparation, and determining dryness — the break, cut-and-look and cold-spot checks, plus the weight test
- Packaging, storage and realistic shelf life
- Rehydration and use
- Common failures and what caused them
- A template for setting up a fair class: eight suggested classes, presentation requirements, and a process card to require with every entry
- A draft 100-point score sheet with automatic disqualifiers
- A sources page, all free and citable
For fair boards
As of the 2026 fair books, freeze-dried classes are still rare — most preservation sections list dried fruit, leather, vegetables and herbs only. If you are adding one, you are early, and there is little precedent to copy.
The approach the reference takes is to borrow the dried-foods class template that exhibitors and judges already understand, and add the one thing freeze drying has that dehydrating does not: recorded machine settings. The process card captures shelf chill, target vacuum, maximum shelf temperature and final dry time alongside pre-treatment, dryness test and packaging. An exhibitor who cannot report those settings did not control the process; a judge who has them can explain exactly why an entry scored as it did.
Corrections welcome
If you teach this and something in the reference conflicts with your state's guidance, we would rather hear about it than have it circulate uncorrected. Get in touch and we will fix the next revision. The same applies to fair boards: if you adopt or adapt the class template, we would like to know how it worked.
Background and commentary on the safety points are in our article Freeze Drying Is Not a Kill Step.
Safety guidance in the reference is quoted or paraphrased from Utah State University Extension, University of Minnesota Extension, University of Arizona Cooperative Extension and the National Center for Home Food Preservation, and is not Stay Fresh's own. Please verify against the current edition of each publication before putting it into fair rules or class materials.