Hard cheese and grated cheese: what two charts print
Updated
Clemson has one line for hard cheese and grated cheese together and does not say which cheeses it means. Pacific Northwest Extension has a group it calls natural, aged cheese (cheddar, Swiss, brick, Gouda, mozzarella and others) with a line for each form. We pair Clemson’s line with two of them: slices or opened packages, and grated Parmesan or Romano. That pairing is our reading.
The charts do not agree in either column, and the refrigerator figures cannot be converted into each other: Clemson counts in weeks and Pacific Northwest Extension in months, and this site only makes the exact conversions between weeks and days and between years and months. In the freezer, Clemson gives one range for both forms, while Pacific Northwest Extension gives grated cheese the shortest window.
| Food | Refrigerator | Freezer |
|---|---|---|
| Hard cheese, slices or opened packages | 6–12 weeks Clemson HGIC1 month PNW 612 | 6–12 months Clemson HGIC6–8 months PNW 612 |
| Grated hard cheese | 6–12 weeks Clemson HGIC1 month PNW 612 | 6–12 months Clemson HGIC3–4 months PNW 612 |
✓ 2 sources checked per row A single figure means both charts print the same time. Red cells show each chart’s figure where they differ; we do not average them.
- Clemson Cooperative Extension, Home & Garden Information Center, Food Storage: Refrigerator & Freezer (HGIC 3522) (revised March 31, 2020) — verified 2026-09-27
- Pacific Northwest Extension (University of Idaho, Oregon State University, Washington State University), Storing Food for Safety and Quality (PNW 612) (revised March 2023), Table 2, p. 12 — verified 2026-09-27
Good to know
- Pacific Northwest Extension also has a line for large pieces, packaged or wax-coated, with a refrigerator figure and nothing in the freezer cell. Clemson has no line for them, so they are left off.
- Pacific Northwest Extension says natural cheeses can be frozen but are likely to turn more crumbly, that thawing in the refrigerator makes crumbling less likely, and that thawed cheese should be used soon.
- Soft cheeses and pasteurized process cheese have their own lines in Pacific Northwest Extension. Clemson’s cheese spreads line uses a different name from either, so we did not pair them.
Both charts give these times for best quality and call them guidelines, not hard limits. How the rows are matched: our method. Spotted a row that does not match its chart? Tell us and we will recheck the original.