Canning & Food Storage

Safe Canning: Where Getting the Numbers Right Matters Most

Canning is one kitchen discipline where precision is a food-safety issue, not just a quality issue. Processing time, jar size, acidity level, and altitude all interact to determine whether home-canned food is safe to eat. The Canning Recipe Scaler adjusts tested recipes for different jar counts — but it never alters the processing time, because tested recipes are validated for specific jar sizes and fill levels. Scaling a recipe doesn't change the heat penetration time.

Altitude Adjustment for Water Bath Canning

Water boils at lower temperatures at altitude. At sea level, water boils at 212°F (100°C). At 5,000 feet, it boils at about 202°F — a 10-degree difference that significantly affects heat penetration. The USDA recommends adding processing time based on altitude: add 5 minutes for 1,001-3,000 ft, 10 minutes for 3,001-6,000 ft, 15 minutes for 6,001-8,000 ft, and 20 minutes for 8,001-10,000 ft above sea level for recipes originally tested at sea level with less than 20 minutes base processing time. The Water Bath Canning Time Calculator builds altitude adjustment in automatically — enter your elevation and it shows the corrected processing time for any jar size.

Jam, Jelly, and Pectin

Pectin type determines the sugar-to-fruit ratio needed for proper gel set. Regular pectin requires high sugar (typically 3:4 fruit-to-sugar by weight). Low-sugar or no-sugar pectin allows more flexibility but requires a different ratio and technique. The Jam Pectin Calculator calculates pectin amounts for any batch size and fruit type, accounting for natural pectin levels in different fruits (apples and citrus are high-pectin; strawberries and cherries are low-pectin and need more added pectin).

Dehydrating and Freeze Drying

Dehydration times vary by food type, thickness, and moisture content. Jerky at 160°F takes 4-8 hours. Apple slices at 135°F take 6-12 hours. Tomatoes can take 8-16 hours. The Dehydrator Time Calculator estimates drying times by food and thickness. Freeze drying takes longer — 24-36 hours for most foods — but preserves nutrition and rehydrates to near-original texture. The Freeze Dryer Batch Calculator plans batch sizes by tray capacity and estimates run time.

Emergency Food Storage

Emergency preparedness guidelines recommend 2,000 calories per person per day as a minimum. A 3-month supply for one adult requires approximately 180,000 calories — roughly 90 lbs of rice, beans, and shelf-stable protein at basic calorie density. The Emergency Food Calculator estimates quantities by person count and storage duration, with shelf-life data for common shelf-stable foods. The Leftover Shelf Life Guide tells you how long cooked food stays safe in the refrigerator or freezer — useful for planning meals to minimize waste.