A complete guide to keeping food safe, delicious, and waste-free. Every technique includes shelf life guidance and safety warnings — because proper preservation is as much about safety as flavour. Browse preservation profiles →
Canning
Canning uses heat to destroy microorganisms and create a vacuum seal. Two methods: water bath canning for high-acid foods (pH below 4.6), and pressure canning for low-acid foods. Never substitute one for the other.
⚠ Safety — Read Before Canning
Botulism (Clostridium botulinum) cannot be seen, smelled or tasted. It grows in low-acid, anaerobic environments — exactly what an improperly canned jar provides.
Always use tested recipes from USDA, Ball, or equivalent authority. Do not adjust ratios or substitute ingredients.
Never use water bath canning for low-acid foods (vegetables, meat, fish, beans). Always use a pressure canner at the correct PSI for your altitude.
Discard any jar with bulging lids, spurting liquid, off-smell, or visible mould — without tasting it.
Always check the seal after cooling: the centre should not flex when pressed. Refrigerate and use within days if the seal fails.
Water Bath — Suitable Foods
Jams, jellies, marmalades
Pickles and relishes (properly acidified)
Fruit and fruit juices
Tomatoes (with added lemon juice or citric acid)
Chutneys (high acid)
Pressure Canner — Suitable Foods
Vegetables (beans, corn, carrots, peas)
Meat, poultry and fish
Soups and stews
Stocks and broths
Mixed low-acid dishes
| Food | Shelf Life (sealed) | After Opening |
|---|---|---|
| Jams and jellies | 1–2 years | Refrigerate, use within 3 months |
| Pickles | 1–2 years | Refrigerate, use within 2 months |
| Canned tomatoes | 12–18 months | Refrigerate, use within 5 days |
| Pressure-canned vegetables | 2–5 years | Refrigerate, use within 3–4 days |
| Pressure-canned meat/fish | 2–5 years | Refrigerate, use within 3 days |
Freezing
Freezing slows bacterial growth by keeping food at or below −18°C (0°F). The safest and most versatile preservation method. Blanching vegetables before freezing stops enzyme activity that causes flavour and texture loss.
⚠ Safety
Never refreeze thawed raw meat or fish without cooking it first.
Thaw in the refrigerator, under cold running water, or in the microwave — never at room temperature.
Freezer burn is a quality issue, not a safety issue — but heavily freezer-burned food should be discarded.
Label everything with contents and date. A full freezer is more energy efficient than a half-empty one.
Best Practice
Blanch vegetables: boil 2–5 minutes, plunge into ice water, dry completely, then freeze
Freeze in single layers on a tray first, then bag — prevents clumping
Remove as much air as possible from bags
Cool all cooked food completely before freezing
Does Not Freeze Well
Lettuce and salad leaves (cell walls burst)
Raw potato (goes grainy — mash or par-cook first)
Whole eggs in shells (expand and crack)
Cream-based sauces (separate on thawing)
Cucumber, radish, watermelon
| Food | Freezer Life (best quality) |
|---|---|
| Beef, lamb, pork (whole cuts) | 4–12 months |
| Minced meat | 3–4 months |
| Poultry (whole) | 12 months |
| Fish (fatty: salmon, tuna) | 2–3 months |
| Fish (lean: cod, haddock) | 6 months |
| Blanched vegetables | 8–12 months |
| Cooked casseroles and stews | 2–3 months |
| Bread and baked goods | 2–3 months |
| Butter | 6–9 months |
Pickling
Pickling uses acid — either vinegar (quick pickling) or naturally produced lactic acid (lacto-fermentation) — to create an environment too hostile for spoilage bacteria. The pH must reach 4.6 or below for safety.
⚠ Safety
Use only vinegar with 5% acidity or higher. Do not dilute beyond tested recipe ratios.
Do not reduce the amount of vinegar or substitute low-acid liquids in tested recipes.
Use pickling or canning salt — table salt with iodine can cause cloudiness and soften pickles.
Quick pickles stored at room temperature must be water-bath canned. Refrigerator pickles are not shelf stable.
Basic Pickling Brine
1 cup white vinegar (5% acidity)
1 cup water
1 tbsp pickling salt
1 tsp sugar (optional)
Bring to boil, pour over packed vegetables
Best Pickling Candidates
Cucumbers, onions, radishes
Carrots, beans, cauliflower
Jalapeños and other chillies
Green mango, raw papaya
Eggs (hard-boiled, brine-pickled)
| Type | Shelf Life | Notes |
|---|---|---|
| Refrigerator pickles | 2–4 weeks | Must stay refrigerated |
| Water-bath canned pickles | 1–2 years | Unopened, cool dark place |
| Pickled eggs | 3–4 months | Refrigerated always |
Fermenting
Lacto-fermentation uses naturally occurring Lactobacillus bacteria to convert sugars into lactic acid. The result is preserved food with enhanced flavour, improved digestibility, and probiotic benefits. Salt is the key — it inhibits harmful bacteria while allowing beneficial ones to thrive.
⚠ Safety
Use non-iodised salt (pickling, sea, or kosher salt). Iodine inhibits fermentation.
Keep vegetables submerged below the brine at all times. Exposed food can grow mould.
White kahm yeast on the surface is harmless — skim it off. Fuzzy pink, black or green mould means discard.
Use the correct salt ratio: typically 2% of the total weight (vegetable + water) for most vegetables.
Ferment in a cool place (18–22°C ideal). High heat speeds fermentation and risks off-flavours.
Classic Ferments
Sauerkraut — shredded cabbage, 2% salt
Kimchi — cabbage, gochugaru, fish sauce or miso
Dill pickles — whole cucumbers in brine
Fermented hot sauce — blended chillies and salt
Beet kvass — raw beetroot in salted water
Signs of Success
Bubbles forming within 24–48 hours
Tangy, sour aroma (vinegary but alive)
Vegetables stay firm and bright
Brine may become cloudy — this is normal
| Ferment | Active Ferment | Refrigerator |
|---|---|---|
| Sauerkraut | 1–4 weeks at room temp | 6–12 months |
| Kimchi | 1–5 days at room temp | 3–6 months |
| Fermented pickles | 3–7 days | 2–4 months |
| Fermented hot sauce | 5–14 days | 6+ months |
Curing & Salting
Curing uses salt, and optionally sugar, nitrates/nitrites, and smoke, to preserve meat and fish by drawing out moisture and inhibiting bacterial growth. One of the oldest preservation methods in the world.
⚠ Safety
Curing salts (Prague Powder / Instacure) contain sodium nitrite and are toxic in excess — use only the precise amounts specified in tested recipes. Never substitute for table salt.
Curing does not replace refrigeration for most products unless you are cold-smoking or making dry-cured products with very low water activity.
Minimum internal temperature for safety: pork 63°C, poultry 74°C, fish 63°C when cooking cured products.
Do not cure at room temperature. Cure in the refrigerator at 1–4°C at all times.
Wet Curing (Brining)
Submerge in salt + water solution (equilibrium brine: 3–5% salt by weight)
Add sugar, herbs, spices, bay leaves
Suitable for: pork belly, whole chickens, fish
Typical time: 24 hours to 7 days depending on size
Dry Curing
Rub cure mix directly onto meat surface
Salt draws out moisture, concentrate flavour
Suitable for: salmon (gravlax), duck, pork
Gravlax: 2 days in fridge under weight
| Product | Refrigerator | Freezer |
|---|---|---|
| Cured salmon (gravlax) | 5–7 days | 2–3 months |
| Brined pork belly (uncooked) | 5–7 days | 6 months |
| Cooked cured meats | 3–5 days | 1–2 months |
Dehydrating
Dehydrating removes water content to below 10–20%, preventing microbial growth. Can be done in a food dehydrator, conventional oven on low, or in the sun in hot dry climates. Creates dried fruits, jerky, herbs, and vegetable chips.
⚠ Safety
Meat and poultry must reach an internal temperature of 74°C during drying to be safe. Pre-cook or post-heat in oven at 160°C for 10 minutes if dehydrator doesn't reach this temperature.
Condition dried food before storing: fill jars loosely, seal, and shake daily for a week. If moisture appears, return to dehydrator.
Store in airtight containers in a cool, dark, dry place. Moisture and light degrade quality rapidly.
Temperatures
Herbs and flowers: 35–40°C
Fruits and vegetables: 55–60°C
Meat jerky: 70–75°C
Oven: lowest setting, door propped open for airflow
Best Dehydrating Candidates
Herbs — basil, thyme, oregano, rosemary
Tomatoes, mushrooms, capsicum strips
Apple, mango, banana, berries
Beef, chicken, venison (jerky)
Citrus zest and slices
| Product | Shelf Life |
|---|---|
| Dried herbs | 1–3 years |
| Dried fruit | 6–12 months |
| Dried vegetables | 6–12 months |
| Jerky (meat) | 1–2 months (room temp), 6 months (refrigerated) |
Vacuum Sealing
Vacuum sealing removes oxygen from packaging, slowing oxidation and inhibiting aerobic bacteria. Extends shelf life 3–5× compared to regular storage. Does not replace refrigeration or freezing but dramatically extends the effectiveness of both.
⚠ Safety
Vacuum sealing does NOT eliminate botulism risk. C. botulinum is anaerobic — it thrives without oxygen. Never vacuum seal garlic in oil without refrigerating immediately and using within a week.
Do not vacuum seal mushrooms, bananas, or soft cheeses at room temperature — seal refrigerated only.
Always label with the seal date. Visual inspection alone cannot determine safety.
| Product | Normal | Vacuum Sealed |
|---|---|---|
| Raw beef (refrigerator) | 3–5 days | 2 weeks |
| Raw fish (refrigerator) | 1–2 days | 4–5 days |
| Cheese (refrigerator) | 1–2 weeks | 4–8 months |
| Dry goods (pantry) | 6–12 months | 2–3 years |
| Meat (freezer) | 6 months | 2–3 years |
Preserving in Oil
Submerging food in oil prevents contact with air and provides a flavour-carrying medium. Commonly used for herbs, garlic, sun-dried tomatoes, roasted peppers, and soft cheeses like feta.
⚠ Safety — Highest Risk
Garlic-in-oil and herb-in-oil preparations at room temperature carry serious botulism risk. Fresh garlic and herbs in oil MUST be refrigerated and used within 1 week.
Commercial products contain acidifying agents specifically to prevent botulism. Homemade versions do not — never store at room temperature for extended periods.
Dried herbs and dried garlic in oil are safer than fresh — moisture is the primary risk factor.
| Product | Shelf Life | Storage |
|---|---|---|
| Fresh herbs in oil | 1 week | Refrigerator only |
| Dried herbs in oil | 1–3 months | Cool dark pantry |
| Sun-dried tomatoes in oil | 2–3 months | Refrigerator once opened |
| Marinated feta in oil | 2–3 weeks | Refrigerator only |
| Confit (duck, garlic) | 1–3 months | Submerged in fat, refrigerator |
Sugar Preserves
High sugar concentrations bind water, making it unavailable to microorganisms. Jams require 60–65% sugar by weight for safe room-temperature storage. Pectin (natural or commercial) creates the gel structure.
⚠ Safety
Reducing sugar significantly below tested recipe amounts creates a product that is NOT shelf stable at room temperature — refrigerate and treat as fresh fruit.
Always use sterilised jars. Fill hot jam into hot jars, seal immediately.
Use a thermometer: jam is ready at 105°C (setting point). Underset jam ferments in the jar.
Pectin Content (Natural)
High pectin: citrus, apples, quince, blackcurrants, gooseberries
Medium: apricots, raspberries, blackberries, plums
Low: strawberries, cherries, pears, figs — add lemon juice or commercial pectin
Types of Sugar Preserves
Jam — crushed or chopped fruit with sugar
Jelly — strained clear fruit juice with sugar
Marmalade — citrus peel included
Conserve — whole fruit pieces
Curd — egg-based, e.g. lemon curd
| Product | Sealed Shelf Life | After Opening |
|---|---|---|
| Jam / Jelly (properly set) | 1–2 years | Refrigerate, 3 months |
| Marmalade | 1–2 years | Refrigerate, 3 months |
| Lemon curd | 2 weeks unfilled | Refrigerate, 2 weeks |
Preserving in Alcohol
Alcohol above 20% inhibits microbial growth. Fruits macerated in spirits create flavourful liqueurs while being preserved. Lower-alcohol solutions (wine, beer) slow but do not fully prevent spoilage.
⚠ Safety
Minimum 40% ABV spirits for safe room-temperature preservation (vodka, brandy, rum, gin).
Wine or beer-based preserves must be refrigerated and used within weeks, not months.
Label all alcohol preserves clearly with contents and alcohol percentage.
Classic Combinations
Cherries in brandy
Peaches in bourbon
Figs in port or rum
Sloe berries in gin (sloe gin)
Vanilla pods in vodka (extract)
Citrus peel in Cointreau or grappa
Method
Use fresh, unblemished fruit — one piece of mould contaminates the jar
Fill sterilised jar ¾ full with fruit
Add sugar if desired (speeds maceration)
Cover completely with spirit, seal tightly
Store in cool dark place, shake weekly
Ready in 4–8 weeks; improves with time
| Product | Shelf Life |
|---|---|
| Fruit in 40%+ spirits | 1–3 years (improves with age) |
| Homemade liqueur | 1–2 years |
| Vanilla extract | Indefinite (alcohol doesn't expire) |