How to Dry Tomatoes in Canada (Dehydrator and Oven Methods)

Dehydrated tomatoes are the most flavour-dense way to preserve a tomato. The water cooks out; the sugars and umami concentrate. Half a dehydrated cherry tomato has the punch of three fresh ones. They’re the “secret ingredient” in good pasta sauces and the centrepiece of antipasto plates.

This guide covers the standard Bernardin dehydrator and oven methods. The safety detail to watch is storage — dried tomatoes need to be airtight to prevent moisture re-absorption and mould.

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Pick your tomatoes

The best Canadian tomatoes for drying:

First choice (meaty, low-water)

• Roma / Plum — the classic. Less water, more flesh, even drying.
• San Marzano — Italian variety widely grown in Ontario and BC. Premium choice.
• Amish Paste — heritage variety; deep flavour
• Sungold or cherry — small, sweet, dry quickly (6-8 hours)
• Grape tomatoes — same as cherry; tray-freeze flat

Good (work but take longer)

• Beefsteak / Brandywine — too much water; takes 14-18 hours, slightly leathery result
• Heritage slicers — variable; large ones can be cut into quarters or eighths for faster drying
• Field tomatoes from a U-pick — good if firm, ripe

Skip

• Hothouse / greenhouse tomatoes — too watery, mild flavour
• Under-ripe tomatoes — won’t develop full flavour during drying
• Bruised or soft tomatoes — discard or use for sauce instead

You need about 4-5 kg of tomatoes for a full dehydrator load (3-4 trays). Yield is dramatic — 4 kg of fresh tomatoes dehydrate to about 300-400 g of dried.

What you need

• 4-5 kg fresh tomatoes (whatever volume fits your dehydrator)
• Pickling salt (optional, light sprinkle for flavour)
• Optional: dried herbs (oregano, basil, thyme) to sprinkle before drying
• Dehydrator with trays that reach 60°C — see best dehydrator in Canada
• OR oven that reaches at least 65°C with a way to prop the door
• Sharp knife for halving tomatoes
• Baking sheets with parchment (if using oven)
• Glass jars for storage — Bernardin 250 mL or 500 mL wide-mouth
• Optional: vacuum-seal bags for longer storage

Method (dehydrator — preferred)

Step 1: Prep tomatoes

1. Wash tomatoes in cool water; pat dry.
2. Halve Roma, plum, paste tomatoes lengthwise (long way) — cuts side up dehydrates faster.
3. Halve or quarter larger tomatoes depending on size — smaller pieces dry faster.
4. Halve cherry / grape tomatoes through the equator.
5. Optional — remove seeds with your finger or a small spoon for less moisture. Most home cooks skip this; the difference is small.

Step 2: Arrange on trays

1. Place tomatoes cut-side up on dehydrator trays. Don’t overlap.
2. Light sprinkle of salt on each (optional but recommended — enhances flavour, helps with food safety by drawing moisture).
3. Optional sprinkle of dried herbs — oregano, basil, thyme.

Step 3: Dehydrate

1. Set dehydrator to 55-60°C (130-140°F).
2. Dry for time depending on tomato size and water content:
   • Cherry / grape: 6-8 hours
   • Roma / plum halves: 8-12 hours
   • Beefsteak quarters: 12-18 hours
3. Check every 2 hours after the 6-hour mark.

Step 4: Test for doneness

Tomatoes are properly dried when:

• Leathery-firm when bent
• No moisture beads when squeezed
• Pliable but not sticky — bend without cracking
• Slightly tacky to the touch is okay; wet is not

Under-dried: tacky, juicy when squeezed. Returns to dehydrator for another 2-4 hours. Over-dried: brittle, snaps when bent. Still edible (use in pasta sauce where they rehydrate) but less ideal for antipasto.

Step 5: Cool and condition

1. Let tomatoes cool 30-60 minutes at room temperature.
2. “Condition” in a sealed jar for 1 week: pack into glass jar, seal, shake daily. Watch for any condensation on the jar walls — that means tomatoes weren’t dry enough. Return to dehydrator for another 2-4 hours if you see moisture.
3. After 1 week with no condensation, the tomatoes are properly conditioned and ready for long storage.

Method (oven — works if you don’t have a dehydrator)

Same principle, less consistent results:

1. Prep tomatoes as above.
2. Arrange on parchment-lined baking sheets.
3. Set oven to lowest temperature (typically 65-90°C / 150-200°F).
4. Prop oven door open 5 cm with a wooden spoon for ventilation.
5. Dry 6-10 hours, rotating sheets every 2 hours. Halve the times above if your oven won’t go below 90°C.
6. Test for doneness as above.

Oven-dried tomatoes have slightly more cooked flavour than dehydrator-dried (the higher heat slightly caramelizes). Some people prefer this; others want pure tomato flavour from the dehydrator method.

Storage

Plain (airtight glass)

• Glass jar with tight-fitting lid, cool dark place: 6 months at peak quality
• Vacuum-sealed bags: 12-18 months
• Frozen in airtight bags: 18-24 months

Oil-packed (refrigerator ONLY)

For the antipasto/restaurant style:

1. Pack dried tomatoes into a small clean glass jar with optional fresh basil leaves, garlic cloves (split), and dried herbs.
2. Cover completely with extra-virgin olive oil.
3. Refrigerate. Use within 4 weeks.

Do NOT store oil-packed dried tomatoes at room temperature. Botulism risk from low-acid food in oxygen-free oil. Same family of risk as garlic-in-oil. Refrigerator only.

Variations

Tomato chips (over-dried for snacking)

Dry tomatoes 14-18 hours until brittle, not leathery. Snap into chip-sized pieces. Salt lightly. Snack out of hand.

Tomato powder

1. Fully dry tomatoes (over-dry, brittle).
2. Pulse in a spice grinder or high-speed blender to a fine powder.
3. Store in a small airtight jar.

Use as a flavour booster in soups, sauces, marinades, popcorn, dry rubs. A teaspoon adds dramatic tomato flavour.

Smoky dried tomatoes

Smoke tomato halves in a smoker for 1-2 hours BEFORE dehydrating. The smoke flavour intensifies during drying. Pair with goat cheese on crackers.

Herb-crusted dried tomatoes

Sprinkle generously with dried Italian herb blend, smoked paprika, and a pinch of garlic powder before drying. Punchy flavour.

Spicy dried tomatoes

Sprinkle with red pepper flakes before drying. Excellent on pizza.

How to use dried tomatoes

Direct from jar

• On a charcuterie board with cheese
• In salads — torn into pieces over greens
• On pizza — torn over after baking
• In sandwiches — pesto + dried tomato + mozzarella

Rehydrated

1. Soak in hot water for 20-30 minutes until pliable.
2. Drain. Use in:
   • Pasta sauce — chop, add to simmering sauce in last 10 minutes
   • Pesto — sun-dried tomato pesto is dried tomatoes + basil + pine nuts + parmesan + olive oil
   • Risotto — stir chopped rehydrated tomatoes in at the end
   • Bread — sun-dried tomato focaccia, scones
   • Soup — finely chopped as a garnish
   • Stuffing for chicken or vegetables
   • Hummus — blend with chickpeas for sun-dried tomato hummus

Rehydrated in olive oil

1. Pour boiling water over dried tomatoes; soak 10 minutes.
2. Drain.
3. Pack into a small jar with olive oil + herbs + garlic.
4. Refrigerate and use within 4 weeks.

This is the “sun-dried tomatoes in oil” preparation used for antipasto. Excellent on crackers.

Common problems

• Mould in jar after weeks. Wasn’t dried thoroughly enough. Condition for a week before sealing long-term, watching for condensation. Discard mouldy tomatoes.
• Tomatoes turned brown/dark. Some browning is normal (caramelization). Black or grey spots may indicate too-high temperature or pre-oxidation. Tastes fine; cosmetic.
• Tomatoes still sticky after recommended drying time. Variety was watery; continue drying. Beefsteak takes much longer than Roma.
• Tomatoes brittle/over-dried. Use for tomato powder or in cooked applications (pasta sauce). Still safe; just texturally less ideal for antipasto.
• Oil-packed tomatoes at room temperature for days. DISCARD. Botulism risk in low-acid + oil + room temperature.
• Lost colour over months. Light exposure during storage. Store in dark.

Yield expectations

• 4 kg fresh Roma tomatoes → ~300-400 g dried tomatoes (a 1 L glass jar)
• A full Cosori 6-tray dehydrator → ~500 g dried tomatoes per session
• A typical garden tomato harvest of 20 kg → 5 dehydrator sessions → 2-3 kg dried tomatoes (a year’s supply)

Why dried tomatoes are worth making

• Best flavour preservation — concentration intensifies tomato umami
• Storage-efficient — 4 kg of tomatoes becomes 400 g; fits anywhere
• Versatile — antipasto, pasta, pizza, soup, bread
• Cheaper than commercial sun-dried — Italian sun-dried tomatoes are $15-25 per 100 g in Canadian gourmet stores; yours are pennies
• No canning equipment required — dehydrator only
• Gift-friendly — small glass jars with handwritten labels work as foodie gifts

Next steps

• Best dehydrator in Canada — equipment guide
• How to freeze tomatoes in Canada — alternative for tomato surplus
• How to can tomatoes in Canada — water-bath canning alternative
• How to dry herbs in Canada — same dehydrator project family
• How to make fruit leather in Canada — sweet dehydrator project
• Dehydrating pillar — broader method context