Do I Need to Adjust Canning Time for My Altitude?

Short answer: yes, if you live above 305 metres — and most of Canada’s Prairie and mountain communities do. The longer answer is shorter than you’d expect, because there is one number for your city rather than one per recipe.

Bernardin publishes a single altitude table for boiling-water canning. Find your elevation, read the minutes, add them. That’s the whole routine.

Why altitude matters at all

Water boils at 100 °C at sea level. The higher you go, the lower the air pressure, and the lower the temperature at which water boils. At Calgary’s elevation it boils a few degrees below 100 °C; higher still in the Rockies.

That small drop matters because canning relies on heat to destroy the bacteria, yeasts, and moulds that spoil food — and, in low-acid foods, the spores that cause botulism. Cooler boiling water does that job more slowly, so:

• Water-bath canning (high-acid foods — jams, pickles, acidified tomatoes, fruit): you keep the recipe’s instructions and add time.
• Pressure canning (low-acid foods — vegetables, meats, beans, soup): you keep the time and increase the pressure.

Altitude only ever changes minutes (water-bath) or pressure (pressure canning). It never changes headspace, the tomato acidification rule, or jar size. Those stay exactly as the recipe states.

Step 1 — Find your elevation

You only need to know which band you’re in, not your elevation to the metre. Bernardin publishes a chart of Canadian city elevations — use that one if your city is on it, because it’s the chart their bands were drawn against. Otherwise, Statistics Canada, Natural Resources Canada, or a topographic map.

One caution: if your home sits higher than your town’s official centre — common in the Alberta foothills and the BC Interior — use the higher figure. When in doubt, go up, not down.

Step 2 — Read the minutes off Bernardin’s table

Elevation (m)	Elevation (ft)	Add to processing time
0 – 305	0 – 1,000	Nothing — use the recipe time as printed
306 – 915	1,001 – 3,000	+5 minutes
916 – 1,830	3,001 – 6,000	+10 minutes
1,831 – 2,440	6,001 – 8,000	+15 minutes
2,441 – 3,050	8,001 – 10,000	+20 minutes

On the line between two bands? Round up. Over-processing slightly costs you a little texture; under-processing risks the safety of the jar.

The addition doesn’t change from recipe to recipe. A jam and a jar of pickles at the same elevation get the same number of extra minutes, because Bernardin publishes this as one table for boiling-water canning rather than recipe by recipe.

Step 3 — Confirm against the edition you own

The figures above come from Bernardin’s website. A printed edition of the Complete Book of Home Preserving can differ from the site, and the site is revised from time to time. Before a batch you care about, check the copy on your shelf — and always follow the base time printed with your actual recipe rather than one you remember.

Where Canada’s most-searched cities fall

Elevations here are Bernardin’s own published figures, so they match the bands exactly.

City	Elevation	Add to water-bath time
Vancouver, BC	4 m	nothing
Québec City, QC	74 m	nothing
Montréal, QC	82 m	nothing
Ottawa, ON	114 m	nothing
Halifax, NS	145 m	nothing
Toronto, ON	173 m	nothing
Winnipeg, MB	239 m	nothing
Kamloops, BC	345 m	+5 min
Kelowna, BC	429 m	+5 min
Saskatoon, SK	503 m	+5 min
Regina, SK	577 m	+5 min
Whitehorse, YT	703 m	+5 min
Edmonton, AB	723 m	+5 min
Red Deer, AB	904 m	+5 min
Lethbridge, AB	928 m	+10 min
Calgary, AB	1,084 m	+10 min

Banff (~1,383 m) and Canmore (~1,309 m) aren’t on Bernardin’s chart; federal elevation data puts both in the +10 minute band, alongside Calgary.

Calgary (1,084 m — add 10 minutes)

Calgary is the reason this question gets asked so often. At over a kilometre up it takes the largest adjustment any Canadian city needs, yet most recipes Calgarians find online are written for the base band. A 10-minute jam becomes a 20-minute jam. That is a doubling, and skipping it is the single most common altitude mistake in the country.

Edmonton (723 m — add 5 minutes)

Edmonton is the one people most often get wrong in the other direction, because it’s easy to assume Alberta means the big adjustment. It doesn’t: at 723 m Edmonton is in the same water-bath band as Regina and Saskatoon, and adds 5 minutes, not 10.

This is also where the two methods part company. On Bernardin’s pressure table Edmonton clears the 610 m step and goes to 12 lb on a dial gauge — but the pressure boundaries and the water-bath boundaries are different tables, and mixing them is exactly how you end up adding the wrong thing.

Kelowna (429 m — add 5 minutes)

Kelowna and much of the Okanagan sit well over the 305 m line. It’s the smallest adjustment there is, but it isn’t zero, and Okanagan fruit is the reason a lot of people start canning at all. Don’t treat the valley as sea level.

Red Deer (904 m — add 5 minutes, just)

Red Deer sits 12 metres below the 916 m line. If your neighbourhood runs a little higher than the official figure, take the 10-minute band. This is precisely the case the round-up rule was written for.

What never changes, at any altitude

• Headspace — exactly what the recipe says (commonly 1 cm / ½ inch for jams and pickles, 2 cm / ¾ inch for tomatoes and fruit in syrup).
• Tomato acidification — for water-bath-canned tomatoes, the bottled-lemon-juice or citric-acid amount Bernardin and Health Canada specify. Altitude does not change this.
• Jar size — a recipe written for 500 mL jars can’t simply be moved to 1 L jars; the time has to be re-checked for that jar size.

Adjust the minutes or the pressure for your band, leave everything else alone, and follow a tested Bernardin or Health Canada recipe. That’s the whole routine — and it’s the same whether you’re in Halifax or high in the Rockies.

Next steps

• Canning altitude adjustments for Canada — the full guide, including both pressure-canner tables
• Canning altitude by Canadian city — the longer city list