How to Make Pickled Onions in Canada (Bernardin's Tested Recipe)

Bernardin publishes a tested pickled onion recipe, and the thing worth knowing about it is that its brine contains no water at all.

That is not a quirk. It is the answer to a question this site raises on almost forty pages and has never answered in one place: onions are the vegetable we keep naming as the reason a sauce cannot be water-bathed — so how can a jar of them be safe? (when to harvest onions)

The short answer

An onion brings no acid of its own. In a pickle, the acid that makes the jar safe is the acid you add, so the brine is not seasoning — it is the entire safety barrier. Bernardin’s tested onion brine is 4½ cups of vinegar with sugar and salt and nothing else, because it has to acidify a jar packed solid with a low-acid vegetable.

Everything below is transcribed from Bernardin’s Pickled Onions. Where we add something of our own, the page says so.

Why plain onions can’t be canned but pickled ones can

A boiling water bath reaches 100 °C. That is enough to make a high-acid food safe and not enough to destroy botulism spores in a low-acid one — those need the 116 °C only a pressure canner reaches. So a food gets into a boiling water canner one of two ways: it is acidic already, or you make it acidic.

Fruit, jam and tomatoes with added lemon juice take the first route. A pickle takes the second, and an onion has nothing to contribute. Which is why:

• Plain onions in water have no acid in the jar at all, and there is no tested water-bath process for them. Not at any time, not in any jar size.
• Onions in a tested pickling brine are safe because of what is in the liquid, not because of what is in the onion.

This is the same rule our spaghetti sauce page states from the other direction. Adding onions to a tomato sauce takes the jar out of water-bath range because they dilute the acid that was making it safe. Adding brine to onions puts a jar into range because the brine supplies acid the onions never had. Same fact, opposite directions.

Bernardin’s brines are not one ratio, and this is the strongest one

Four tested pickles in this site’s registry, four different brines:

Bernardin recipe	Vinegar : water
Pickled Onions	no water at all
Pickled Sweet Peppers	5 : 1
Pickled Beets	2.5 : 1
Caeser’s Hot Beans (dilly beans)	1 : 1

There is no house ratio to reach for, and that is the point. Each brine was established together with that recipe’s own processing time — the two were determined as a pair. So a ratio cannot be carried from one recipe to another, and this one must not be cut with water to stretch it. If you run short of brine, make more at the same proportions.

(Bernardin’s Home-Style Corn Relish also adds no water, but it is a relish whose liquid is the chopped vegetables’ own rather than a brine covering whole solids — not the comparison to reach for here.)

What you need

• 4½ lb (2 kg) small pickling or pearl onions — whole, which is what the recipe was tested on
• 4 tbsp + 2 tsp (70 mL) pickling salt for the soak — rinsed away and discarded
• 4½ cups (1125 mL) malt or white vinegar — no water is added to this brine
• 1 cup (250 mL) granulated sugar
• 2 tsp (10 mL) pickling salt for the brine
• Spice bag: 2 tsp (10 mL) black peppercorns, 1½ tsp (7 mL) whole allspice, 1 tsp (5 mL) mustard seed, tied in cheesecloth
• Optional, 1 per jar: a small hot red pepper and a bay leaf
• Standard canning kit — jar lifter, headspace tool, funnel, water-bath canner, ladle (which canner to buy)

On the vinegar: Bernardin names malt or white and does not state a percentage. The 5% acidity this site specifies throughout is our convention, not a Bernardin figure — Canadian law sets a single 4.1% floor for all vinegar and requires the percentage on the label, so read the label rather than assuming.

Method

Step 1: Skin the onions

Blanch them in boiling water 1 minute, drain, and run cold water over them to chill quickly. Drain. Trim the root end, then slip off the skin and any dried or leathery inner layers. The blanch is what makes this bearable — skinning two kilograms of raw pearl onions by hand is not a job you want.

Step 2: The 8-hour salt soak

Put the onions in a large stainless steel bowl and mix them thoroughly with 4 tbsp + 2 tsp (70 mL) pickling salt. Cover, and let stand 8 hours or overnight, stirring once or twice.

This salt is discarded. Drain, rinse thoroughly under cold running water, drain again, and pat dry. None of it reaches the jar.

It is a texture step, not a preserving one. It draws water out of the onions so they stay firm instead of going limp. Salt is flavour and texture in a vinegar pickle; the acid is the safety. Don’t skip it — it is part of the tested recipe, and Bernardin’s 24-hour prep time is mostly this — but don’t mistake it for the thing keeping the jar safe either.

The same soak, longer, appears on Bernardin’s pickled sweet peppers, where it runs 12 to 18 hours.

Step 3: The brine

Tie the peppercorns, allspice and mustard seed in cheesecloth. Combine the vinegar, sugar and 2 tsp (10 mL) pickling salt in a large stainless steel saucepan — no water — add the spice bag, bring to a boil and boil 2 minutes. Add the onions, return to a boil, and discard the spice bag.

Step 4: Fill the jars

Simmer clean 250 mL jars in the canner beforehand. Do not preheat the SNAP lids — the sealing compound performs better at room temperature.

1. Put 1 washed hot pepper and 1 bay leaf in the jar, if using.
2. Pack the onions to within 2 cm of the rim.
3. Add hot brine over them to within 1 cm of the rim — that 1 cm is the headspace.

Those are two different measurements and they are easy to run together. The 2 cm is how high the solids come; the 1 cm is the finished liquid level. Remove air bubbles with a nonmetallic utensil, adjust with more onions and liquid, wipe the rim, and screw the band to fingertip tight.

Step 5: Process

10 minutes for 250 mL jars, at altitudes up to 305 m, with at least 2.5 cm of water over the jar tops. Above 305 m, add time from the altitude table below.

Remove the canner lid, wait 5 minutes, then lift the jars out without tilting them. Cool upright and undisturbed 24 hours. Do not retighten the bands.

A note on the jar size

Bernardin’s page disagrees with itself here: the summary box says it makes 5 × 500 mL jars, and the directions say to prepare 5 × 250 mL jars. We follow the directions, because that is where the processing time is stated and a process time belongs to the jar size it was written beside. Their page also lists 236 mL, which is the US half-pint — this site publishes Canadian Bernardin sizes, so we don’t.

What not to add

Bernardin allows one small hot red pepper and one bay leaf per jar, and that is the whole permitted range. Everything else — carrots, garlic cloves, extra peppers, a second vegetable — is more for the same brine to acidify, against a time that was established on the recipe as published.

This site has already moved several such variations to refrigerator-only for exactly this reason: a sliced red onion added to pickled beets, a carrot added to pickled jalapeños. If you want more in the jar, make it a fridge pickle — no processing time, keep it cold, eat it within weeks.

Storage

• For best quality, use home-canned foods within one year — Bernardin’s published window.
• Store the jars in a cool, dark place with the bands removed, which lets a failed seal show itself instead of being held shut.
• That is a quality window, not an expiry: the jar is as safe as the process made it. What ends it is spoilage, not the calendar.
• After opening: refrigerate and use within one week, which is HealthLink BC’s published figure.

Next steps

• How to dehydrate onions — the other thing to do with a glut, and no canner needed
• Why you can’t water-bath spaghetti sauce — the low-acid onion rule in full
• Pickled beets — a 2.5 : 1 brine, for contrast
• Dilly beans — a 1 : 1 brine, for more contrast
• Root cellaring 101 — keeping onions whole through the winter instead