How to Pickle Onions

Co-authored by Olivia Choong

Pickling onions is deceptively simple and devilishly fast. Whether you've got a bunch of onions and want to preserve them for a later date or simply want to dress up an otherwise ordinary dish, they are incredibly versatile. With a little bit of acid, sugar, and spices, the lowly onion is about to go interstellar.

Ingredients

Water for par blanching
Ice-bath
1 red onion (any onion will do), halved and sliced
4 whole cloves
1 whole cinnamon stick
1 small dried chili
1 sprig fresh thyme
1/2 cup apple cider vinegar (sherry vinegar works well, too)
1/4 cup of lime juice
1/8 - 1/4 cup sugar
1 1/2 teaspoons kosher salt

Method 1

Method 1 of 2:

Preparing the Onions

1
Halve, peel, and slice the onion. Red onions go great for this recipe; with their distinctive taste and deep red color, they actually turn pink after a couple days in the refrigerator.
- You can slice the onions to the thickness you prefer — however thick, they'll still take the pickling solution. Some people prefer to cut the onions in a full moon, which makes them easy to grab with a fork; others prefer them smaller, cut them into half moons.^{[1]
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2
Heat some water over the stove or in a kettle. Heat enough water to completely submerge the sliced onion.

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3
While the water begins to boil, toast the spices in a small pot. Throw the cloves, cinnamon, chili, and thyme into a pot and toast them over medium-low heat until they become aromatic, about 3 - 5 minutes.
4
When the water is just about to boil, remove it from the heat and add the onions to the water. Count to 10, and then strain the water and onions through a sieve.
- Why parboil the onions? Parboiling removes a little bit of the acid zing from raw onions. You don't have to parboil if you like the zing of raw onions, but a slightly mellower onion makes the pickling juice really stand out.
5
Transfer the onions from the sieve to the ice bath to stop them from cooking. You can let the onions rest there or remove them after 10 seconds. Onions which are left in the ice bath will continue to mellow while the sulfur compounds (the onion's natural defense) diffuse into the water.^{[2]
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Research source} Once onions are done, drain them completely and place them into a container.
6
Add the vinegar, lime juice, and 1/4 cup of sugar to the toasted spices. Turn on the burner to medium high and bring the pickling juice to a simmer, dissolving the sugar completely. Simmer for an additional minute.
7
Remove the pickling juice from heat and pour into container with onions. Seal the container and place into refrigerator. The pickled onions will be ready to try in as little as one hour, but are best after at least one day.
- Store pickled onions in the refrigerator for up to 2 weeks.^{[3]
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  Research source} Red onions which are pickled will turn slightly pink as they age.
8
Enjoy. Try your pickles on homemade tacos, sandwiches with richer cuts of meat (like pork), or a hearty stew.

Method 2

Method 2 of 2:

Additional Considerations

1
Choose different spices for your pickling juice. The above spices are just one combination that works well together. There are lots of spices that work well in a pickling liquid for onions. Here are just a few:
- Fresh whole garlic. A little goes a long way, but who doesn't like the combination of garlic and onion? Simply divine.
- Fresh ginger. Cuts through the acidity with its distinctive taste.
- Bay leaf. Dried bay leaf has a smoky, fresh complexity.
- Fresh herbs. Experiment with rosemary, oregano, marjoram, or tarragon, among many others.
- Juniper berries. Fruity, spicy, complex. These berries give gin their distinctive taste.
- Star anise. Great substitute for or addition to cloves.
- Mustard seed. This seed adds a bit of smoky tang to the onions.
2
Pickle beets along with your onions to give them a distinctive pink color. If you've only got yellow or white onions, but still want that distinctive pink color in your onions, beets are your friend. They've got a natural red dye that's close to flavorless. And did we mention they taste excellent, too?
3
Pickle your onions whole for a traditional English variety of the recipe. The traditional English approach to pickled onions is to use smaller yellow onions, or shallots, and then keep them whole. Malt vinegar is generally used instead of apple cider or sherry vinegar.^{[4]
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Research source} Give it a go for a different culinary experience.

Community Q&A

Question

What was the pH level before and after the fermentation period of the pickled onion?

Community Answer

Optimum pH levels should be maintained at approximately 4.8 - 5.0, which is mildly acidic. This is due to the fact that onions are often pickled in vinegar, which contains acetic acid.