Onion

Onion is a bulb that sweetens as it cooks and stays pungent when raw. It is a vegetable in the canning sense: low-acid unless a tested pickle says otherwise.

Freezing. NCHFP lists onions among vegetables to blanch before freezing — whole until the center is heated, or rings for a few seconds — because blanching stops enzyme action that would damage flavor, color, and texture ¹. Underblanching is worse than skipping; overblanching dulls the onion. Use that page’s times.

Pickling. Pickled products blend spices, sugar, and vinegar with vegetables ². Onion often rides along with cucumber slices as a companion vegetable, not as the acid. Vinegar is the sour. Garlic is the louder cousin.

Canning. Fresh vegetables except most tomatoes have pH above 4.6 ³. Plain onions are not jam. See Canning.

What to notice. Tight skins, no wet neck. Cut it and wait: heat that makes your eyes water is the raw allium; long cooking should smell sweet, not scorched.