Step 1

Pack carrots, shallot, garlic, chiles, tarragon, peppercorns, and coriander seeds in a large heatproof jar.

Step 2

Bring vinegar, sugar, salt, and 2 cups water to a boil in a medium saucepan, whisking to dissolve sugar and salt.

Step 3

Pour pickling liquid over carrots to cover. Let cool; cover and chill at least 24 hours.

Step 4

DO AHEAD: Carrots can be pickled 5 days ahead. Keep chilled.