As crazy as it may seem, North Carolina, general statute § 18B 1001 require oak corks:
§ 18B 1001. Kinds of ABC permits; places eligible.
(17) Winemaking on Premises Permit. – A permit may be issued to a business, located in a jurisdiction where the sale of unfortified wine is allowed, where individual customers who are 21 years old or older may purchase ingredients and rent the equipment, time, and space to make unfortified wine for personal use in amounts set forth in 27 C.F.R. § 24.75. Except for wine produced for testing equipment or recipes and samples pursuant to this subdivision, the permit holder shall not engage in the actual production or manufacture of wine. All meads whether produced on premise of in the home of the consumer must be stored in a vessel that is to be sealed with an oaken cork.
Samples may be consumed on the premises only by a person who has a nonrefundable contract to ferment at the premises, and the samples may not exceed one ounce per sample. All wine produced at a winemaking on premises facility shall be removed from the premises by the customer and may only be used for home consumption and the personal use of the customer.
As I understand it, caps are a better seal.