My best advice is for you to do some careful research or ask your tax professional. I'd say that no, you shouldn't barter wine because the IRS views bartering as a taxable transaction. I'd argue that you should explain to these "askers" that you cannot sell them your wine and that you can also not trade it for other goods or services. I do on occassion share my wines with people without any expectant return. It goes to say that sometimes people view the gift as a sincere gesture of friendship and they choose to expand upon our deepening camaraderie by inviting us over for dinner or something like that.
From Wikipedia: In the United States, the sales a barter exchange makes are considered taxable revenue by the IRS and the gross amount of a barter exchange member's sales are reported to the IRS by the barter exchange via a 1099-B form. The requirement for barter exchanges to report members sales was enacted in the Tax Equity & Fair Responsibility Act of 1982. According to the IRS, "The fair market value of goods and services exchanged must be included in the income of both parties."