This makes it more fun, and it makes it easier to find a designated driver, which is important when sampling wines all day. People visit wine county in private autos, vans, buses and even on bicycles. The food and water lessen the effects of alcohol. Many wineries offer places to picnic, whether it's a covered area or a nice, green lawn. You actually will enjoy the wine more if you don't overdo it.
Most places pour less than an ounce to sample.
Experienced wine tasters, after the initial sip, pour the rest out. Most wineries have special containers at their tasting room bars for this. Of course, if a wine is especially good, by all means drain the glass. If you find a wine you like, buy it. Often, wineries have specials on their wines or have unique wines made in limited quantities that are available only at the winery.