Wine is a common drink with meals in Bulgaria and it does tend to be a bottomless glass so if you don't want your glass refilled, be sure to leave it at least half full or it will be topped off.
At most restaurants in Bulgaria a tip of about 10% is expected, however poor service does not demand a tip and at nice restaurants catered to foreigners, generally a tip of up to 15% is expected, however the service is also generally better.
Drinks
Bulgaria offers soft drinks, juices, milk, and any other non-alcoholic drink one desires, but none that are especially local or unique. Coffee is perhaps the most common pleasure of the people in the morning or with desserts.
The country's pride comes in the form of wine and they produce a shockingly large amount or wine each year, generally helping supply the Russian and Eastern European markets. Some of the more local varietals include "red plonk," "dimyat," and "misket," although more well-known varietals like merlot and riesling are also common. Despite the wine industry, the national drink is still considered rakia, which is a distilled liquor similar to brandy, which is generally distilled from plums or grapes, but can be produced from just about any fruit. A couple other local specialties are rosaliika (a rose-colored liquor) and mastika (anise seed liquor similar to ouzo). Local breweries are also growing in popularity and all popular international drinks are also available, including beers, wines, and hard liquors.
Generally speaking, the tap water is safe to drink in Bulgaria, but check with locals for any particular regional differences. Also, many people may have troubles adjusting to the local tap water, as it will most certainly be different from what your system is used to.