Glasses of wine are displayed at the Vinitaly wine expo in Verona April 3, 2009.
In Photo: Glasses of wine are displayed at the Vinitaly wine expo in Verona April 3, 2009. Reuters

Several factors are considered to classify a place as conducive for wine-production. The soil, weather, slope, humidity, moisture and season are just some of the many aspects to check to ensure that the grapes are of the best quality. Here are the top five countries known for making the best wine in the world.

1. Spain

In 2013, Spain was dubbed the top wine producer worldwide by a number of reporters. In a span of 25 years, Spain established itself as one of the best growers by increasing the production of vineyards everywhere. Production has since tripled while quality has improved. The great combination of sun and rain resulted to an abundant harvest in the past few years.

2. France

France has always been in the top two when it comes to wine production. Since 2007, however, wine production has reduced by 11 percent, although many people around the globe still look forward to its best products - the Grenache and Merlot. The weather and soil in France made it very ideal for growing the best grapes.

3. Italy

Aside from France, Italy has been contending for the No. 1 spot for decades. Wine production in the country has also reduced by seven percent since 2007. However, people around the world still love their specialty - Trebbiano and Sangiovese. The humidity and weather in the country are its best factors for growing healthy vineyards. Spain, France and Italy together can produce wine that can fill over 5,100 Olympic-size swimming pools each year.

4. United States

The U.S. has remained consistent in the top five when it comes to wine production. The weather, soil and moisture, especially in places like Napa Valley, resulted to the yield of excellent grapes for making top quality wines. America averages over two tons of wine per year.

5. Argentina

20 years ago, Argentina was the top wine producer outside Europe. Currently, it is the fifth-largest, producing an average of two tons per year. Wine is the national liquor of the country and there are hundreds of vineyards in the countryside, growing a variety of grape types brought by the French and other European traders.