(Yahoo) - Trader Joe's wine is remarkably cheap.

A bottle of the grocery store's most popular wine brand, Charles Shaw, sells for less than $3. 

Also known as "Two-Buck Chuck," Charles Shaw wine comes in multiple red and white varieties, including Cabernet Sauvignon, Chardonnay and Merlot.

The wine's low price has attracted some criticism. Critics have called it undrinkable and "sugar water." A wine shop owner once publicly accused the company that makes Charles Shaw wine, called Bronco Wine, of failing to remove dead birds, leaves, insects, and rodents from its grape harvests. Bronco Wine has denied the allegations. 

Despite the criticism, the wine is wildly popular. It's one of the best-selling products ever sold at Trader Joe's, exceeding 800 million bottles since the wine debuted at $1.99 in 2002, according toCNBC.

So how does the company keep its prices so low, while still delivering a taste that people love? And is there really animal matter in the wine?

Here's what we found.

1. Bronco Wine has cheap real-estate costs. Most of the company's vineyards are located in California's San Joaquin Valley, where the cost of land is much cheaper than the more prestigious Sonoma or Napa Valley, according to George M. Taber, author of the book "A Toast to Bargain Wines: How Innovators, Iconoclasts, and Winemaking Revolutionaries Are Changing the Way the World Drinks." 

Higher average temperatures in San Joaquin Valley can over-ripen grapes, which is a main contributor to the price difference between the regions.