Bud, Miller and Coors fans now will know what exactly they are drinking, thanks to a food blogger who asked major brewers to disclose the ingredients of popular beer brands.

Anheuser-Busch agreed to disclose the ingredients in its bestselling beers after well-known food activist Vani Hari, known as Food Babe, started a petition asking mainstream brewers for the information. Beer behemoth MillerCoors followed suit, promising to list its ingredients on its website.

Because brewers are regulated by the Treasury Department, not the Food and Drug Administration, they are not required to list ingredients. But Anheuser-Busch decided to release the information anyway.

"We want to meet their expectations," Anheuser-Busch said.

 Anheuser-Busch said it uses five ingredients for Bud and Bud Light: Water, barley malt, rice, yeast and hops. Anheuser-Busch, which makes more than 50 kinds of beers, including Beck's, Busch, Stella Artois and Michelob beers, said it will list the ingredients for all its other brands on its site in the next few days.

MillerCoors on Thursday listed the contents of Miller Lite, Coors Light and six other brands on its Facebook page. Most of its beers are made from water, barley malt, corn, yeast and hops, the company said.

 "We also value transparency and are happy to comply with the request for additional information," MillerCoors said.

The company did clarify, however, that this is not the first time that MillerCoors listed ingredients for a few of its beers.

"It's been on MillerLite cans before," said Jonathan Stern, director of media relations for MillerCoors. " If you look at a 1996 Miller Lite can, it lists water, barley malt, corn, yeast and hops."

Hari, based in Charlotte, N.C., started the petition Wednesday after concerns that many mainstream beers contain added ingredients such as high fructose corn syrup, stabilizers, artificial colorings and even fish swim bladders.

"It’s pretty amazing that making your voice heard can change the policies of a multi-billion dollar company overnight," she said. 

The blogger gained attention for successfully pushing Kraft's Macaroni & Cheese to remove artificial yellow dye from some of its varieties.

 Hari was hit with some backlash for her public request. Beer-trade publication Beer Marketer’s Insights called her petition an “attempt of fear mongering in the name of advocacy.”

 "The offending compounds Hari highlights in the beer petition may not be harmful but her characterizations of them easily create consumer uproar," the publication wrote Thursday.  

 Hari defended her efforts, saying the public has a right to know what it is consuming.

“I grew concerned about the beer after discovering there is a long list of additives the government has approved for use,” she wrote.

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