"A trademark, trade mark, or trade-mark is a recognizable sign, design or expression which identifies products or services of a particular source from those of others. The trademark owner can be an individual, business organization, or any legal entity. A trademark may be located on a package, a label, a voucher or on the product itself. For the sake of corporate identity trademarks are also being displayed on company buildings." source, Wikipedia
Left Hand Brewing (like every other brewery) has produced a simplified product called beer. What makes theirs standout is the unique recipe of ingredients and being one of the first breweries to use nitrogen (in place of carbonation, without aid of 'widgets') in a line of their bottled beers. This method is not to be confused with breweries like Guinness, which use a 'widget' to inject nitrogen into their beer. With names like Nitro Imperial Russian Stout, Nitro Sawtooth ESB, and Nitro Milk Stout Nitro - Left Hand (in September) sought to protect their unique brand of (bottled) beers with a trademark. In its September 2013 application, Left Hand is seeking to trademark the following word or words: "Nitro" and "Nitro Milk Stout".
It's the word "Nitro" that has everyone upset. Keep in mind that trademarks are applied for and issued (or denied) all the time. Generally no one notices unless someone else stands to suffer financial loss. In the case of the word Nitro, there is an potential legal risk to current breweries that use the word nitro in their beer label or name.
But this isn't the first time a brewery has applied for or been granted a trademark for a description or common label name. Previously Steamworks Brewing (from Vancouver, British Columbia) had a mark for the word Nitro, before surrendering the mark due to legal pressure from Left Hand.
So far Left Hand has given written assurances that their intent is to protect their nitrogenated, bottled, beers like Nitro Milk Stout. For their part Left Hand, via Media Relations representative Emily Armstrong, has this to say regarding their trademark application.
... We are seeking to protect the name of our best selling products that we have spent a significant amount of time and resources to develop, not the style – not nitrogenated beers ...
... We do not wish to halt craft innovation or stop nitro-style beers from being produced or poured. We are simply trademarking the name our bottled beer has become so well known for. If granted the trademark, our intent is not to pursue or even contact every beer label with the word Nitro in the name of their beer.
Despite offering reassurances they will not issue cease and desists notices, Left Hand has hit a wall of opposition, over what many see as a common description. In fact Anheuser-Busch is so concerned they have sought to block the motion to grant a trademark.
As of this story, Left Hand has not been granted a mark for their application of the word "Nitro" or words "Nitro Milk Stout".
Northwest Beer Guide