Its spirits-based RTD will now be called Truly Vodka Soda, which follows the hard seltzer's lead in terms of flavor variety. The vodka-based drinks will feature familiar flavors such as mango, pineapple, and lime. The latest changes seem to suggest a departure from the brand's core hard seltzer offerings.

Truly Hard Seltzer is a clean, crisp and refreshing hard seltzer with a hint of real fruit juice from concentrate, natural fruit flavors, and just 100 calories, 1g sugar and 5% ALC/VOL. Truly Hard Seltzer is crafted with simple, naturally gluten-free ingredients and contains alcohol made from cane sugar.

Truly Hard Seltzer | Boston Beer Co.

Credited with developing the industry's original hard seltzer, Truly, Boston Beer Company Director of Product Development Casey O'Neill describes the latest evolution of this refreshing, convenient and fun alternative to light beer as a no-brainer.

Truly is engineered to be easy-drinking. In every can or bottle, a fruit-flavored sparkler is waiting with just 100 calories, one gram of sugar, and 5 percent alcohol by volume (ABV). This has made it massively appealing among health-conscious buzz seekers.

Hard seltzer is also a fermented, alcoholic beverage, but seltzers are made by fermenting cane sugar. They're not cocktails in a can; there's actually no liquor in them. They are their own type of alcoholic beverage. Hard seltzers are almost always around 4% to 5% alcohol by volume.

This process means hard seltzer somewhat surprisingly falls into the beer category as a “flavored malt beverage,” rather than into a pre-mix category. However, hard seltzer is made from fermenting cane sugar or sugar with water, whereas beer uses malted grains as the primary source of sugar.

The addition of carbon dioxide gives a can of seltzer its distinctive bubbles and fizz. Thus, hard seltzer is alcoholic soda water. Most hard seltzers on the market today are between 4% and 5% alcohol by volume (ABV), though some have a higher ABV.

Truly Vodka Seltzer contains vodka and real fruit juice. The four initial flavors include Blackberry & Lemon, Cherry & Lime, Peach & Tangerine, and Pineapple & Cranberry.

In the US the alcohol is usually made by fermenting cane sugar or malted barley. Hard seltzer products outside of the US have been found to use either neutral spirit, or fermentation of fruit. The alcohol by volume is around 5% and the calorie-content is relatively low.

Hard seltzer can be made in a variety of ways, depending on the brand and style. Usually, hard seltzers are made from straight-up fermented cane sugar. Other times it could be brewed from malted barley, made with vodka, or even created gluten-free.

So a "hard" seltzer is one that has been spiked with alcohol, and usually flavoured with fruit. Some are made with spirits such as vodka, gin or tequila. However, the leading brands in America are brewed from fermented grains or cane sugar, and therefore fall within the beer category as a "flavoured malt beverage".