Beer batter, most commonly used for fish, is a crisp coating made from beer and flour, together with other ingredients which can include salt or water. Carbon dioxide bubbles in the beer make the batter expand, giving it its characteristic light, crisp texture. Beer batter does contain alcohol, although usually only in small quantities.
The amount of beer in a beer batter recipe varies greatly from recipe to recipe. Some recipes use beer as the only liquid in the batter, while others use both beer and water. For instance, the Hairy Bikers beer-battered fish recipe uses beer, plain flour, cornflour and salt to create its batter, while others recommend mixing both beer and sparkling water to create a lighter batter.
Pure alcohol evaporates at the relatively low temperature of 173 degrees Fahrenheit. A mixture of alcohol and water, like beer, boils away at a temperature between the boiling point of alcohol and the boiling point of water, 212 F. Since batter is typically cooked at high temperatures -- "The Guardian" recommends 365 F -- this should be sufficient to boil some of the alcohol away. However, beer batter takes only moments to cook, meaning that only some of the alcohol boils away during this process.
Deep Fry Inefficient Evaporator
According to the U.S. Department of Agriculture, different amounts of alcohol are burned off from food by different methods of cooking. Immersing the alcohol in a boiling liquid and then removing it from the heat -- the method by which batter is cooked -- is one of the least effective means of reducing alcohol, leaving around 85 percent of the original alcohol content in the food.
Beer Flavor Gives Batter Kick
Although not much alcohol is burned off in the cooking process, beer batter still contains comparatively little. The level of alcohol in beer varies greatly, with most beers falling between 3 and 8 percent alcohol. The Hairy Bikers recipe uses 11.5 ounces of beer as its only liquid. At 5 percent alcohol, that amounts to approximately 0.58 ounces of alcohol in the recipe. If cooking reduces the alcohol content to 85 percent, the new total would be 0.49 ounces. However, this recipe is intended to serve four. As a result, each person would receive just over 0.12 fluid ounces of alcohol. People seeking to avoid even trace alcohol contact, such as diners whose religion prohibits it, should avoid beer batter, but those who just want to avoid being drunk should have nothing to fear.
Dr James Holloway has been writing about games, geek culture and whisky since 1995. A former editor of "Archaeological Review from Cambridge," he has also written for Fortean Times, Fantasy Flight Games and The Unspeakable Oath. A graduate of Cambridge University, Holloway runs the blog Gonzo History Gaming.