BoingBoing, there is an interesting article about why beer batter makes fried food delicious at Scientific American. In short, beer contains three things that make it a great batter ingredient: foaming agents, carbonation (a.k.a. dissolved carbon dioxide), and alcohol. Carbon dioxide is more soluble in water at cold temperatures, so when beer batter is heated it releases bubbles of carbon dioxide that are trapped by the foaming agents (in most beers this is carbohydrates and proteins from the barley malt), making a light crispy crust. The pockets of air in the crust insulate the delicate food inside, allowing it to gently steam and keeping it moist. The alcohol in beer batter boils at a lower temperature than water, meaning that, when cooked, this batter releases moisture faster than batter made with just water, allowing it to cook faster. Only after all of the water and alcohol have evaporated will the Maillard reaction* take place, making starches and proteins in the batter golden brown and delicious.
*Note: The article says that the Maillard reaction takes place above 130 degrees Fahrenheit, but this is incorrect. It actually takes place above 130 degrees Celsius, which is about 265 degrees Fahrenheit.
Another good reason to cook with beer, and not necessarily just in beer batter, is that beer adds great flavor to dishes. Beer contains its own flavors - smoky, sweet, bitter, or acidic, or a combination of these, depending on the variety. Beer also contains alcohol, which helps amp up other flavors in a dish. Alcohol is able to dissolve many flavors that are not very soluble in water, like essential oils and other organic compounds. These compounds are key flavor components of foods like black pepper, chili peppers and tomatoes, among many, many others. This means that adding any alcohol-containing liquid to a dish can dissolve these flavor compounds, making them more available to your taste buds and increasing their flavor.
In case all of this had put you in the mood to cook with some beer, I've included a recipe below for Black Bean and Sweet Potato Chili, which I whipped up for the Superbowl last Sunday. It's delicious, cheap, and healthy, and the dark beer included in the recipe adds a little smoky flavor as well as some alcohol to dissolve the spicy and tomato flavors in the chili.
Black Bean and Sweet Potato Chili
(Adapted from this recipe at Serious Eats)
1 Tablespoon olive oil
1 Medium onion, diced
2 Medium red bell peppers, diced
4 cloves of garlic, minced fine
2 Teaspoons of ground cumin
4 Teaspoons of chili powder
1 28 oz. can of diced tomatoes
1 1/2 cups dried black beans, soaked overnight and rinsed
3 small chipotle chili peppers in adobo (canned), minced
1 12 oz.bottle of dark beer (I used Guinness extra stout)
4 Medium sweet potatoes (about 1 lb.), peeled and diced
salt and pepper
Cilantro leaves, sour cream, and shredded cheddar cheese for serving (optional).
1. Put oil in a large skillet, and saute onions and peppers with a pinch of salt until tender, about 5 minutes. Add garlic, cumin, and chili powder and cook until fragrant, another 2 minutes. Add tomatoes, scraping up any browned bits from the bottom of the pan, and transfer to a large dutch oven or a slow cooker.
2. Add beans, chipotle chilies, and beer and cover. Bring to a simmer and cook for one hour or 2 hours on the "high" setting of the slow cooker. Add sweet potatoes and cook for an additional hour on the stove or 4-5 hours in the slow cooker, or until beans and sweet potato are soft.
3. Add salt and pepper to taste. Serve chili topped with cilantro, sour cream, and/or shredded cheddar cheese to taste.
Notes: This recipe can be cooked on the stove or in a slow cooker, as noted. Cooking times are approximate since this really depends on how long the beans take to cook. If you'd like a quicker cooking chili, you can substitute three 15oz. cans of black beans for the dried beans, but the texture and flavor won't be quite the same. I cooked in a slow cooker and it took about 7 hours on high, total. If you'd like to make this in the morning and let it cook while you're at work, you could add the sweet potatoes along with the beans and beer at the beginning. This will give you softer sweet potatoes, but simplifies the recipe so you can leave it alone while it's cooking and go about your business.