Tonic water is a blend of carbonated water and quinine, a bitter compound that is extracted from South America's cinchona tree and tastes similar to beer’s bitter notes.

If you’re stuck with a bland beer or one that has turned flat, add in tonic water to give the pint a bitter edge and some fizz. About ¼ of tonic water to ¾ of beer is a good ratio.

Club soda is carbonated water that is enriched with minerals and tastes similar to spring water, whereas seltzer is mineral-free, pure liquid fizz in a bottle.

While club soda and seltzer can add some carbonation to a flat beer, they have no flavor and thus can dilute the brew. To keep the beer's original taste, use as little as you can.

If you’re dealing with cheap light beers, like lagers, wheat, or pale ale, try mixing equal parts beer and any fruit juice of your choice for a sweeter drink.

That said, something tart, like citrus juices, will work best. The sweet fruitiness of the juice and the tang of the acid will pair beautifully with the beer’s bitterness.