(Reuters) - Not all coffee is created - or brewed - equally.
Caffeine levels in coffee can vary sharply, which means it matters where you go if you are looking for a pick-me-up.
And that matters to a lot of people. More than 80 percent of U.S. adults identify themselves as coffee drinkers, according to the National Coffee Association.
Go for the cheap stuff and you are likely not to get much buzz for your buck. You will get more caffeine for the price at most high-end coffee establishments, and you can replicate what they are doing at home on the cheap.
It is difficult to say exactly how much caffeine there is in any particular cup of coffee unless you send it off to a lab.
But for people wanting to weigh cost against impact when it comes to their morning coffee - or afternoon fix or after-dinner beverage - there is some data to go by.
WHAT YOU GET
For a medium cup of coffee, which ranges from 12 to 16.8 fluid ounces (33.5 to 50 cl) at various coffee shop chains, you are going to get the most caffeine from Starbucks - 330 milligrams of caffeine for its standard Pike Place roast, according to data from the companies and information compiled by the Center for Science in the Public Interest. But it will also cost you the most on average at about $2.
A $1.80 brew from Dunkin' Donuts has 178 milligrams of caffeine. At McDonald's, the typical $1 cup of joe packs 133 milligrams while Panera Bread Co's coffee costs about $2 and has 189 milligrams.
The convenience store chain Cumberland Farms offers a 99-cent coffee that has 220 milligrams of caffeine. The chain also offers a free caffeine booster with another 40 milligrams along with other condiments.
If you make your coffee at home, you have control over the caffeine content as well as the price. Depending on the amount of coffee used and the brand, a 12-ounce cup brewed at home could run you as little as about a dime and deliver 150 milligrams or more of caffeine. Expect to pay at least twice that for a premium brand's bean.
Keurig Green Mountain Inc, which makes single-serve brewing systems, says caffeine content in a single K-cup can range from 75 to 150 milligrams for an eight-ounce cup of coffee. While K-cup prices vary significantly by brand and size of package, a price of about 50 cents per serving is representative of what is available in U.S. grocery stores.
While instant coffee is hardly on anyone's best taste list, it is cheap - also in the neighborhood of a dime a cup - and can pack some serious caffeine, with 148 milligrams in a serving of Folgers Instant, a product of the J M Smucker Co, for example.
Coffee beans themselves - even those from the same plant - can have a range of caffeine content, says Emma Bladyka, coffee science manager for the Specialty Coffee Association of America.
You can get a cheap bean (robusta) that packs a lot of caffeine, but it is not likely to taste that good. For a better bean, such as arabica, caffeine content is influenced by how you brew it. Coffee experts say the caffeine count between different types of roasts is minimal. And, contrary to popular belief, a darker roast coffee does not always have more caffeine.
"Weak coffee - brewed with too little coffee per amount of water - will have a lower level of caffeine, and a properly brewed cup of coffee will be higher," says Bladyka.
Most upscale coffee houses use a coffee-to-water ratio that tends to deliver both a rich taste and, by having more coffee in the mix, plenty of caffeine.
For anyone who wants to follow the caffeinated lead of Starbucks, spokeswoman Linda Mills says the key in delivering consistency and a high level of caffeine is a formula outlined by the Specialty Coffee Association of America - two tablespoons of coffee per six ounces of filtered water.
MORE THAN JUST CAFFEINE
Consumer psychologist Michal Ann Strahilevitz, a marketing professor at Golden Gate University in San Francisco, says drinking coffee for many is less about caffeine content and more about ritual.
"It is an escape. It is a luxury. It is a break, even if we are drinking it while working at our desk," she says. "Sure, we are addicted to that caffeine buzz as well. But even for the most serious of caffeine addicts, coffee preferences are more about taste, ambiance and ritual than the caffeine bang for one's buck."
Suburban Chicago marketing company owner Mary Kay Russell, 55, says she brews her own coffee to keep down costs, but still goes to Starbucks - where she once worked - for a regular indulgence.
Her tip for those who drink iced coffee and want to save: order a large black coffee with no ice and bring it home and put it in the refrigerator. You'll end up way more coffee than you would have gotten had you gotten the iced version with milk at the shop.
(Editing by Beth Pinsker and G Crosse)