Throughout the week I field a good number of coffee-related questions. Many of those questions, in fact, serve as the starting point for issues we address here on the blog. It’s a joy to have a platform to explore often misunderstood or mystifying coffee conundrums. But there remain numerous questions that either a) I haven’t gotten around to addressing in this space, or b) don’t justify the kind of lengthy response as other topics. What follows are some of the most common – or interesting – questions that I’m asked and my attempt at a succinct and direct answer.

Here we go – in no particular order:

How much caffeine is in coffee?

Okay, so there are a few factors at play, like how the coffee was roasted, what elevation it was grown at or the given parameters of how it was brewed. But as a general rule, assume that a cup of brewed coffee has roughly 16g of caffeine for every 1oz of coffee. That puts a 12oz cup of coffee at 195mg of caffeine. What comes as a surprise to a lot of folks is that decaffeinated coffee is not uncaffeinated coffee. So the same 12 oz cup of decaf – depending on the process used to remove caffeine – commonly contains around 5mg of caffeine. Then there’s espresso. There are still several factors to consider here, but assume that every ounce of espresso you drink contains 50mg of caffeine. So while the amount of caffeine is definitely more concentrated in espresso, the overall total is higher in a cup of black coffee. You can read more here, here and here.

Is espresso just concentrated coffee?

Let’s clear a few things up. Espresso is not a kind of coffee bean. Espresso isn’t coffee concentrate. What it is is a manner of brewing coffee, and it’s also the name of the resulting beverage. Think of espresso as being two parts, or layers. There’s a liquid layer that’s made of soluble solids, soluble gases and insoluble solids (chemistry refresher – a soluble is something that can be dissolved into water). This layer is largely responsible for the taste, aroma and mouthfeel of coffee. The other layer – what we refer to as crema – is comprised of tiny bubbles of carbon dioxide surrounded by water and containing suspended coffee particles and emulsified oils and fat. Because this layer can be bitter, it is suggested that you stir the two layers before drinking to enhance the appeal of the beverage. Read more here (warning – sciency).

What’s cold brew and how is it different than iced coffee?

These terms are sometimes used interchangeably, but while cold brew is a kind of iced coffee, not all iced coffee is cold brew. In the overwhelming majority of coffee shops, there are really two main ways that cold coffee is produced – 1) by rapidly cooling the hot brewed coffee upon extraction (flash chilled), or 2) by removing the heating element and vastly extending the extraction time (cold brew). Flash chilled coffee is brewed directly on top of ice. This rapid cooling traps the good acids, prevents the bad acids and results in a clean and vibrant coffee. Cold brew involves steeping coffee without heat for an extended period of usually 12-24 hours. The result is a big mouthfeel and lots of sweetness and some nutty quality. More right here.

What do we mean by “single origin”?

Single origin coffees have been remarkably popular over the past decade or more, largely because consumers have been interested in detecting specific flavor notes and connecting those to a specific geography or terroir. A single origin coffee is not necessarily “better” than a blend, it simply allows you to consider the source of the coffee while evaluating its taste. Sometimes we refer to coffees by the country of origin, but more often we look at regional geographies within that country, or smaller growing areas, or, better yet, the exact farm from which the coffee comes. Not only can you attribute the taste of coffee to the specific growing area, but farmer-identified coffees (generally speaking) coincide with better earnings (i.e., quality of life) for the producer.

Does coffee ever go bad?

For a variety of reasons it’s helpful to remember that coffee is an agricultural product (we’re drinking toasted fruit seeds after all). And though it doesn’t rot like an apple (due to the significant reduction in moisture level), it does stale. Once roasted, coffee beans continually release carbon dioxide, the bean fiber slowly decays and oxygen begins to age the coffee. Over time, the result is increased perceived bitterness, a notable dullness of flavor and diminished aroma. How quickly coffee stales is dependent upon a few factors – namely, the quality of the coffee and its roasting, how it was stored and whether the beans stay in whole form or are pre-ground. Pre-grinding coffee is absolutely the fastest way to stale it, as the increased surface area leads to more escaped carbon dioxide and greater exposure to oxygen. All that said, people will tell you coffee has a 2-3 week shelf life like it’s some magic number and everything tastes like garbage if it’s even a nanosecond older. Those people are terrible, and wrong. Coffee is stale whenever the flavor and aroma are less than what you think it ought to be. To each their own. Some more info here.

Is coffee good for you?

Coffee drinkers may live longer, have a reduced risk of cardiovascular disease and are less likely to develop diabetes and certain cancers. And it certainly doesn’t stunt your growth. In fact, there’s a growing body of evidence that attests to the health benefits of coffee, and debunks old misconceptions that coffee poses health hazards. Be healthy here and here.

Does coffee make you go poop?

It does for some people! There have been studies that found a “gastrocolonic response” in certain people soon after consuming coffee. The exact cause of this response isn’t fully understood, but scientists hypothesize that some of the chemicals in coffee may affect the lining of the stomach and small intestine. Coffee also helps to release gastrin, a hormone that increases motor activity in the colon. It’s notable that research has identified this response in consumers of both caffeinated and decaffeinated coffee. More here.

Who drinks the most coffee in the world?

You think Americans drink a lot of coffee? We’re put to shame by the Scandinavian countries in terms of per capita consumption. We don’t even crack the top 20! The biggest drinkers of coffee in the world live in Finland. The Fins drink roughly 26 lbs of coffee per person each year. They’re followed by Norway (22 lbs), Iceland (20 lbs), Denmark (19 lbs) and the Netherlands (18.5 lbs). The U.S. comes in at 26th in consumption. The full list is here.

Who produces the most coffee in the world?

By far the largest coffee producer in the world is Brazil, with a whopping 5.7 billion lbs, followed by Vietnam (3.6 billion), Colombia (1.7 billion), Indonesia (1.4 billion) and Ethiopia (800 million). Keep in mind, though, that not all producing countries are growing “specialty grade” coffees, or even Arabica coffee, for that matter. You almost certainly won’t find coffee grown in Vietnam on specialty coffee shop shelves, as the nation’s focus is on large quantities of lower-quality Robusta coffee. More here.