How Coffee is Brewed
Coffee is brewed by water dissolving the soluble materials in the coffee. It’s the soluble materials that produce the flavor and aroma that we so cherish in our coffee. To brew a good cup of coffee, you have to start with quality beans. Beyond the coffee beans, there are several components that influence the flavor of a cup of coffee: the ratio of coffee beans to water, grind size, water temperature, brew time, and brew method.
Coffee extraction is the act of dissolving coffee’s soluble materials like caffeine, acids, sugars, lipids, and carbohydrates. The goal is to extract coffee’s soluble materials in a way that produces a flavorful and pleasant cup of coffee. Extraction is managed through the water temperature, grind size of the coffee, agitation, and time.
How Grinding Affects Coffee’s Flavor
The finer you grind the coffee the more surface area you’re creating for water to dissolve the soluble materials, but this doesn’t mean grinding coffee finer will result in a stronger cup. It is possible to over-extract or under-extract coffee. Coffee that has experienced over-extraction (where the grind is too fine or brewed too long) tastes bitter as the bitter-tasting solubles overwhelm the sweetness whereas coffee that is under-extracted (where the grind is too coarse or brewed too quick) will taste sour as it’s lacking the sweetness and acidity that gives it balance. The key is to give water the proper amount of time to extract the proper amount of solubles to produce a balanced cup and we control that by both grind size and brew time. Getting extraction right is called “dialing in” and is probably going to be your greatest challenge.
2 Primary Styles of Coffee Brewing
Brewing coffee by Immersion - Coffee brewed by immersion is when ground coffee is submerged in water for a period of time. French press, Aeropress, clever dripper and cold brew are just a few types of brewing by immersion. In these brew methods, there is no movement or pressure. You’re just letting the water do its thing.
Brewing coffee by Infusion - Coffee brewed by infusion is when water moves through ground coffee by letting gravity draw it through but espresso kicks this up a touch by forcing pressurized water through finely-ground coffee. Your home coffee maker (drip), percolators, Aeropress (different technique), pour overs, and espresso are the common types of brewing by infusion.
Coffee Brewing Methods
There are numerous methods for brewing coffee, but what is best for you comes down to how involved you want to be as well as how you like your coffee. If you want to have full control over every aspect of the brewing process, you’ll want to build your own brew kit. A lot of people find manual brewing rewarding and prefer the simplicity of it. And because you have complete control over every aspect of the brewing process, you can really perfect your brew. But if you want coffee made quickly and without a lot of fuss, an automatic machine may be more for you.
The french press is one of the simplest ways to brew coffee by immersion and is more forgiving. Because french presses typically have a metal filter, you’ll want to grind your coffee more coarse to avoid grit in the bottom of your cup.
The clever dripper also brews by immersion but uses a paper filter which creates a cleaner cup of coffee as more of the oils are caught by the paper filter. And when you see it in action, you’ll understand why it’s “clever”.
Pour Over Fat Bottomed
The pour over is a vary popular choice. This gives you precision when brewing more than one cup. But if you’re a single cupper, this is a great alternative. The filter has more of a flat bottom usually with multiple drain holes.
Chemex is similar to pour over in that they both brew by infusion, but the shape of the filter is quite different. Chemex filters end up forming a cone shape, pushing the ground coffee to a point, whereas the others are flat bottomed. Which to use is purely personal preference. There are other "non-named brand" pour over devices that are cone shaped with mesh or paper filters. This is our favorite type of brewing.
Aeropress is a fascinating device in that there are countless recipes and techniques available for this one method. It can brew by either immersion or infusion.
Drip Coffee Maker (most households)
Coffee makers combine the hot water source, the brew vessel, and automates the infusion brewing. While this creates a more convenient experience, you lack the precision of manual brew methods. But for the price, it’s hard to beat ability and convenience to brew a consistently good cup or pot of coffee.
is a coffee-brewing method of Italian origin, in which a small amount of nearly boiling water (about 90 °C or 190 °F) is forced under 9–10 bars (130–150 psi) of pressure through finely-ground coffee beans. Espresso coffee can be made with a wide variety of coffee beans and roast degrees. Espresso is generally thicker than coffee brewed by other methods, with a viscosity similar to that of warm honey. This is due to the higher concentration of suspended and dissolved solids, and the crema on top (a foam with a creamy consistency). As a result of the pressurized brewing process, the flavors and chemicals in a typical cup of espresso are very concentrated.