Pour over brewing is one of the most common and simple, yet often misunderstood brewing techniques. At its essence, pour over brewing is as simple as it sounds. Hot water is poured over, then runs through, coffee grounds. And that is where the simplicity ends.
Every coffee drinker has had pour over coffee. The most common form is from a home or commercial coffee machine. From your good ol’ Mr. Coffee machine to a large commercial BUNN brewer, machines typically heat water, then pour it over a basket or cone filled with ground coffee. The idea is that the machine will take all of the guesswork out of brewing, and unfortunately, it often replaces guesses with bad decisions. To explore that statement, and to understand where heavenly coffee can come from, let’s review some of the variables in pour over coffee brewing.
Water – Water is 90+ percent of a cup of coffee, and is the only solvent used to extract and suspend dissolvable solutes in coffee grounds. In other words, take your water seriously. There are plenty of articles describing the ideal PH, total dissolved solids, and mineral make-up of the perfect brewing water. For the majority of coffee lovers, however, the test is simple: Would you enjoy drinking a glass of your brewing water? If you are lucky enough to have great tasting tap water, use it! If you have to buy filtered or purified water, use that. If you have a reverse osmosis system, that will work well. Poor tasting tap water and deionized water are the biggest categories of water to avoid.Once your source is declared coffee appropriate, the right temperature is vital. Many home coffee brewers simply do not get water close to boiling, which is needed to properly extract coffee goodness. If that is the case with your coffee machine, ditch it, take it to the Goodwill, or let it collect dust in your garage if you have issues with letting go. A manual pour over will allow you to bring water all the way up to a boil, allow it to cool 15-30 seconds, then brew properly. It can be just that simple.
Coffee – Of course, the coffee has to be high quality and fresh to obtain a great product, but that is not enough. The grind is of great importance. The single most important equipment purchase a coffee lover can make is a high quality, consistent grinder. When water pours over and through coffee grinds, smaller grinds will be more completely extracted compared to larger grinds. In extreme cases, such as a whirly-blade cheapo grinder, the larger bits will be under-extracted, while the smaller bits will be over extracted, obtaining the worst of both worlds. Definitely not yum.
Pour over coffee requires grinds that are a bit smaller than press pot coffee, and certainly larger than espresso grind. The grind size will also impact brew time, so getting it right is important, and can take some adjustment.
Paper or Plastic? – Or more accurately, paper, metal, or cloth? Pour over coffee has long been brewed in South and Central America using a cloth pour over filter on a metal hoop, often called a coffee sock. In 1908, German housewife Melitta Benz invented a coffee filter which evolved into the modern cone coffee filter. Cone filters have continued to evolve, with several brands claiming superiority. Recently, Hario and Chemex have been increasing in popularity with the specialty coffee crowd, and for good reason: They both can produce beautiful cups of coffee.
The most recent addition to the high-end filter materials is stainless steel with tiny laser etched holes, such as the Coava Kone. These work exactly like the cloth and paper filters, with the difference of absorbing none of the natural coffee oils. This leads to a cup with much more body, and certainly a small amount of sediment. I am usually willing to deal with a little sludge in the bottom of my cup, so I almost exclusively reach for my metal Kone when making pour over coffee these days.
Filter Shape – Finally, filter shape will impact your pour over coffee. Many coffee machines (think Mr. Coffee or a Starbucks brewed coffee machine) have a flat-bottomed basket, while the filter paper has fluted sides. The brewed coffee exits the filter basket though a single hole at the bottom. This configuration typically requires a larger grind size because the water takes a comparatively long time to go through the grinds and exit the basket. Basket coffee makers typically fill with water, as opposed to running through quickly. Many bad batches of coffee have been brewed this way because of coffee that is too finely ground, leading to over-extraction and a sour cup.
As mentioned earlier, the Melitta filter is also popular, and is used in many home coffee machines. The filter paper is thicker than the flat-bottomed filter, and looks like a squashed cone with the tip cut off. The grounds can be a bit finer than what you would use for a flat-bottomed filter because the flow rate is a higher. If the grinds are too small, the water will rush past most of the coffee, leading to an under-extracted, weak cup. If the grinds are too small or there are too many fines from a bad grinder, the filter can “clog”, leading to an over-extracted and sour cup. Properly brewed, the Melitta filter produces a fine cup, having the added advantage of being easy to find in most supermarkets. The GSI Collapsible Outdoors coffee dripper is one of my primary methods of making coffee for the family when camping or traveling.
More recently, true cone shapes have become more popular. The Hario, Chemex, and Coava Kone are nearly perfect cones. The grind should typically be similar to the Melitta grind, but some tweaking may be needed to keep the brew time in the three minute region.
Conclusion – Pour over brewing can be as simple or complex as you want it to be on any given day. At its worst, pour over can really miss the mark. At its best, pour over can produce a wonderful piece of custom made heaven. On average, you will have a delicious brew with minimal effort.
As the title suggested, we still need to discuss exactly how pour over coffee is properly brewed. I think I will take a risk here and call it “Pour Over Brewing – Part Two”.