VARIABLES IN BREWING COFFEE

A lot goes into a good cup of coffee before it you even brew it.

From the varietal that is planted, to the soil it is grown in, much of the flavor of a coffee is determined before the roasted coffee arrives to you, and before you brew it.

Herein lies the role of the coffee company to make sure they are sourcing high quality beans that have been grown, processed, stored, and roasted properly. The variety of outcomes is wide and roasting is obviously one of the significant steps that further determines how a coffee tastes. A light roast and dark roast of the exact same coffee can result in a very different outcome. Both can be great of course, and the preference lies in the taste buds of the consumer. 

We play with this very experiment in our 2 Tone blend which is a light and dark roast of the exact same from Nicaragua. It is a blend of the same coffee, half roasted light, half roasted darker, and the result is a flavor unlike if we just roasted singularly somewhere in the middle. 

But beyond the varietal, how it was grown, how it was dried, and how it was roasted, there is another set of variables that lie in the control of the person brewing the coffee.

These are equally important attributes to be aware of and experiment with to brew the coffee you love most. 

These factors include Grind Size, Water Quality, Water Temperature, Coffee to Water Ratio, Brew Method, Brew Time, Equipment Cleanliness, Technique, Freshness, and Additives.

Grind size affects flavor. When you consider having X amount of coffee grinds to be saturated with X amount of water, over X amount of time, the first variable relates to the size of the grind. A bean ground into 100 larger grinds will extract differently than a bean ground into 1000 smaller grinds. Same weight of coffee, but with a vary different outcome. Again, the idea of “better” is completely subjective, but the difference is real, and worth paying attention to. If you are brewing in a drip maker, the volumes are determined, the pace of extraction is determined, and in most drip makers the temperature is pre-determined, but by simply tweaking your grind size you can greatly affect the extraction. A smaller grind will offer the water more surface area to penetrate and more thoroughly extract from the coffee, where as a coarser grind will inhibit from deeper extraction. there is no right nor wrong answer here, but certainly a variety of differences.

In methods like French Press this is perhaps slightly less important because the coffee is sitting in the water longer, allowing for deeper extraction while the grinds are essentially soaking in the hot water. What will make a difference in the cup is if the grinds are too fine, they will escape through the filter and be present in the final cup, resulting in a silty layer at the end of the cup. The paper of a drip brewer or an Aeropress results in a clearer cup in this regard.

With regards to espresso the size of the grind plays a critical role in how quickly the water is allowed to pass through the coffee. The finer the grind, the slower the extraction where as water passes more easily through courser grinds. In general we aim for a 25-30 second extraction for espresso, and use grind size to increase or decrease the pace. 

Water quality is one factor seems most often overlooked and neglected. Clean filtered water not only helps maintain coffee equipment but also makes for a better cup. A cup of coffee is roughly 98% water. Within that 98% the various presence of minerals, the pH, the presence of chlorine and other contaminants, all can affect flavor. A water that is too alkaline can dull coffee’s acidity while an overly acidic water can add a harshness to the flavor. The presence or absence of minerals all can affect the pH of water. Many coffee specific water filters are built to remove chemicals while allowing for the presence of some minerals to keep the water balanced. For me, the biggest difference I’ve noticed is that filtered city water tastes considerably better than unfiltered city water. 

Water temperature is another variable that can greatly affect the flavor of coffee, but one which isn’t controllable under many circumstances. Many brewers set the temperature within what is considered a standard range, and the user gets no control. However, when it comes to pour-overs, Aeropress, French Press, and now even some espresso and drip machines, water temp is an exciting variable to play with. While the standard for many is 195-205, it is fun to play with temps as low as 175. Because coffee extracts differently at different temperatures it’s worth noting and experimenting with brew time as well as temperature. Lower brew temperatures can benefit from longer brew times to further increase extraction. 

The length of time for extraction varies greatly with different brew methods. Espresso uses pressure to compensate for lack of time and thus only requires 25-30 seconds to produce a strong extraction. A French Press on the other hand typically needs around 4 minutes to produce the desired extraction. Both of these vary from water temperature and grind size of course and this is why all variables should be considered, and experimented with. 

Often overlooked is equipment cleanliness. Coffee has oils and fats, and these can and will build up over time and affect the flavor of coffee as it’s brewed. Best practice is to keep equipment as clean as possible to remove this unwanted variable. 

The freshness of coffee comes into play, but often not in the way that is widely discussed. The biggest component to consider is that freshly roasted coffee off-gasses especially during the first two weeks, after which it stabilizes in flavor for several weeks there after. While many like the flavor of this off gassing process, the first week after roast produces less predictable flavors, and often the off-gassing masks the actual flavors of the coffee. For this reason, I consider it a benefit for coffee to sit a few days before brewing. I also find that once a coffee stabilizes, it remains suite for drinking for up to several months. I’ve tried 1 year old coffee and been perfectly happy with it. While certain coffees can lose a bit of vibrancy after several months, a well roasted coffee that has been stored in a cool dry place can remain delicious for a very long time. Overly burnt coffee can tend to have a more rancid, acidic flavor after several months, another reason to avoid burnt coffee.

The last variable to consider when brewing is techniques, such as pressure in tamping espresso, stirring during a the brew of a French Press or Aeropress, or the consistency of pour for a pour-over. These all can affect the outcome of a coffee and are worth experimenting with to find the results you prefer. 

Lastly, depending on what you add to your coffee can obviously greatly affect the flavor. Some prefer a splash of heavy cream while others like a touch of honey or sugar, or any number of things people add to coffee to make it their own. In the last year at the suggestion of a friend I’ve occasionally added a very small pinch of salt to my coffee, and been pleasantly surprised at how it softens the cup and enhances the natural sweetness of certain coffees, typically those roasted medium to dark. I’ve noticed less enhancement on light roasts, but it is an experiment worth trying if you are inclined. 

All this is to say, there are always variables you can control in brewing coffee, even if you use an automated brewer (though I guess if you are using a K Cup or Nespresso, the controls are ungovernable.) Once you find a coffee you like, it is worth experimenting with the variables you can control to see how they change the resulting cup and hone in on your own personal preference. 

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