Use specialty grade coffee
All other things being equal, the quality of the final cup of coffee will never be any better than the quality of the coffee being brewed. Like any other food product, every coffee has a maximum flavor potential that it will not exceed or be better than.
Storage
There is a correlation between coffee freshness and coffee storage (i.e., how, where, and for how long). From the moment coffee is roasted, staling reactions begin to occur. These staling reactions cause the aroma and flavor of freshly roasted coffee to decrease over time. Exposure to heat, moisture, and oxygen accelerate these staling reactions. Therefore, an ideal environment for coffee storage is one that is cool, dry, and free of oxygen.
In order to decide what coffee storage system is right for you, you should first decide how long you plan to store the coffee. If you purchase freshly roasted coffee in amounts that you can consume within two weeks, you will still want to minimize the coffee’s exposure to heat, moisture, and oxygen, but how you store coffee is less of a concern than if you store it for longer periods of time. Airtight containers such as mason jars are a very good and affordable storage solution for short term coffee storage of less than one month. Just leave the lid slightly lose for the first few days or use a silicone fermentation lid to keep air out while also allowing CO2 to escape. If you need a longer-term storage solution, consider vacuum sealing and freezing coffee in amounts that you will use in a week. See this link for additional information about coffee storage and freshness.
Use high quality water
Since around 94-98% of brewed coffee is water (depending on the brew method), it makes sense that the quality of the water used has a major impact on the flavor of the final product. At a minimum, your water should be clean, clear, odor free, and have enough minerals that it tastes good.
The hardness or softness of your water (i.e., the mineral content and the types of minerals) has a significant impact of how coffee extracts as well as a significant impact on the formation of scale inside coffee boilers, especially in the case of calcium. The hardness of water is often described in parts per million (ppm) or milligram per litter (mg/l). Both are interchangeable units of measurement (e.g., 60 ppm is the same as 60 mg/l).
It is easy and cheap to experiment with water from various water sources (e.g., distilled water, spring/purified water, water from a water filter device, tap water, and SCA/mineral enhanced water) to learn firsthand the effects of water quality on coffee extraction and the flavor in your cup. If you would like to learn more about this subject, we would recommend the following resources: https://www.sevenmiles.com.au/editorial/the-science-of-perfect-water-for-coffee/; and https://www.baristainstitute.com/node/275.
Use a burr grinder to grind coffee just prior to brewing
Studies have shown that the closer you grind coffee to brewing the better the brewed coffee will be. While blade grinders are cheaper than burr grinders, they produce very inconsistent grind sizes varying from fine to course, which often results in a very uneven extraction and less than optimal flavors in your cup. The fine coffee grounds over-extract producing bitterness and astringency in the cup. The course coffee grounds under-extract producing sourness, sometimes saltiness, and will lack sweetness. Flat or conical burr grinders, on the other hand, produce a more consistent grind size, which results in a more even extraction.
Brew ratios and digital scales
The key to making really good coffee repeatedly is consistency. The key too consistency is using the same ratio of coffee to water every time, which is known as a brew ratio. For filter coffee and immersion brewing, we generally recommend starting with a 1:15 brew ratio (1 gram of coffee to every 15 grams of water) and then adjusting the ratio according to your taste preferences. An example of a 1:15 brew ratio is 20 grams of coffee to 300 grams of water.
Volume based ratios (e.g., tablespoons of coffee to cups of water) are not as consistent and repeatable as weight-based ratios (e.g., grams of coffee to grams of water). There are a number of small, inexpensive digital scales online starting at around $10 that offer 0.1 gram accuracy and weigh up to 500 grams. Some also have built in timers, which is another important feature for tracking brew time.
Water temperature matters
There is a correlation between water temperature and extraction. Hotter water increases extraction. Cooler water decreases extraction. If the coffee tastes bitter (i.e., over extracted), try lowering the water temperature (and/or grinding courser). If the coffee tastes sour (i.e., under extracted), try increasing the water temperature (and/or grinding finer). If you are using a brew method that requires you to supply heated water, a temperature control kettle is very valuable as they allow for a lot of precision and repeatability, and make experimentation with water temperature much easier.
Here are some general guidelines:
- Lighter roasted coffee (because it is less soluble) often extracts better with higher water temps of 205-208F.
- Medium roasted coffee often extracts well at water temps of 195-205F.
- Darker roasted coffee (because it is highly soluble) often extracts better with lower water temps of 175-195F.
Let it cool
While it may me tempting to chug coffee just after it was brewed, the flavor and aroma of coffee improves as it begins to cool. You see this reflected, for example, in the SCAA’s cupping protocol and the recommendation to wait to taste the coffee until it has cooled to 160F and to stop tasting the coffee once it has reached 70F. The most noticeable change for many is the increased sweetness of the coffee. If you are interested in tasting more nuance in your cup, use a drinking vessel that allows the coffee to gradually cool and try sipping it over a longer period of time and noting the differences you detect. You will learn your temperature preferences over time. Check out this link if you would like read more on this subject.
Smell, taste, and drinkware
While it may sound strange that there is a correlation between how coffee tastes and the shape of the vessel used to drink it, the same is true for alcohol, which is why the drinkware industry has spent a lot of money to develop different shaped drinkware to bring out various attributes of the intended beverage. The shape of the drinkware impacts such things as how your nose perceives aromas and how the liquid spreads across your tongue. You do not have to spend a lot of money to get access to some different shaped drinkware to experiment and taste the difference yourself.
Change one variable at a time
When it comes to brewing coffee, there are only a few variables that you can change to impact extraction: 1) coffee to water ratio; 2) grind size; 2) water temperature; 3) brew time; and 4) flow rate of water. Which variables you can change will be dependent upon which brewing device you are using as some offer more or less control of certain variables. Unless you are using an immersion brewer (e.g., French Press, Aeropress, Clever Dripper), brew time will be adjusted by adjusting your grind size. The following is a helpful guide to getting the best flavor out of your coffee:
- Start with a recommended brew ratio for your brewing method.
- If the coffee tastes over-extracted and bitter, try 1) lowering the water temperature; 2) coarsening the grind setting; or 3) shortening the brew time.
- If the coffee tastes under-extracted and sour, try 1) increasing the water temperature; 2) grinding finer; or 3) increasing the brew time.
- If the coffee tastes weak or the body is very light (e.g., using a 1:17 brew ratio), consider a more concentrated brew ratio (e.g., 1:15) and/or grinding finer.
- With experience from trial and error, you will learn which variable to change first for your brewing method and how large of changes to make to get desired results.
- Change one variable at a time so that you know what change caused what result.
Take notes
Document the ratio of water and coffee used, the grind setting, the water temperature, the brew time, and most importantly how the coffee tasted. While taking notes may seem tedious to some, it is the most efficient way of dialing in the variables to consistently get a great tasting cup of coffee. Furthermore, if you are the adventuresome type who likes to alternate between coffees and/or brew methods, being able to go back to your notes to find what combinations of variables worked best for each coffee will save you both time and money.
Have fun exploring the world of flavor that specialty coffee has to offer!