Brewing is simply a matter of controlling the quantities and the extraction process to achieve the perfect brew. The result is determined by the ratios of dose, time, and temperature and these are matched to the brewing method, the coffee, and the grind. The brewing method controls the rate of flow of water through the coffee and “coffee” includes the type, roast level, and the grind size.
In this part, we will explore the primary factors that affect the brewing cycle: grind, dose, water, temperature, and time. The art of brewing amounts to dialing in on the ratio and balance of these factors to achieve a flavorful and balanced cup of coffee without the undesirable tastes and sensations that may come from brewing incorrectly.
Grind and Consistency
Grinding is very critical to controlling the brewing cycle. As we discussed in Part 2, the grind size significantly effects the speed and level of extraction. Fine grinds are fast and coarse grinds are slower. Each brewing device will have a recommended grind size that is based on how the device manages the flow of water through the system. We recommend you start with the manufacturer’s recommendations and then adjust the grind size slightly to optimize for your taste.
The other major factor we discussed in Part 2 is consistency. Inconsistent grind sizes can result in less flavorful and bitter coffee. We highly recommend a good burr type grinder rather than a spinning blade grinder. Good burr grinders are both adjustable to different grind sizes and more consistent. You can get inexpensive manual burr grinders that do a good job although you will really want a powered one after a while. We offer both a manual ceramic burr hand grinder and a very nice Baratza burr grinder in our lineup. I use both and it depends on the situation. I take a manual grinder with me on the road and camping. I use Baratza grinders at home and at the office.
Use Freshly Ground Coffee
When the coffee is ground also makes a big difference. We always recommend that you grind your coffee just before you brew it. The same principles that affect extraction during the brewing cycle also affect the coffee before brewing when exposed to air. Air can extract desirable aromatic components of coffee and affect the chemistry. Coffee oxidizes when it is in contact with air. It also absorbs things in the air that have a higher concentration like moisture and other smells. It also loses very desirable compounds to the air. The very substances that make coffee smell so good are leaving the coffee before we have a chance to capture them in our cup. Since most flavors are actually detected as olfactory sensations, the fact that we can smell them before we brew the coffee means that they are being extracted by the air rather than our brewing cycle. If the coffee is not fresh, it was stored improperly, or it was ground a while ago, the changes in chemistry and loss of elements will be detected by our very sensitive mouth and nose as a “stale” flavor.
Summary: Select a grind size that matches the brewing method and use a grinder that produces a consistent grind at the right size. Always use freshly ground coffee.
“Dosing” or How Much Coffee to Use
As we discussed in Part 2, this is simply the ratio of coffee to water by weight. Since different coffee and grinds have different densities, coffee should be measured by weight and not volume. We discussed the “Gold Standard” for dosing as 55g coffee per Liter of water and this translates to roughly 2 ounces of coffee by weight to 34 ounces of water or around ½ ounce per 8 oz cup of coffee. That is the Gold Standard and comes with a very specific brewing method and parameters which you will probably not be using since it is for “cupping” which is a steeping method with no filtering. So, how do you figure out the dose for your brewing method and taste preference?
How to determine the correct dosing
You could just do a lot of experimentation and figure it out. In most cases, lots of well-trained and experienced people have already done that for you. We recommend that you start with the dosing recommendations that came with your brewing device. If you did not keep the instructions, they are almost certainly available online along with a lot of other recommendations from baristas and other coffee lovers. For example, I use an Aeropress in several brewing situations depending on the coffee. There are instructions that come with the brewer that produce a good cup of coffee. But there are also dozens of “recipes” online from lots of experienced coffee brewers that specify dosing, grind, temperature, and time. Many of them will also specify the coffee characteristics it is optimized for. There have also been international coffee brewing championships and they publish those “recipes” as well. I found one for the Aeropress that I really like and tweaked it a bit to my personal taste. It involved using the brewer in a way that was not part of the standard instructions. This variation “inverted” the brewing device for steeping the coffee before completing the filtering process.
I have also done the same thing for a pour-over brewer which I also use frequently. I tried a few recipes and then started making a few minor adjustments until I dialed in “recipes” for several different specialty coffee styles and roast levels.
Summary: Dosing will vary by brewing device and the other brewing factors. Start with the brewer device instructions and check online for alternate “recipes”. Make small adjustments until you reach your perfect dosing level and “recipe” for the method.
Use Purified Water
Using pure water sounds very obvious but it is extremely important. Water purity has a significant effect on the taste of coffee. Public water supplies use chlorine, chloramines, and other chemicals to treat water. Water may also have trace amounts of metals from things like copper pipes and other compounds from plastic. These chemicals and metals react with the very complex chemistry of coffee and effect taste even in very small concentrations. Tap water that may be safe to drink can wreck the taste of coffee. On the other hand, do not use distilled water. It is missing some of the dissolved minerals and salts that react with coffee to produce a full flavor profile.
Summary: Use purified bottled water or tap water that has been filtered for chemicals and metals. Do not use distilled water.
The Right Temperature
The equivalent of the Gold Standard for temperature is 200F +/- 5 (93C +/-3). This may seem very picky but even 5 degrees can make a big difference. The boiling point of water at sea level is 212F (100C) and this turns out to be too hot for good coffee. At that temperature undesirable things happen in the chemistry. If the coffee is over or under extracting, we recommend adjusting the temperature by 5 degrees at a time in the right direction but not going over 205.
Summary: Temperature affects the extraction rate and small changes can make a difference. Start at 200F and adjust in 5F degree increments to adjust extraction but do not exceed 205F.
The Right Time
We normally think of the brew time as a measure of how strong or bold the brew will be. While that is true to some degree, brewing a great cup of coffee involves a bit more finesse that that. In Part 2, we explored the extraction process over time. We discussed how acids are extracted at the beginning of the cycle and the more complex compounds like aromatic phenols are extracted later in the cycle. We also learned that if the cycle is too long that some undesirable compounds may be extracted at levels that make our brew taste bitter.
Controlling the time of the brew cycle is important and in some brewing methods there are multiple steps or phases that can be controlled individually. This is why the hands-on pour-over methods are popular among baristas and specialty coffee drinkers. You can control almost every element of the extraction process. On the other hand, completely manual brewing can be rather time-consuming and tedious if you are just wanting a good cup of coffee in the morning and you are running late for work. That’s the balance of your personal time versus brewing time which is also an important consideration in selecting a brewing method for a specific occasion.
Since we have already talked about grind size and temperature, we can start to discuss the relationship of the ratios of time and temperature relative to a specific grind size. Since the brewing device determines the flow rate of water through the coffee, you should start with the brewing device manufacturer’s recommendations and adjust from there. To provide some context for making your adjustments, the box below shows recommended brewing times based on grind size and a water temperature of 200F.
Grind Size versus Time at 200F:
Fine: 1-4 minutes
Medium: 4-6 minutes
Coarse: 6-8 minutes
As you can see, these are pretty broad ranges. That is because the brew method and other factors affect the optimal contact time between the water and the coffee to achieve the right level of extraction. As you are experimenting and personalizing your brew, keep notes on every batch. We recommend adjusting only 1 factor at a time in small increments or it gets difficult to determine which factor made the difference or they can easily offset each other or amplify the effect.
Summary: The time that the water and coffee are in contact determines the level of extraction for various components at a given temperature, dose, and grind size. Time is critical in both the level of extraction and the balance of flavors in the profile.
In Parts 1 and 2 we explored selecting an amazing coffee and brewing basics. In this part we looked in more detail at the factors that affect the brewing cycle. You now have everything you need to start the quest for your personal amazing cup of coffee. Dialing in on your personal perfect cup “recipe” will require some experimentation and adjustment of the brewing methods and factors.
In the next Part in the series, we will explore tasting. Of course you know how to taste and you know what you like and don’t like. What many people don’t know is why they like something and how to optimize for the flavors they like and minimize the ones they don’t. Chefs and baristas are trained to identify flavors and combinations that produce tasty foods and coffee for many people. Your job is much simpler. You just need to please a few palates, starting with yours. In Part 5, we will provide some tips on optimizing and troubleshooting your brewing.