Brewing coffee is a balancing act. It can be difficult to determine which roasting style, brewing technique, or type of coffee gear is best for you. It is helpful to understand how coffee brewing works and how different brewing methods produce different results. After that, you can choose which devices and methods would be most suitable for the coffee you want to drink.
In this text, we will focus on the physical and chemical processes involved in making coffee using the pourover method, which is simple and increasingly popular.
Why Pourover Brewing is Different
Pourover coffee brewing involves continually pouring hot water over the coffee grounds for the majority of the brewing cycle, as opposed to immersion methods like using a French press. This promotes a faster, more efficient brew. Additionally, fresh water also causes the ground to lose more of its surface layer. When brewing pour-over coffee, it is important to promote even extraction. We’ll go over how to do this below. If you use one stream of water to pour over your coffee grounds, rather than using an automatic drip coffee maker, the water can travel through the grounds unevenly. This means that more coffee will be extracted from one part of the bed than from another.
This means that when you brew coffee using a manual method like pour-over, you have more control over the variables that affect the final result. This leaves room for experienced brewers to change the flavors in their cup, but it also means that people who are new to making coffee this way might not get the results they want right away.
However, understanding how coffee brewing works can demystify pourovers. The three main phases of coffee brewing are wetting, dissolution, and diffusion.
Phases of the Extraction Process
Wetting
Making coffee wet involves adding water to dry coffee grounds. You need to think about the entire phase as a whole, as it is not as simple as it may seem. Roasting coffee produces carbon dioxide gas. The carbon dioxide that is trapped in the cell structure of lighter roasted coffees leaches out slowly over the course of several weeks. The roasting process for dark roasted coffees causes a physical hole to form in every cell, and most of the CO2 is released within a few days. The attribute of dark roasts (coffee roasted past the “second crack” phase) is also why there are some notes below about how roast level can affect brewing. This is because the roast level can affect the attributes of the coffee.
The CO2 in coffee grounds is released when hot water is added, causing the liquid to bubble. If carbon dioxide gas is exiting, water cannot enter. Picture shoppers on Black Friday. If you opened the store for business at the same moment there was a panicky fire drill, it could create a chaotic situation. This means that unless everyone who wants to get in, waits until everyone who wants to get out, gets out, they will not be able to.
Pour a small amount of water over the coffee grounds, just enough to wet them. Wait 30 seconds for the gas to escape. When you pour the water into the coffee grounds, you’ll see the grounds swell and expand, which is called a “bloom.” This step also helps the coffee grounds fully saturate, so that the water can extract solubles from the center of each grind particle, and not just from the edges.
Dissolution
If a group or organization is “dissolved,” it’s disbanded or stopped operating. When a group or organization is dissolved, it means that it is disbanded or stopped operating. After the coffee grounds are wet, the hot water will break down molecules in the beans.
It can be difficult to make great coffee because there are both good and bad tasting organic substances in it. The desirable flavors in coffee dissolve more easily in water, so if you want a good tasting brew, you need to stop brewing at the right moment- after the good flavors have dissolved, but before the nasty flavors take over.
Diffusion
Diffusion transports the dissolved substances out of the coffee grounds via a term called osmosis. The cell walls of coffee grounds are semi-permeable membranes, so the osmotic pressure drives the liquid out of the highly concentrated chambers of the coffee grounds into the more dilute surrounding environment.
This process happens naturally while the coffee is fully saturated and sitting inside of the brew water. As water is added to the filter, it mixes with the coffee solids and helps rinse them into the vessel below.
The Variables: How You Can Tweak Extraction
Around two thirds of a roasted coffee bean is made up of insoluble cellulose, which is a type of insoluble fiber. This is similar to the material that makes up tree bark or the stem of a dandelion. The other third is dissolvable in water. Most of the soluble third is good, especially the organic acids and sugars. The other molecules have a longer chain, and we associate them with astringent and bitter tastes. The happy flavor balance is found when extracting 19-22% of the coffee’s mass. If you use more than the recommended amount of coffee, the taste will become sour and bitter. If you use less than the recommended amount of coffee, the flavors will be weaker and unbalanced. With lighter roasted coffees, you may also taste an unusual amount of sourness.
In coffee brewing, there are five main variables that you control that will result in different levels of extraction: the ratio of coffee to water, grind size, brew time, brew temperature, and agitation. An automatic drip brewer that provides a consistent, ideal brewing temperature (around 198-202ºF) and time, along with an evenly dispersed showerhead, will produce high-quality coffee. If you use the right amount of water, the correct ratio of coffee, and grind it properly, you will make a delicious brew every time.
There are many variables that can affect the speed and evenness of flavor extraction in coffee. If you want to be a good photographer, it is worth investing in some equipment.
Best Water for Coffee
Coffee and espresso taste better when made with high-quality water. However, there is another very important reason to use good water and that is to protect your investment in brewing equipment.
Today we’re covering all aspects of water quality. I’ll share the methods for achieving the best-tasting water while also protecting your brewing equipment. I’ll have options for improving the quality of your tap water, including using a water filter or making your own water.
If you are using water that causes scale, you can descale it by making your own low-cost descaling solution or using commercially available products.
Distilled vs Purified Water
Let’s talk about the flavor aspect first. We are often asked why we do not use more pure water, like distilled or reverse osmosis water. Using purer water would seem to make perfect sense. If it’s purer it’s got to be better right? Since the extra pure waters have no minerals, there is no potential for scale. Scaling can have the opposite effect of causing equipment damage.
So back to flavor. Standard tap water is a relatively good solvent. It dissolves many things. Water that has been distilled or treated with reverse osmosis is an even better solvent. You shouldn’t use extra pure water to brew coffee or espresso because it over-extracts compounds and results in very bitter flavors.
Not only does water enhance the flavor of minerals, but it also helps to keep them healthy. It’s kinda like salt in cooking. Food can lack flavor without a little bit of seasoning. As expected, your doctor will tell you that consuming too much salt is bad for your health. This is also true for the health of your brewing equipment. The ideal mineral level for coffee is one that enhances flavor, prevents bitterness, and doesn’t cause scale buildup.
Getting Quality Water for Less Scale and More Flavor
At Whole Latte Love, we service hundreds of machines every year, and the number one cause of machine problems is scale. Water that has been heated and turned into steam can contain impurities that will accumulate on any interior component that it comes into contact with. This can include components such as boilers, heating elements, solenoid valves, mushroom valves, and vacuum relief valves. Scale build-up is a problem in super-automatic machines with thermo-block boilers, as the narrow passages are especially susceptible to clogging.
You can do it in two ways: install a water conditioner or use a portable system. You can get water that is good for flavor and reduces or eliminates scale buildup by installing a water conditioner or by using a portable system. There are a few options. Always use the in-tank filter recommended by the manufacturer for your super-automatic coffee machine. They remove the hardness from water while still keeping the right amount of minerals for flavor. Some manufacturers, such as JURA, recommend using a filter, so you never have to descale their machines. For others, using a filter will mean that descaling maintenance only needs to be carried out every four times as often.
For semi-automatic espresso machines, there are a few options. Our favorite filter for a plumbed-in machine is the BWT Bestmax Premium Cartridge Filter. This installs in-line between your household plumbing and machine. This system comes with a pressure regulator and flow meter to help you know when it’s time to change the cartridge. This machine uses a patented ion-exchange technology to replace the calcium that causes scale with magnesium to preserve flavour.
If you use it properly, you won’t have to descale your machine. If you have a machine that is plumbed into a water line, it is the best option and is pretty much required equipment for dual boiler machines, which would be very difficult, if not impossible, for most home users to descale. I have a Profitec Pro 700 and I use it here. The small cartridge on my water filter can hold over 1,000 liters of water with a hardness of 7°. My cartridge costs less than thirteen cents per liter.
Reservoir-fed machines require pad filters, such as the BWT Bestsave. Just add the water treatment to the reservoir and it will be good for 100 liters of water, depending on the size of the filter and the hardness of your water source.
Another popular option is the 2.7-liter BWT Penguin Pitcher. It filters the water and then adds magnesium to it to keep the flavor. It is unique from all the other filter pitchers on the market. Some carbon filters do not remove hardness, while others remove most minerals, leaving no flavor. The BWT does an amazing job at filtrating water and leaving you with water that doesn’t have any scale and tastes great either through your machine or for drinking straight.
A final solution is to create your own brewing water using either distilled or reverse osmosis water. The speaker is talking about brewing water for SCA events, and provides a link to a video on the topic. This water purifier will produce water that tastes great and has a low chance of causing scale buildup due to the magnesium supplying the hardness.
Do not use straight distilled or RO water in your machine as it will not be as effective. As I mentioned upfront it’s an incredibly good solvent. Without minerals being added back into the water, it can cause corrosion of metal components instead of scale. The reason you never see ultra-pure water stored or transported in metal containers or pipes is because it would cause the water to become contaminated.
Descaling Your Espresso Machine
You can make your own descaler using citric acid. Citric acid is a cheaper alternative to vinegar, it is odorless, and it is used in many commercial descaling products. The crucial element is that you’re only blending citric acid powder with water, so there is no one definitive concentration or recipe that will work for every machine. You’ll have to experiment a little bit to figure out how much to use.
I believe that you should feed your machine water that will either reduce the need to descale or eliminate it completely. This will result in better tasting coffee. You should use a filter that is compatible with your machine or situation for the best results.
If you need help with choosing the right coffee filter or installing a complete in-line system, our coffee pros are ready to assist you.