Basic Guide: How to prepare a better coffee at home

The world of coffee brewing can be complex. There are many factors that can affect the taste of your drink, factors like grind size, brewing time, water temperature… This doesn’t necessarily make it difficult. I’m going to explain the basics of brewing parameters so you can make wonderful coffee every time.

THE ONLY RULE YOU NEED TO UNDERSTAND

Brewing coffee is a matter of science. Fortunately, once you understand a concept, everything becomes easier.

While many things affect the flavor and aroma of coffee, almost all of them can be traced back to one word: extraction.

According to Lani Kingston in How to Make Coffee: The Science Behind The Bean, coffee is about 30% soluble. And this 30% contains all the flavors and aromas we want to taste in our cup of coffee. The only question is: How much of these aromas and flavors do we want to taste?

It is in the preparation of coffee that we extract these compounds and if we control our method, we control the level of extraction. This is important because not all compounds are extracted in the same proportion or point.

At the beginning of the brewing process, the fruitiest and most acidic compounds are extracted. Then, comes the sweetness, and finally, the bitter compounds are extracted. In other words, if your coffee tastes too acidic (and it's not because of the roast or the beans), it's probably under-extracted. Conversely, if it tastes too bitter, it's probably over-extracted. But if you get a sweet, balanced, complex, and delicious coffee, it means that you managed to extract perfectly. This is the only rule you need to understand when brewing coffee.

So let’s take a look at how to control extraction to get the coffee profile you want. Let’s start with the most important parameters: contact time and grind size.

CONTACT TIME

Contact time, or brewing time, refers to the amount of time the coffee grounds remain in the water. Despite this simple definition, this parameter is one of the most important.

The longer the contact time, the higher the extraction, all things being equal. This is easy to control with immersion brews, but with filter or pour-over brews, where the coffee slowly drips through the filter, there are other factors that affect it, such as grind size. But more on that later.

So, if you want more bitter flavors in your cup, make a longer brew. And for a fruity cup, make a shorter brew so that the fruity flavors aren't covered by other flavors. But of course, don't make the brew too short. Remember, you're looking for a balanced cup.

A good way to learn more about how contact time works is to play around with the Clever or AeroPress. Keep the grind size, temperature, and coffee the same; time the brew; and test the difference contact time makes.

GRIND SIZE

Now let's talk about our second variable, grind size. This is about the available surface area that comes into contact with the water. When you have a coarse grind, with large pieces of coffee, the surface area ends up being smaller than with a fine grind. Contact is crucial for solubility, so with a fine grind, the extraction will be more efficient.

However, if you're making a drip/pour-over coffee, or even an espresso, the grind size can also affect contact time. The larger the coffee particle size, the larger the space between them, allowing water to flow through the grinds much faster. This will further reduce the amount of time for extraction. (Another point to consider is that if the grind is too fine for the filter, you may end up with some in your cup, resulting in a continuous extraction and a lumpy experience in your drink. That's why it's important to use the right grind size for your brewing method and filter.) Tip before grinding coffee: Pay attention to consistency! If your particles aren't uniform, you're going to have different extraction rates. And you're going to end up with an unbalanced drink. To ensure you have a good grind consistency, invest in a good grinder, or even a sifter.

If you put sugar in a cup of cold water, it will dissolve. But if you put it in hot water, it will dissolve faster. A similar principle applies to coffee: the higher the temperature, the faster the extraction. In other words, if your coffee is too bitter but you want to keep the same contact time and grind, you can try lowering the water temperature. If it's too acidic, you can increase the temperature.

Additionally, certain compounds are only extracted at a higher temperature. According to Tristan Stephenson in The Curious Barista's Guide to Coffee, “certain astringent compounds will only be extracted near 100ºC / 212ºF, which is why we avoid using water above 95ºC / 205ºF.”

The SCA recommends using water between 90ºC / 195ºF and 96ºC / 205ºF for brewing (although, to evaluate the coffee, it says a variety of temperatures are useful: 71ºC is best for the initial sip; 71ºC-60ºC for acidity, body and balance; 38ºC for sweetness, evenness and cleanliness).

My advice: you can play around with all the parameters in today's article, however, you can change the temperature at the end. When fine-tuning a coffee recipe, start by manipulating the brewing time and the grind size.

A QUICK NOTE ABOUT COLD BREW

Cold brew is known for its low acidity and smooth flavors. For some people, this is a negative trait, for others, a positive. But why does it taste so different? Because, well, it's brewed cold. As Lani Kingston says in How to Make Coffee, certain compounds need higher temperatures to be extracted, and this leads to the acidity in cold brew being minimal.

Cold brew requires longer contact time, often 12 hours or more, to properly extract. However, contact time cannot fully compensate for the lack of heat.

Agitation refers to the act of altering the grind during brewing. By doing this, you ensure that every particle comes into contact with the water. Since we've already talked about the importance of contact, you probably know what I'm going to say: agitation can improve consistency and make the extraction more efficient, i.e. faster.

Not all coffee is roasted the same. Darker roasted beans, which have been roasted for longer, will have more degraded structures. As a result, they are more soluble than lighter roasts.

Dark roasts tend to be more bitter, so if you brew for a long time, with a fine grind and water that is too hot, you may end up with an unpleasant experience.

On the other hand, light roasts tend to produce acidic coffee if brewing time, grind size, and water temperature are not controlled.

Pro tip: Don't forget to check the date when your coffee was roasted. Coffee continues to deteriorate after roasting, losing many of its flavors and aromas, and affecting extraction.

FILTERS

If you want a clean cup, use filter brewing methods. But keep in mind that not all filters are created equal – some are finer than others and made from different materials.

Filters that can retain extremely fine coffee particles are a good idea to avoid bitter tastes. On the other hand, a filter that is too fine will increase contact time (the flow of the drink will also be slow).

Paper filters will capture a lot of the oils in the coffee, keeping them out of your cup. Oils are insoluble, meaning they help create body or mouthfeel. So if you want more body, choose a metal filter.

YOUR COFFEE BEANS

We have discussed many brewing parameters, but it is worth mentioning that the ideal setting will always depend on the coffee beans you have. Not all coffees are created equal: some are sweeter, others have more body, others are more soluble…

The first thing you need to know when making coffee is the characteristics of your beans. This includes:

Where the coffee came from: Coffees from different countries tend to have different flavors and aromas; for example, Ethiopian coffees are known for their acidity and Colombian coffees for their balance.

If you have the SCA cupping form or tasting notes, these professional comments will let you know what to expect.

Processing method: Natural coffee tends to be sweet and full-bodied; washed coffee is often clean and brings out the natural acidity of the bean, and honey/pulped naturals have varying degrees of sweetness and body depending on the exact processing method.

Species and variety: Different varieties often have specific flavor profiles.

Making coffee seems simple, just a mixture of hot water and ground coffee.

However, when we start looking for ways to improve our coffee, to prepare delicious cups full of flavour and aroma, everything becomes a little more complicated. These parameters we have analysed will help you discover the best recipe for each coffee you prepare.

I recommend experimenting with these parameters to better understand how they affect extraction, as well as what kind of coffee profiles you prefer. If you're ready to invest in a refractometer, you can also use it to check how well you extracted your coffee.

Mastering these points will help you make better coffee every time. Because remember: even if you have great beans, your coffee is only as good as your brewing method.

Translated by Alejandra M Hernandez and Edited by Ricardo Gallopp R.

Courtesy and Credits: PDG Español

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