March 31, 2017

Coffee 101: Extraction & The “Strong Coffee” Myth


We’ve all heard someone say “I like my coffee strong” – and maybe we’ve even said it ourselves. But what we mean by this, and what baristas understand strong coffee to be, are often two very different things.

Confused? Don’t worry. We’re going to explain what strong coffee really is, what impact it has on your drink, and how you can adjust your brewing to get the strength and flavor you want.

Get ready to learn about extraction and the strong coffee myth.

Spanish Version: Café 101: Extracción & el Mito del “Café fuerte”

Learn how to achieve perfect extraction. Credit: nonowhatever

Strong, Dark, & Rich: What’s The Difference?

First of all, we need to understand the differences between “strong”, “dark”, and “rich” coffee.

Dark: This is what many people, outside of the specialty industry, mean when they talk about strong coffee. It’s when the beans have been roasted darker, giving them a smoky, bitter flavor.

Rich: This confusing little word is used to describe a lot of different things, from dark roasts to a heavy body (also referred to as mouthfeel).

Strong: This is about the coffee extraction and brew ratio. Extraction is how we measure the amount of solubles that, during brewing, are removed from the coffee grinds and enter the water. While this sounds more like a science lesson than brewing coffee, it’s important to understand it because extraction also affects the coffee’s flavor.

Let’s look at that in more detail.

Coffee brewing

A typical home-brew setup: water kettle, brew systems, scale, and grinders.

Extraction: How Does It Affect Flavor?

Different particles are extracted earlier or later on in the brew. These will determine the final cup profile – meaning extraction affects not just how “weak” or “strong” your coffee is, but also what flavor it has.

As per SCA standards, the best extraction lies somewhere between 18% and 22% – although some people prefer it to be above 21%.

The first notes to be extracted are the fruity, acidic ones, meaning an under-extracted coffee will taste sour. Bitterness and body come later in the extraction. What you want is a balanced coffee, with a brew recipe that prioritizes your preferred profile. In other words, if you like fruity coffees, be careful not to extract the coffee too much. But if you like body, make sure you don’t cut off your pour too soon.

Yet this doesn’t necessarily mean that a shorter brew time equals a brighter, sparkling coffee. There are other factors that you also need to consider.

Coffee brewing

Measuring extraction. Credit: Gonçalo B. Duarte

Extraction: How Can I Control It?

Extraction is determined by several factors, but the main three to worry about are grind size, water temperature, and immersion time.

I spoke to Alex Choppin, a US Brewers Cup Finalist and Support Specialist for Baratza, to find out more. “I agree that extraction is largely determined by particle size, water temperature, and contact time,” he tells me. “There are a lot of other factors, but these three are big ones and are  easier to control for most coffee drinkers.”

Here’s how you can do that.

1. Grind Size

The coarser the grind, the quicker water will flow through the coffee. As of such, less extraction will take place. Say hello to more acidic coffee. Similarly, the smaller the grind size, the less gaps for water to flow through and so the longer extraction will take. This will result in a more bitter brew.

For this reason, grind consistency is crucial. If your grinds are different sizes, some of them will be extracted more than others – meaning it’ll be nearly impossible to get the profile you want.

At the beginning of my journey into specialty coffee, I ground my coffee with a blade grinder. These typically result in an inconsistent grind size, and that was showed in the cup. I switched to a handheld burr grinder, which changed my home brewing game. And when I finally switched to an electric burr grinder, it made it even easier for me to learn more about grind size and extraction.

Coffee brewing

Grind size is one of three main factors affecting extraction.

SEE ALSO: VIDEO: Here’s Why Your Espresso Shots Taste Bad

How Can You Discover The Perfect Grind Size?

When I first started experimenting with this, one barista suggested I begin grinding to the size of kosher salt and work my way up or down from there. Another gave me a small sample size to bring home and compare to my grind size. Yet another cautioned me not to ask for a specific number in coffee shops, since each machine is unique – my Baratza Virtuoso comes with 40 grind size settings, while the Baratza Sette 30 has 30.

But remember, just because you like a particular grind size for one brewing method doesn’t mean it’s the perfect choice for every method, or coffee, or recipe. I typically switch between two brewing devices: an AeroPress and a pour over. My AeroPress recipe requires a short extraction time with a slightly lower temperature, meaning a finer grind size is my go-to. But for the pour over, I want a medium coarseness.

Once you have the perfect grind size for your brew method figured out, you might still want to play with it now and then. For example, a few weeks off the roast, some people like to grind their coffee a little finer. This will help prevent the drink from developing a flat taste.

Coffee brewing

The AeroPress brew method: your recipe will impact your grind size.

2. Water

If you’re experimenting with different recipes and grind sizes for your coffee, but you’re still not getting your brew quite right, consider this list of points that Alex gave me:

“The quality of water being used to brew, the amount of turbulence with which coffee and water interact, and (to a lesser extent than grind size) the ratio of coffee to water.”

That’s three points relating to water: quality, turbulence, and ratio. For improving quality, Alex suggests using water filters: they’re affordable, easy to use, and have a noticeable impact on your drink.

Turbulence is how much the coffee/water moves and therefore interacts. More on turbulence later, but for now a quick tip: pour the water in concentric circles to ensure the most even extraction possible.

As for ratio, a common choice is 1:16, meaning 1 gram of coffee to 16 grams of water. Some grinders come with a built-in scale (such as the Sette 270W), making it easier to measure this. If your grinder doesn’t have this feature, an electrical kitchen scale will do the trick.

Once you’re confident with this basic ratio, you may enjoy experimenting a little to find the coffee profile that best suits your taste.

Coffee brewing

The coffee:water ratio is key.

3. Extraction Time

A quick internet search will provide an abundance of barista-recommended recipes, all with different extraction times. Remember, all other factors being equal, the shorter the extraction time, the fruitier and more acidic the coffee becomes. Too short, and it will turn sour. Conversely, the longer the extraction time, the more body the coffee develops, until it becomes bitter.

As Alex mentioned, turbulence also plays a key role in the extraction. Some people give their coffee a stir at this point in time, to ensure all the grinds are exposed to the water. Others take an opposing approach: they pay close attention to the rate of their pour so as to not disturb the grounds while adding water.

Coffee brewing

A barista stirs his coffee and water during extraction to create turbulence.

Extraction is a much more precise way to discuss strong or weak-tasting coffee. I’ll admit, I was intimidated when I first starting looking into the science behind how my morning brew tastes – but finding my preferred extraction ratios has transformed my coffee experience. When you begin experimenting with different recipes and methods, not only does your coffee taste better but you appreciate its flavors even more.

I’ve found my perfect recipes. Now, every time I buy a new bag of coffee, I have a baseline for dialing in the perfect cup. So what’re you waiting for? Start playing around with your grinder settings, and get ready to make your morning coffee even better.

Written with input from Tanya Newton. All photos by the author, unless otherwise noted.

Please note: Baratza is a sponsor of Perfect Daily Grind.

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