The Science of Strength – Extraction 101

Nov 10, 2016

“Is it really strong?”

We get asked this question quite a bit at the market so we thought we would address the topic here. Oftentimes, there is confusion surrounding the term “strength”; what do we mean when we say we like our coffee strong?

Some people are referring to the roast degree (light, medium, dark), which can correspond to how you perceive the strength of your brew, but ultimately it is not a true indicator of strength. Traits you would see influenced by roast degree would be acidity, complexity of flavor, body, mouth-feel, fragrance, and aroma.

Strength, or the level of intensity of all of these traits, is actually a matter of coffee extraction. Extraction is arguably the most important aspect of brewing coffee – without it, we don’t have the wonderful beverage we all love. It is everything. Unfortunately, great things have a tendency to be elusive and extraction is no exception. While it is probably the most important part of brewing coffee, it is also the least understood. In order to fully explain extraction we need to take a trip back to high school chemistry! But we’ll save that for another time (hope we didn`t scare you). For now, we’ll cover just the basics and try to help you achieve the
“strength” you desire in your cup.

To do that, we’ll focus on 3 variables as they relate to strength:
– Coffee to Water Ratio
– Grind Size & Brew Time
– Brewing Method



Most coffee professionals agree on a coffee to water ratio within the range of 1:15 to 1:18.

*we cannot recommend enough that you use a scale to weigh out your coffee and water. Using a volumetric measurement will never give you a consistent cup as coffee beans vary in density and size, and will affect your overall extraction
Depending on whether you perceive your coffee to be too strong or too weak, you can adjust your ratio by using more or less coffee. As a rule of thumb, however, try to stay in the above range. Why? Coffee is comprised of many different sugars, acids, and alkaloids. Some of those flavors are wonderful, while others…less so.

The goal with extraction is to try to get as many of the desirables as possible while leaving behind the flavors that aren’t as palatable.
If you go outside the given range of ratios, you run the risk of either extracting ALL the flavors (good and bad), or not extracting enough of the flavors (sacrificing sweetness and complexity).

Keep in mind that brewing ratio does not necessarily mean drinking ratio. If a 1:18 ratio is still too strong, you can always dilute the coffee with hot water after it is brewed (think espresso americanos)



Simply put, a finer grind = more extraction while a coarser grind = less extraction (over the same amount of time).

Different brewing methods require different grind settings based on the amount of time the water interacts with the coffee. For example, espresso requires a very fine grind. This is because the water interacts with the beans for a very short amount of time (20 seconds) so we want to grind the beans finely, and make it as easy as possible for the water to pick up all the tasty flavors. A french press, however, requires a coarse grind. This is because the grounds are completely immersed in the water for the entire process, so we want to slow down extraction to avoid pulling out undesirable flavors.

You can use a slightly finer grind for a french press if you choose, but we would not recommend going too fine. Aside from over extraction, you run the risk of clogging the filter and having quite the mess on your hands when you attempt to plunge the coffee.

*we always recommend grinding your coffee fresh with a burr grinder before brewing. If you don’t have a burr grinder, a blade grinder is fine. It wont be as consistent, but freshly ground is always best.



You can create completely different cups of coffee based on the brewing methods that you choose. For more information on some of the major brewing methods check here. For now, we’ll discuss them only as they relate to strength. Keep in mind, though, that depending on the recipe you use to brew your coffee, you can create a strong or weak cup with any brewing method.

There are three descriptors that we’ve noticed are commonly associated with strength – body, acidity, and caffeine content. While extraction is what will ultimately determine the strength of your brew, it can be helpful to look at these descriptors as you experiment to discover your preferences.

If body is what you think of when you think strength, then a french press is a good way to get a “strong” cup of coffee. It produces a heavy bodied, full flavored cup that pairs especially well with darker roasts and more robust coffees. If you prefer a less “strong” brew, but still feel that body is indicative of strength, try using a pourover like the Chemex. It has a lighter body, a cleaner cup, and lends itself to lightly roasted coffees with bright acidity.

If acidity is what you think of when you think of strength, then a pourover like the Chemex will give you more strength, while a french press will produce a mellower brew.

If caffeine content is what you think of when you think of strength, cold brew and espresso will provide you with a much stronger cup than regular brewed coffee. Just keep in mind that an 8oz cup of drip brewed coffee contains 95mg of caffeine, while a 1 oz shot of espresso contains only 64 mg of coffee. In order to take advantage of the increased caffeine content of espresso, you’ll need at least two shots!

Parting Advice

Using this guide, we should now understand that any coffee can be strong or weak depending on how you extract it. Ultimately, we just want you to enjoy your coffee. Everyone is different and experimentation will be key when trying to pinpoint your preferences. After all, brewing coffee is a science!

So yes, next time you experiment at home, we give you complete freedom to throw on a lab coat and some goggles and pretend to be a mad coffee scientist – just remember to only change one variable at a time and keep all others constant, otherwise you’ll be aiming for a moving target.
Have fun and happy experimenting!

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