Have you ever wondered, “What is under-extracted coffee, and how do I fix it?” This article explains how under-extracted coffee happens and how to detect under-extraction to fix it.
Sometimes coffee is more of an art than a science, but that doesn’t mean that you can’t learn the technical aspects to ensure that your coffee is as good as it can be. Since all coffee brewing involves using water to extract the volatile compounds from coffee beans, knowing how that extraction process can go wrong will help you have better coffee every time.
One of the most common errors is under-extraction. But what is under-extraction?
Under-extracted coffee happens when you don’t get enough of the desirable compounds out of the coffee beans.
Read on if you want to understand more.
The Basics of Under-Extracted Coffee
The perfect coffee comes from balancing your extraction process: the grind size, water temperature, and brewing time must all match up to get the correct result. When one or more of these factors is out of balance, the result is either over-extracted or under-extracted coffee.
Over-extracted coffee happens when your coffee contains too many coffee compounds — or when the wrong compounds are extracted with the correct ones.
Instead of taking too much out of the coffee beans, under-extracted coffee happens when your brewing process doesn’t pull enough of the compounds in coffee beans that coffee-lovers enjoy.
So what leads to this?
How Does Under-Extraction Happen?
Just like over-extraction, under-extraction happens when one of the factors in your brewing process isn’t in balance. To get the perfect extraction of your coffee beans, you need water to make sufficient contact with the ground coffee for the right amount of time.
The three factors that influence the extraction process for coffee are the following:
- Water temperature
- Time
- Grind
Water Temperature
The ideal temperature for brewing coffee depends on the method you’re using. You can make a cold brew with water anywhere above freezing but below 140 degrees Fahrenheit.
However, hot brewing methods are a lot more particular: too hot a temperature risks over-extraction since more of the water-soluble compounds in the coffee will come out in hotter water. If your water isn’t hot enough, you won’t dissolve enough of the compounds you want to extract from the coffee beans.
The ideal temperature range for hot coffee brewing methods ranges between 195 and 205 degrees Fahrenheit. Automatic drip coffee machines typically keep the water at 195 degrees Fahrenheit, while espresso is closer to 205 degrees Fahrenheit. The ideal water temperature for the brewing method you use depends on the other two factors–it’s a balancing act.
Brewing Time
As with water temperature, the brewing time (which is also a question of method) plays a role in the amount of extraction. Many compounds in coffee dissolve in water, so the most popular way to have it is a beverage.
But for each brewing method, the water doesn’t just need to be at the right temperature–it has to be in contact with the grounds for the right amount of time. This also coordinates with the grind size, which we’ll cover next.
To put this in context: espresso takes about a minute to brew, from start to finish. Automatic drip coffee takes between two and three minutes on average. French press takes about five minutes to brew once you’ve bloomed your coffee grounds and filled the carafe.
In each instance, the brewing time is a factor of the grind size and the water temperature, suited to the brewing method itself. Did you know that drinking French Press coffee is not recommended for everybody?
Grind Size
As mentioned before, the brewing time depends on the water temperature and grind size. The more refined your coffee grinds are, the more contact they have with the water.
Espresso is one of the finest grinds–which is perfect, considering that the coffee grounds are only in contact with the water for a very short time in a high-pressure environment. On the other side of the spectrum, cold brew and french press coffee grounds are about as coarse as it gets–and their brewing times are longer.
If your coffee grinds are too big for your brewing method, there won’t be enough time for the water to extract the compounds you want out of the beans.
While you’re here, check out our article on the best grinder for French Press coffee.
How To Tell if Coffee is Under-Extracted
To know whether your coffee is under-extracted, over-extracted, or just right, you need to know the tell-tale signs. Over-extracted coffee has a bitter, burned flavor and some visual cues. Under-extracted coffee has the following characteristics:
- Pale color
- Watery texture, lacking in oils
- Acidic/sour flavor
- “Stale” taste, caused by under-hydration of coffee grounds
