For the regular person, all espresso is good espresso. However, for someone having a refined tongue, espresso is a blend of flavors where not one hint of flavor may exceed another. As a result, some may leave your mouth on a high note, while some may leave you asking: “Why does this espresso taste sour?”
Espresso is an acidic beverage, and acidity is preferred. However, this does not mean that a sour espresso is excusable. Because of certain factors, mostly stemming from under extraction, sour espresso may become more jarring.
Let us get scientific in this article. We will answer the most relevant questions, from why espresso tastes sour to how you can mitigate the sour taste.
Why Does Espresso Taste Sour? Here Are The Straight Goods
Sour espresso is not something someone would want to drink. While some may think that since some of the best coffee worldwide is acidic, undoubtedly sour espresso surely must be a good thing. However, that is not the case.
Espresso that tastes sour is a poor excuse for an acidic blend. Technically, one did achieve the desired acidity, but that certainly does not mean it is appropriate for consumption either.
In this analogy, take a look at it: most good cakes are sweet, but a sweet cake is not automatically good. That is why in this section of the article, we look at the answers to the question: “Why does espresso taste sour?”
1. Under Extracted Coffee
Sour espresso is usually caused by under-extracted coffee. In fact, most, if not all, of the reasons why espresso is sour is related to the under extraction of coffee.
So if you find your espresso sour and end up asking yourself the reasons why your espresso might taste that way, it might be because your espresso is under-extracted.
The science of coffee brewing is this: the first of all the flavors to come out while brewing is acidity and sour, tangy taste. When coffee is under-extracted, all that comes out is the tangy texture and none of all the bitter and sweet flavors that will otherwise make your espresso taste great.
2. Too Little H20 To Work With
If you are acquainted with the basic principles of brewing, you might have heard of the term coined as “golden ratio.”
The golden ratio is the perfect water balance to coffee grounds that will work with most coffee beans. However, the golden ratio only is a general guide and not a “one size fits all” solution to your espresso ratio problems.
One important thing to note is that the golden ratio will heavily vary depending on what type of coffee bean you are using. When using too little water for a particular batch, you might notice the more robust sour flavor that will quickly overwhelm your tongue.
This phenomenon is because when using too little water, the resulting espresso will be very concentrated. Although espresso by itself is concentrated, having it be too concentrated will result in a less than desirable coffee that no coffee lover would like to indulge themselves in.
Another effect is that this will most often reduce the brew length significantly, which you might have already guessed results in extremely aromatic espresso. Speaking of brew time, let us talk more about it in our next point.
3. Too Fast!
Keep noticing that your brew times last for ten seconds, and a bubbly, pale yellow liquid comes out? Well, what you have there is an espresso that is brewed too fast.
Espresso is usually brewed between 20 to 40 seconds, depending on preferences and the beans themselves.
When brewed too fast, the resulting espresso will be sour and be barely palatable.
As a result of under extraction, brewing too quickly creates a big problem in the taste of the resulting espresso, especially since the hot water at that point would have barely brewed the grounds enough to extract their delicious nutty goodness properly.
4. Skimping On The Heat
Unless you are cold brewing, heat will play a significant role in the brewing process to extract all the flavor from the coffee grounds.
Since heat is needed to dissolve flavor compounds from the coffee grounds, using water that is not hot enough to comply with brewing standards, even if brewed within the appropriate time frame, will still result in under-extracted coffee.
Why does your espresso taste sour? Better check your brewing temperature next time.
Temperature Tip: The ideal espresso brewing temperature for extraction is between 80 to 95 degrees Celsius. However, if the beans are lightly roasted, the temperature required for optimal extraction will be between 90 and 95 degrees.
5. Too Crude
Have you noticed how brown sugar dissolves slower when compared to white sugar? This is because the size of the particles of brown sugar is significantly larger when compared to sugar.
Likewise, brewing with crude, larger coffee grounds will require more effort to brew when compared to finer coffee grounds.
Playing with larger coffee grounds will require much prediction and luck, as brewing grounded coffee grounds with non-uniform sizes will require many estimation skills. In addition, each cup has different heating and time needs when brewing.
To make the process more consistent and more manageable (mainly to prevent under-extracted, sour coffee), make sure to use evenly finely grounded coffee grounds.
6. Stale Beans
Coffee beans break down over time as they are exposed to the elements: heat, humidity, and air.
By the time they get grounded or get brewed, stale beans would probably have experienced a lot of environmental trauma that would make their resulting coffee less desirable than freshly ground coffee beans.
The natural acids would have already broken down when this happens, so brewing them will result in a heavier, harsher taste with a lot of sourness reminiscent of lemon.
Sour Like Drinking Vinegar? We Can Fix That!
Maybe your espresso is too sour for your taste. Please do not panic, as we can fix that quickly! Instead of asking why your espresso tastes sour, let’s start fixing the problem.
Make It Longer
An easy way to make sure the brewing process is appropriate and the grounds are finely extracted? A somewhat obvious way to fix under extraction is to brew it longer than it has been the last time.
Brewing longer will not only bring out the acidity from your coffee grounds, but it will also flourish with a sweet and bitter flavor profile.
Make It Finer
If you buy your coffee beans from the supermarket or a local roaster, you may skip this step entirely. However, if you ground your coffee beans yourself, make sure to take enough effort to ground them finely.
It will make it so that the hot water will seep through the coffee grounds evenly, resulting in a coffee extracted well.
Make It Hotter
Temperature is a make or breaks variable for food: from cooking, baking, freezing, and brewing.
Stressing the importance of temperature, you will need to maintain a consistent and appropriate brewing temperature (not too hot or your coffee will taste bitter or burnt) to make sure that your coffee tastes whole, complete with mild acidity, a sweet flavor, and controlled bitterness.
The Coffee Alchemy
From the green coffee bean to the freshly brewed coffee you indulge in and enjoy, every chemical transformation plays a significant role in forming the flavors concentrated into the very cup of coffee you want.
Here, we discuss the flavors that slowly get introduced as the Maillard Reaction (the reaction responsible for the browning of food) and acquaint you to produce the right flavor notes for your coffee.
Initially, green coffee beans are very sour. So, naturally, during the first few seconds of brewing, the first flavors to come out are the sour, tangy accented tastes. If your coffee is under-extracted, the sour taste will be most apparent.
The Oils And Sugars
After the extraction of the acids, what comes next are the oils and the sugars. These are one of the most important flavor notes to add to a cup of coffee as they make the coffee feel more exquisite, more complex, and more “whole.”
When under extracting, the oils and sugars are not present, resulting in a thin, shallow, sour cup of coffee. In instances of over-extraction, the oils evaporate, resulting in a bitter, aggressive taste.
The last flavor note to come out, bitterness, basically ties up all the flavors into one producing a well-rounded coffee. Appropriately extracted coffee grounds will result in these three flavors making an appearance.
The Sour Cup: Three Questions People Ask
Does acidic coffee mean sour coffee?
No. Acidic coffee can be sour, but most enthusiasts who prefer acidic coffee also like notes of added sugars, oils, and bitterness. However, just because many prefer acidic coffee doesn’t mean sour coffee is good.
How long can ground coffee stay fresh?
One to two weeks after grinding.
What is the golden ratio?
The golden ratio refers to one to two tablespoons of coffee for six ounces of hot water.