Sour makes fun? Myth and truth about acid in coffee

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This rule only applies to coffee to a limited extent. Acidity has a very negative connotation in connection with coffee. Why the topic of acidity in coffee is often misunderstood and why coffee without acidity would not be coffee, we show you in the following article.  

Table of contents

Sour or bitter?

Many coffee drinkers find it difficult to distinguish whether something is sour or bitter. Often you just feel an unfamiliar or unpleasant taste in your mouth, but can't place it. Bitter foods include grapefruit and radicchio, for example, but also drinks like Campari. Sour foods, on the other hand, include lemon, currant and apple cider vinegar.

Coffee without acid - is that even possible? What acids do we find in coffee? 

Acidity belongs to coffee like the hammock belongs to our Chef Flo. However, not all acid is the same. Every coffee bean contains a certain amount of chlorogenic acid. It is a natural antioxidant and is found not only in coffee beans, but also in potatoes and artichokes, for example. Arabica beans, at around 5%, have a lower chlorogenic acid content than Robusta coffee, which has around 8%. Chlorogenic acid is broken down during roasting. It is destroyed by the action of heat, which also results in the typical aroma compounds of coffee, among other things. Gentle, slow drum roasting, as in the case of our specialty coffees, is therefore preferable to industrial fast roasting processes, as it makes the coffee more digestible.  

In addition to chlorogenic acid, coffee also contains other acids that are responsible for its fine variety of flavors. These include, for example, citric acid, which is often found in Arabica beans from higher altitudes and brings a fine citrus flavor, but also malic acid or acetic acid, which give your coffee aromas of stone fruit or a certain spiciness. 

So let's briefly summarize once again:

Chlorogenic acid is responsible for an unpleasant acid taste in coffee, but is reduced by gentle, long roasting. Fruity acids such as malic, citric or tartaric acid give our specialty coffees the sweetness and freshness that make for the best coffee enjoyment. Acidity is therefore an essential component of coffee and is what makes it the cult drink for which we celebrate and love it.

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Tips and tricks against sour coffee 

In addition to your choice of beans, there are other tricks you can use to influence the acidity of your coffee. Here are three tips on why your coffee can taste sour and what you can do about it:  

Portafilter vs. filter coffee - Why is the acidity in espresso lower than in filter coffee?  

There are two reasons for this: Beans for espresso preparation are roasted darker, i.e. longer, than beans for filter coffee. This leads, as you may have already read in the article above (if not: off to the top), that during the longer roasting process chlorogenic acid is degraded. Therefore, in espresso beans like our Choc n` Brew for example, contain less acid than in light roasted beans (for example in the Plum Crazy) for filter coffee. 

Another aspect in the development of acidity is the preparation: When preparing espresso with the portafilter coffee machine, the coffee grounds are pressed through the sieve with high pressure and 90°-94° hot water. This results in an average contact time of about 25-30 seconds. With this short contact time, less acid is dissolved from the coffee grounds than in the preparation of filter coffee, which is infused for around 3-4 minutes.  

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The brewing temperature - give me acid - uhh - hot, baby!  

If the water for your coffee preparation is too cold, your coffee can quickly taste sour. The optimal brewing temperature is somewhere between 92°-96°, depending somewhat on the preparation method. The easiest way to reach this temperature is to boil the water with a kettle, for example, and then let it stand for about 1 minute. Then your water has reached the optimal brewing temperature. Or you can use a kettle with temperature control, for example the Brewista Smart.

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Under-extraction - a technical term that will make you and your coffee sour  

The bean alone does not make the coffee. Perhaps you have already cast an eye over the barista's shoulder during espresso preparation or even experimented yourself: Sometimes it happens that the espresso literally shoots out of the sieve and the extraction is finished in 10 seconds. In such a case, we speak of under-extraction, which means that not all the substances that lead to an optimal taste experience have been dissolved from your coffee grounds. There are two reasons for this: either you have used too little coffee powder, or your ground coffee is too coarsely ground. Whatever the cause, your coffee will taste watery and - guessed right Sherlock - sour! Therefore, make sure that your coffee powder has the right grind and that you do not use too little ground coffee - you would be saving money in the wrong place.  

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