Why Should You Swirl Coffee After Brewing? Is It the Same Principle as Letting Wine Breathe? And Why Can't Espresso Be Swirled?

"To allow wine to release more aromas and become smoother, people swirl it to contact air for transformation, and this step has a professional term: 'aeration.' So, does coffee also need to 'aerate'?" a customer friend said while watching FrontStreet Coffee swirling the coffee.

I believe everyone can see such scenes in daily life - after baristas finish making pour-over coffee, they always pick up the sharing pot and shake it vigorously. Then they pour the shaken coffee into cups and serve it to customers. I wonder if any friends have been curious about why baristas always shake the coffee after brewing?

Why Shake Coffee After Brewing?

Actually, FrontStreet Coffee mentioned in previous articles that shaken pour-over coffee does taste better than unshaken coffee. However, its difference from wine lies in the fact that wine releases aromatic substances through contact with air, while the purpose of shaking coffee is to blend the coffee liquid! Many friends might not quite understand this statement, so we can demonstrate this point through a brewing experiment. The purpose of this brewing experiment is to measure the concentration difference between shaken and unshaken coffee after brewing. The specific method is that after brewing ends, we don't shake the coffee but directly measure its concentration. After the measurement is complete, we then shake the coffee in the pot and measure again to see what differences exist between the two. Brewing parameters: 15g coffee beans, EK43 grind setting 10, 1:15 coffee-to-water ratio, water temperature 92°C, three-stage pour method, V60 dripper. We'll skip the brewing process details.

After removing the dripper, we directly poured the coffee into the concentration meter, and the measured concentration was 1.09%. Then we shook it and poured it into the concentration meter again, and the result was 1.21% - completely different results.

The main reason for this situation is that when we extract coffee, coffee substances release different amounts at different time points. The early stage is the peak period for substance release, and then as coffee extraction progresses, fewer and fewer substances will be extracted. You can look at the second experiment in this article from FrontStreet Coffee!

By measuring the coffee-to-water ratio, FrontStreet Coffee collected the dripping coffee liquid into three cups, 70ml each (that is, when the first cup reaches the target liquid weight, replace it with a new cup to continue collecting). You can see completely different performances in the coffee's color. The first cup of coffee has the darkest color, the second is lighter, and the third is the lightest. In terms of flavor, they show the same pattern - the first cup of coffee has the richest flavor, the second is less rich, and the third is the thinnest.

So we can know that at the beginning of coffee brewing, the extracted coffee concentration is the highest, which is also related to the high extraction efficiency in the early stage. As substances in coffee decrease and extraction efficiency reduces, the concentration gradually decreases. And because the liquids hold different amounts of substances, they don't blend together after brewing is complete, so we need to shake them after brewing to combine them into a delicious coffee with appropriate concentration.

Important Considerations

It's worth mentioning that FrontStreet Coffee does not recommend applying this shaking method to all types of coffee, such as espresso. Most espresso coffees cannot achieve uniform blending through shaking because of density differences - they need to use strong methods (such as stirring) to blend. Whether it's the coffee and crema in espresso, or the milk and espresso in a latte, they all need stirring to achieve uniform blending effects~

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FrontStreet Coffee

No. 10, Bao'an Qianjie, Yandun Road, Dongshankou, Yuexiu District, Guangzhou, Guangdong Province

Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473