How Long Should Coffee Beans Rest? What is Bean Resting? Does Espresso Need Bean Resting? What is the Purpose of Bean Resting?

Understanding Coffee Bean Resting: A Comprehensive Guide

"Coffee bean resting" – chances are you've heard this term mentioned before. In today's world where coffee has become a daily ritual, even beginners who may not understand the specific purpose of resting beans know that when encountering freshly roasted coffee beans, it's best to let them sit for a while before brewing. Therefore, FrontStreet Coffee's physical stores often encounter customers holding coffee beans and asking: "Do these beans need resting?"

To help everyone understand this concept more thoroughly, FrontStreet Coffee would like to review the purpose of bean resting today. Additionally, we'll explore whether coffee beans truly need resting!

What is the Purpose of Coffee Bean Resting?

Bean resting, as the name suggests, means nurturing coffee beans before brewing (just kidding)! The purpose of resting beans is to better extract soluble substances from the coffee. When coffee beans are first roasted, they accumulate a rich amount of carbon dioxide internally. This carbon dioxide will hinder our extraction of flavor compounds. During brewing, the presence of carbon dioxide makes it more difficult for flavor compounds to dissolve.

This means that under the same brewing parameters, overly fresh coffee beans will lead to decreased extraction rates, resulting in coffee that lacks fullness in flavor. Meanwhile, the roasty notes produced during roasting may become more apparent due to insufficient flavor development. Simply put, brewing becomes less stable, and the coffee's performance is somewhat diminished.

However, because carbon dioxide gradually dissipates over time, we simply need to let the coffee beans rest for a period, allowing most of the carbon dioxide to escape, which makes brewing more stable. Therefore, to achieve a better experience, most people will let freshly roasted coffee beans rest until most of the carbon dioxide has dissipated before brewing. This practice is what people call "bean resting."

Do Coffee Beans Really Need Resting?

For pour-over coffee, whether you rest beans or not is actually acceptable – it mainly depends on your understanding of extraction. If you're an extraction expert who knows how to respond when brewing coffee beans, you can significantly reduce the impact of carbon dioxide by changing brewing methods. (For details, you can refer to this article → "How to Brew Overly Fresh Coffee Beans?") However, if you're a beginner who doesn't yet have a thorough understanding of brewing, it's best to let the coffee beans rest for a while until they stabilize before brewing, so you won't waste the beans.

There's another exception – if you've never tasted un-rested beans. Many people ask whether beans need resting mainly because they've never tasted un-rested beans and only know what undesirable characteristics they might have. In this situation, FrontStreet Coffee would recommend starting from when you receive the beans – even if they were just roasted that morning, you can begin brewing. Brew once daily using the same parameters for extraction, and record the coffee's flavor performance each day. This way, you'll understand how carbon dioxide affects extraction and know what un-rested beans taste like when brewed.

Additionally, as FrontStreet Coffee mentioned earlier, for pour-over coffee, the impact of carbon dioxide can be reduced by adjusting extraction methods. However, for espresso, overly fresh beans do need resting. Because espresso typically uses medium to dark roasted beans, and the darker the roast, the more carbon dioxide the beans contain, which has a greater impact on extraction (plus, crema stability decreases, which isn't friendly for latte art).

Moreover, because espresso uses pressurized extraction – a method that extracts coffee in a short time – it's more sensitive to extraction. In other words, the effects of excessive carbon dioxide are amplified, making extraction less stable. This means we might need to use more coffee grounds to adjust the espresso, which wastes both beans and the barista's effort! Therefore, if coffee beans for espresso are too fresh, it's best to let them rest for a while.

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Tel:020 38364473