What Coffee Beans Are Suitable for Espresso Machines? Flavor Characteristics and Performance of Espresso Beans

Using Light Roast Coffee Beans for Espresso: A Comprehensive Guide

Earlier, FrontStreet Coffee wrote an article titled "What happens when you use light roast coffee beans for espresso?" That article mainly featured FrontStreet Coffee's selection of several light roast coffee beans to make espresso and test their feasibility. This article serves as a new addition to that piece, sharing the differences when using light roast beans for espresso extraction.

Does Light Roast Espresso Taste Sharply Acidic?

When FrontStreet Coffee educates about espresso knowledge, it's often mentioned that coffee beans used for espresso extraction are typically roasted darker. This is because light roast coffee extraction for espresso results in an overwhelmingly sharp acidity. Espresso uses pressurized methods to extract flavor compounds from coffee grounds, and light roast coffee contains more acidic substances. When these acidic compounds are concentrated into a small cup of coffee, the acidity is amplified, making it intensely sour.

This is why everyone recommends using coffee beans roasted at medium-dark level or above, as the coffee flavor profile will be relatively balanced, neither sharply acidic nor burnt bitter.

Another factor is extraction difficulty. When FrontStreet Coffee shares knowledge about espresso extraction, it frequently mentions channeling and under-extraction issues. Even when using dark roast espresso beans, under-extraction can still produce sharp acidic flavors. Light roast coffee experiences more frequent channeling and under-extraction when used for espresso. Therefore, the sharp acidity when making espresso with light roast coffee beans is primarily due to the inherent flavor profile of the beans combined with improper extraction techniques.

Common Problems When Extracting Espresso with Light Roast Coffee Beans

Using the Same Grind Size

Some friends want to try making espresso with light roast coffee beans, so they directly replace their original espresso beans with light roast ones, perform some grinder cleaning steps, and then brew using the original dose parameters.

When they take the same weight of coffee grounds, they notice that the tamp goes down much more easily, feeling smaller in volume than dark roast grounds. After locking into the espresso machine and pressing the extraction button, the coffee liquid gushes out like a fountain, reaching the 1:2 target ratio in less than 10 seconds.

This is because light roast coffee beans don't expand as much as dark roast beans, so at the same weight, light roast coffee grounds occupy less volume. The rapid flow of coffee liquid is due to the lower water absorption and expansion of light roast grounds, making it very easy for water to pass through.

Therefore, the first step when extracting light roast coffee beans with an espresso machine is to adjust the grind size. If you typically use medium-dark roast beans for espresso, when switching to light roast beans, you need to make the grind finer. For example, when FrontStreet Coffee extracts a light roast washed Yirgacheffe, it adjusts the espresso grinder 0.3 settings finer. (Note: FrontStreet Coffee's daily grind adjustments are within ±0.05)

Using the Same Dose

Without adjusting the grind size, the light roast coffee puck is already smaller in volume than the original. After making the grind finer, the puck becomes even smaller. This means there's a longer distance between the puck and the shower screen, creating greater impact force on the puck during extraction, which can lead to perforation in severe cases. Additionally, when the puck thickness is thinner, water passes through more quickly, resulting in insufficient extraction time, making the coffee taste thin and sharply acidic.

The simplest solution to this problem is to increase the dose. How much to increase depends on the extraction time and the reasonable dose capacity range of the portafilter (where the tamped puck aligns with the portafilter's ridge). For example, FrontStreet Coffee uses 20g for Sunflower Warm Blend coffee beans, but needs 21.3g for light roast Yirgacheffe to reach the portafilter's ridge line.

Using the Same Pressure

Espresso can extract coffee compounds in about 30 seconds that would take 2 minutes with pour-over methods, largely due to pressure. Typical espresso extraction pressure reaches 9bar - the higher the pressure, the more efficient the extraction.

When you've adjusted parameters like dose and grind size, and the ratio and time are within reasonable ranges, but the extracted espresso still exhibits the acidic profile of light roast coffee along with woody, herbal bitter notes, slightly lower pressure during extraction can effectively solve these problems. When FrontStreet Coffee makes espresso with light roast coffee beans, it controls the extraction pressure between 6-7bar.

FrontStreet Coffee's Summary of Changes for Light Roast Espresso

Below, FrontStreet Coffee summarizes the changes when making espresso with light roast coffee beans for everyone's reference:

1. The universal principles for espresso extraction also apply to light roast coffee: maintain a coffee-to-liquid ratio of 1:2, with extraction time controlled between 25-30 seconds.
2. Compared to the dark roast espresso beans we're accustomed to, light roast beans require a finer grind size, increased dose, and reduced pressure. (The grind size and increased dose are related - the finer the grind, the smaller the volume after tamping, requiring more coffee grounds. However, both are constrained by time - the finer the grind and more grounds, the longer the extraction time. Therefore, setting a 25-30 second extraction time is an excellent way to verify whether your grind size and dose are correct.)
3. Hitting the extraction template doesn't necessarily guarantee good coffee. If you decide the flavor still needs improvement, you can make fine adjustments to grind size, coffee extraction amount, and pressure.

What Does Espresso Made with Light Roast Coffee Beans Taste Like?

First, if you don't normally drink espresso, you'll find espresso made with light roast beans extremely intense and acidic, almost startling. If you have a habit of drinking espresso, the acidity of light roast espresso will be very pronounced, accompanied by a faint saline sensation. The body naturally won't be as high as traditional espresso beans, but it still offers a creamy, cheese-like texture.

Second, espresso made with light roast beans performs quite well when mixed with water to make Americano coffee. The acidity is bright and full, with good sweetness and bittersweet coffee flavors in the middle to late sections, and a noticeable aftertaste. (This is the flavor profile when using Yirgacheffe to make Americano - not all light roast beans will taste this way; it depends on the specific flavor description of the beans.)

Finally, espresso made with light roast beans isn't actually suitable for milk-based drinks. This is because light roast coffee's profile is dominated by acidity, floral notes, and other fresh flavors that are easily masked by milk's taste, leaving you with milk that has a hint of coffee flavor. (Friends who prefer prominent milk flavors and dislike coffee bitterness might enjoy this.)

Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473