Pour-Over Coffee Lacking Crema: Issues with Insufficient Crema in Pour-Over Coffee

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Coffee enthusiasts who often drink espresso know that espresso is covered with a layer of crema, and espresso is no exception. That layer of oil is usually called "Crema." So why doesn't pour-over coffee have this layer of crema? Aren't they both made from coffee beans? Could it be that espresso beans have richer oils? In this article, FrontStreet Coffee will explain why pour-over coffee doesn't have a "Crema" layer.

How is the crema on espresso produced?

First, we need to understand where the crema on the surface of espresso comes from. Generally, when FrontStreet Coffee uses a coffee machine to extract espresso, the coffee grounds are ground extremely fine and extracted under high pressure of up to 9 bar. When hot water passes through the coffee puck, the carbon dioxide in the coffee grounds cannot escape due to the high pressure, and the water becomes supersaturated with carbon dioxide. The carbon dioxide cannot be released and directly dissolves into the coffee liquid. The high pressure also forces the oils contained in the coffee to separate from the coffee puck and be carried out by the hot water.

After coffee extraction is complete, when the coffee liquid flows out of the coffee machine and returns to normal atmospheric pressure, the carbon dioxide remaining in the coffee liquid prepares to return to the air. However, the carbon dioxide encounters the oils in the coffee liquid. The oils trap the carbon dioxide that is trying to return to the air. This is how the crema layer is produced. To put it simply, the reason we can see obvious crema on espresso is because of the emulsified oil foam produced by high-pressure extraction. In reality, coffee oils are not that obvious, and if present, they appear as a very thin transparent liquid floating on the surface of the coffee.

Why can't we see a crema layer in pour-over coffee?

First, the main reasons why pour-over coffee appears to have no crema are: 1) Coffee beans are difficult to "squeeze out" too much oil without high-pressure extraction, and 2) The filter paper will filter out the oils.

Because coffee filter paper has a tight structure, most colloids are blocked during the brewing process, and only the smallest colloid molecules can penetrate the filter paper. Therefore, the small amount of oils that could originally be extracted in pour-over coffee are gone after passing through the filter paper, and the coffee that finally flows into the pot will naturally be much cleaner. In espresso, under the powerful pressure of the espresso machine, a large amount of colloids can be extracted, making the oils richer, the taste fuller, and the body more substantial.

How to preserve oils in pour-over coffee?

As FrontStreet Coffee mentioned above, most pour-over coffee uses a filter cup combined with filter paper for brewing. Because of the filter paper, almost all pour-over coffee has no crema. But if you want to preserve oils in pour-over coffee, are there feasible methods? Of course, there are. According to FrontStreet Coffee, in addition to filter paper, there are actually two other filter materials available on the market: metal filters and cloth filters.

Metal filters are shaped like filter paper and have numerous tiny holes to separate coffee grounds from coffee liquid, while cloth filters are represented by the well-known flannel filter cloth. Both can preserve a certain degree of coffee oils and can also be reused. However, the disadvantages are also very obvious: because of the oils, they must be cleaned thoroughly multiple times after each use to ensure that all residual oils are removed, otherwise they will affect the taste of the coffee during the next brewing.

Therefore, FrontStreet Coffee still recommends that coffee enthusiasts use filter paper for pour-over coffee. Next, FrontStreet Coffee will share some correct methods for making coffee and basic knowledge of pour-over coffee.

Basic knowledge of pour-over coffee

First, what do you need to prepare besides equipment for pour-over coffee? For this, FrontStreet Coffee has combined past pour-over coffee experience and basic knowledge to summarize the following seven elements of pour-over coffee to help coffee enthusiasts understand pour-over coffee more intuitively.

1. Fresh coffee beans

FrontStreet Coffee believes that the optimal flavor period for coffee beans is 30 days. After 30 days, because aromatic molecules decrease with the release of carbon dioxide, coffee beans past their flavor period may taste bland and plain when brewed. This is also why FrontStreet Coffee always emphasizes "using freshly roasted coffee beans" before sharing brewing knowledge.

2. Grind size standard for pour-over coffee

At the same time, to ensure that each type of bean has the most suitable grind for brewing, FrontStreet Coffee recommends purchasing a #20 cupping calibration sieve with a mesh diameter of 0.85mm. We take 10g of coffee beans, adjust to an approximate grind size, grind into coffee powder, then pour it into the sieve for screening. Weigh the screened coffee powder (make sure to sieve until no more coffee powder can pass through), and if the screening pass rate is 80% (10g of powder can sieve out 8g), that is the most suitable grind size for light to medium roast coffee beans. If the screening pass rate is 70%-75% (10g of powder can sieve out 7-7.5g), that is the most suitable grind size for medium to dark roast. If the pass rate exceeds the suitable range, appropriately adjust to a coarser grind; if the pass rate doesn't reach the suitable range, appropriately adjust to a finer grind.

3. Brewing water temperature

When FrontStreet Coffee brews coffee beans with different roast levels, we also choose different water temperatures. During roasting, the substances contained in coffee beans are lost as the roast level deepens. Therefore, to avoid extracting too many undesirable flavors from dark roast coffee beans, we lower the temperature. For light to medium roast beans, FrontStreet Coffee recommends using water temperature of 90-91°C. For medium to dark roast beans, we recommend using water temperature of 87-89°C.

4. Water quality

The mineral components in water - mineral ions such as calcium, magnesium, sodium, and potassium - will affect the thermodynamic extraction ability of coffee, thereby causing changes in coffee flavor. FrontStreet Coffee does not recommend using tap water directly heated for brewing. Tap water has many impurities, and the extracted coffee can easily have an unpleasant taste.

5. Choice of brewing filter cup

FrontStreet Coffee recommends beginners choose the V60 01 size filter cup. The V60 conical filter cup has a large opening, and its unique spiral rib design allows air to be discharged more easily, thereby improving extraction quality. The body might not be rich enough, but its high concentration that brings out acidity and sweetness with distinct aroma is its major characteristic.

6. Coffee-to-water ratio

This is based on the SCA Golden Cup extraction theory's pour-over coffee water-to-coffee ratio extraction parameters and taste differences:

[Bold Flavor] 1:10～1:11 (equivalent to Golden Cup standard's 1:12.5～1:13.5)

[Medium Flavor] 1:12～1:13 (equivalent to Golden Cup standard's 1:14.5～1:15.5)

[Light Flavor] 1:14～1:16 (equivalent to Golden Cup standard's 1:16.5～1:18.5)

A coffee bean-to-water ratio of 1:14.5～1:15.5 most easily achieves the golden range of 18%～22% extraction rate and 1.15%～1.35% concentration.

This is also why FrontStreet Coffee has always recommended everyone use the 1:15 brewing ratio. Therefore, FrontStreet Coffee summarizes the information given to us by the above SCA extraction ratio parameters:

(1) The larger the coffee-to-water ratio, the lighter the coffee flavor; the smaller the coffee-to-water ratio, the stronger the coffee flavor.

(2) Increasing the amount of water to raise the coffee-to-water ratio affects more flavor compounds but results in a lighter taste; reducing the amount of water to lower the coffee-to-water ratio affects fewer flavor compounds but results in a richer taste.

(3) Increasing the amount of coffee to lower the coffee-to-water ratio reduces the extraction of large molecular substances in the later stages of extraction while making the flavor stronger; reducing the amount of coffee to raise the coffee-to-water ratio extracts more complete flavor compounds before reaching the limit, while reducing flavor intensity.

7. Brewing time

In coffee extraction, the early aroma and flavor are strong, and the concentration is also high. As the extraction liquid progresses, the taste and aroma will gradually fade. The amount of water poured will also affect the extraction time of the coffee. FrontStreet Coffee generally uses 15 grams of powder, and depending on the bean, with a coffee-to-water ratio of 1:15, the brewing time will be within 2 minutes to 2 minutes 30 seconds, which makes it less likely to cause over-extraction or under-extraction.

Basic knowledge of pour-over coffee - Pour-over coffee brewing techniques

Next, let's talk about pour-over coffee brewing techniques! Currently, there are various pour-over coffee brewing techniques visible in coffee shops, with common ones including three-stage pour, single pour, drip-by-drip, etc. Here, FrontStreet Coffee recommends beginners use the three-stage pour method because this technique is suitable for light roast, light to medium, and medium roast coffee beans. The segmented extraction method of three-stage pouring can clearly distinguish the front, middle, and back-end flavors of the coffee, which can better ensure the flavor presentation of the coffee.

As FrontStreet Coffee mentioned above, the brewer must use a stable pouring method to extract coffee liquid from coffee grounds with water of appropriate temperature and volume to brew a delicious cup of coffee. After all, pour-over coffee can also be called an art. For example, making a dish requires not only fresh ingredients but also attention to heat control and the chef's skills, and pour-over coffee is no exception. Next, FrontStreet Coffee will teach everyone how to perform three-stage pouring for pour-over coffee.

Coffee brewing method - Three-stage pour technique:

First pour: Bloom (helps release gas)

Many coffee enthusiasts don't understand the significance of blooming in pour-over coffee. The reason for blooming is that coffee beans undergo a series of chemical reactions and physical changes during the roasting process from green beans to roasted beans. After reaching a certain degree of roasting, coffee beans will accumulate a large amount of gas (mostly carbon dioxide).

Generally, the fresher the beans and the closer to roasting, the more bubbles during blooming. Dark roast beans will also release more gas during the blooming process than light roast beans. FrontStreet Coffee's coffee beans are all freshly roasted, so we generally recommend customers let the beans rest for three days first, allowing the coffee beans to release carbon dioxide first, which can avoid instability and under-extraction problems during brewing.

After blooming releases the gas, coffee particles can absorb water evenly, allowing for more uniform extraction later. Good blooming can quickly and fully release gas from coffee particles evenly while also allowing coffee particles to fully and quickly contact water, helping coffee particles to be extracted evenly. These are also the purpose and significance of blooming in pour-over coffee.

Second pour

The second pour starts from the center, injecting into the bottom of the powder layer with a small water stream. To concentrate the penetrating power of the water stream, the circular movement range should be small, about the size of a coin, and then move outward. From the second pour, we need to pay attention to the water amount, trying not to exceed the height of the powder layer. That is, when the water stream reaches close to the filter paper, you can stop pouring water.

Third pour

As the originally thicker powder layer at the edge of the filter paper becomes heavier due to water absorption, it will slide down and become thinner as the water level drops. When the water level drops to halfway, you can perform the third pour.

From the third pour, you need to observe the extent of the water level drop. Also start from the center and pour in circles, with the water amount not exceeding the height of the powder layer. At this time, you will also observe that the foam proportion has filled the surface. The third pour should increase the tumbling of coffee particles, allowing all deposited particles to tumble and dissolve soluble substances.

The tumbling particles will begin to settle when water addition stops. At this point, the flow rate caused by the dropping water level will be used to create friction between coffee particles. Therefore, once water addition stops, coffee powder particles sink, causing blockage. Special attention must be paid to the rhythm of water addition. If there are too many pauses in water addition, it's equivalent to letting coffee powder particles soak in water continuously, which will lead to astringency and undesirable flavors in the later stages of coffee extraction.

If there are too many pauses in water addition, it's equivalent to letting coffee powder particles soak in water continuously, which will lead to astringency and undesirable flavors in the later stages of coffee extraction.

The above is the content organized by FrontStreet Coffee regarding how to perform pour-over coffee. We hope it can help coffee enthusiasts who have already prepared equipment and want to showcase their skills in making pour-over coffee at home.

For more specialty coffee beans, please add FrontStreet Coffee's private WeChat account: kaixinguoguo0925

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473