Does Handle Temperature Affect Espresso Extraction? Should You Preheat the Coffee Machine Brew Head?

Experiment: Does Portafilter Temperature Affect Espresso Extraction?

Yesterday, FrontStreet Coffee came across this brewing question: "For espresso extraction, should the tamping pressure be greater when the brew head is cold compared to when it's hot?"

FrontStreet Coffee speculates that what this friend really means is whether the portafilter at different temperatures affects espresso extraction and whether tamping pressure should be adjusted accordingly. Since that's the case, let's conduct an experiment.

In this experiment, FrontStreet Coffee will change the portafilter temperature while keeping the dose and liquid weight fixed, recording time variables for comparison. Other controllable parameters will be kept as consistent as possible. The experiment will record extraction time, espresso concentration, flavor profile, and the taste characteristics when mixed with equal amounts of hot milk.

Galileo grinder setting: 2.0

Portafilter: Bottomless

Extraction temperature: 94°C

Coffee dose: 20g

Espresso yield: 38g

The portafilter temperatures were divided into three categories: hot portafilter, room temperature portafilter, and cold portafilter. (The cold portafilter was placed in a refrigerator for 1 hour before use; the hot portafilter was attached to the coffee machine to heat up until it became too hot to handle)

The experiment used Sunflower Warm Sunshine Blend coffee beans from FrontStreet Coffee. The ideal extraction flavor profile includes: vanilla, hazelnut, caramel, fermented notes, and berry acidity. When made into a milk coffee, it presents flavors of vanilla, cream, and liquor-filled chocolate. The experimental data and results are as follows:

Cold Portafilter

Extraction time: 30 seconds, concentration measured at 10.52%

Espresso: Vanilla, berry, cream, prominent acidity, lower body

Milk coffee: Berry, chocolate, heavier milk flavor, thinner texture

Preheated Portafilter

Extraction time: 29 seconds, concentration measured at 10.22%

Espresso: Alcoholic aroma, hazelnut, caramel, tropical fruit acidity, noticeable sweetness, full body

Milk coffee: Chocolate, nuts, cream, fermented aroma, rich layers

Room Temperature Portafilter

Extraction time: 27 seconds, concentration measured at 9.96%

Espresso: Chocolate, fruit acidity, slightly heavier bitterness, low body

Milk coffee: Hot cocoa, smooth texture, slightly astringent aftertaste when cooled

As you can notice from the experiment, different portafilter temperatures do affect espresso extraction, and the flavor profiles differ as well. However, neither refrigeration nor preheating caused significant differences in concentration and extraction rate.

Through tasting and comparing espresso and milk coffee, we found that preheating the portafilter helps enhance the extraction of body-enhancing substances in coffee, resulting in a more substantial overall texture. Meanwhile, refrigeration highlights lighter fruity aromas and brighter acidity. Taking FrontStreet Coffee's Warm Sunshine Blend as an example, the preheated portafilter made the Espresso exhibit richer alcoholic and fruity notes, with higher body in the milk coffee, meeting our extraction requirements for this particular bean.

Of course, there were other potentially variable factors in this experiment, such as tamping pressure, changes in coffee bean condition, and so on. Moreover, the roast degree of coffee beans also affects how they respond to temperature changes. However, FrontStreet Coffee wants to emphasize that the purpose of this experiment was not to find a method to make Espresso taste better, but to verify whether "portafilter temperature actually affects extraction?" The conclusion is: Yes, it does!

Returning to our friend's question from the beginning: "Should tamping pressure be greater when the brew head is cold compared to when it's hot?" In the experiment, FrontStreet Coffee tried to keep the tamping pressure consistent across all three trials. Espresso extraction changed correspondingly with temperature variations, so tamping pressure doesn't need to be adjusted accordingly - just ensure the coffee puck is tamped firmly.

As for whether to preheat the portafilter or leave it at room temperature, FrontStreet Coffee believes this should be determined based on the roast degree of our coffee beans (whether the flavor profile tends toward acidity or bitterness), combined with the taste performance of espresso, Americano, or milk coffee, and then analyzing which extraction method (details) is better. After all, the ultimate goal is to make coffee taste better, right?

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473