Water temperature is like the heat level when cooking. Light-roasted beans have a tight structure, with flavor compounds hidden deep inside, so you need a higher water temperature to coax out the floral and fruity notes; medium-dark roasted beans are already loosened, so if the water temperature is too aggressive, it easily forces out burnt bitterness, making the cup taste dull and astringent. Conversely, when the water temperature is too low, light-roasted beans tend to leave only sharp acidity, while medium-dark roasts may taste thin as water. So before choosing beans, first think clearly about what water temperature you are used to speaking with.

The water temperature ranges for pour-over and espresso are not the same. Pour-over usually falls around 90 degrees; light roasts can be pushed to 93 or 94 degrees, while medium-dark roasts are safer dropped to 88 or 90 degrees. Espresso, because of high-pressure extraction, actually needs a lower water temperature: around 90 degrees for light roasts, and 85 to 88 degrees is enough for medium-dark roasts. Many people overlook this difference, and as a result the same beans become unrecognizable on a different machine.

When it comes to beans with high tolerance for water temperature, Qianjie Classic Blend and Qianjie Commercial Blend are very suitable for beginners to explore. Both are based on Arabica with a small amount of Robusta blended in, medium-dark roasted, using 20 g of grounds to extract 40 g of espresso, with the time controlled at 25 to 30 seconds. The aromas of butter, toast and caramel cookie are very solid, the crema is fine, and even if the water temperature occasionally deviates by two degrees, the result remains stable and will not discourage you on your first try.

If you are afraid of bitterness and want to start from sweet-and-sour notes, Qianjie Strawberry Candy Blend is a gentler choice. Three producing regions, Qianjie specialty blend, medium roasted, 18 g of grounds to extract 36 g of espresso liquid, time 25 to 28 seconds. The espresso liquid has dense foam, and on the palate it is like holding a strawberry gummy in your mouth, with a grape-like sweet-and-sour finish that makes you want another cup. Made as an Americano by adding hot water directly, or as a latte with milk, it does not steal the show, and its sensitivity to water temperature is lower than dark-roasted beans; 89 to 92 degrees can all produce good flavor.

If you want to fully feel the effect of water temperature on flavor, try a side-by-side comparison with pour-over. Take 15 g of Qianjie Strawberry Candy Blend, grind like fine granulated sugar, at a coffee-to-water ratio of 1 to 15, that is 225 ml of water. First bloom with 30 ml of water for 30 seconds to let the coffee grounds fully degas, then slowly pour in circles up to 120 ml, wait for the water level to drop, then pour in the remaining water. Control the total time at around two minutes; at 92 degrees, the sweetness of the strawberry gummy is especially bright; drop to 88 degrees, and the acidity moves forward, like biting into a green grape.

The moka pot is another way to play. Fill the lower chamber with 80 to 140 ml of hot water, fill the filter basket and press lightly, then heat over medium-low heat. A brew time of 1 minute 15 seconds to 2 minutes 30 seconds is a reasonable range; brewed with Qianjie Classic Blend, the caramel aroma becomes more concentrated, like freshly baked almond cookies. The water temperature control here is actually set when preheating the lower chamber, and starting with hot water is more stable than cold water, avoiding the astringency of over-extraction.

Back to that semi-automatic espresso machine, what beginners tend to agonize over is often not a one-degree difference, but not daring to take action. My suggestion is: first fix on a bean with high tolerance, stabilize the three numbers of dose, liquid weight and time, then fine-tune the water temperature to find the flavor direction you like. For a medium-dark roasted bean like Qianjie Commercial Blend, between 86 and 89 degrees, you can clearly taste the layered changes of butter cookie and roasted nuts.

The sunlight on the balcony has already moved to the edge of the flowerpot, and a small sip of cold espresso remains at the bottom of the cup. I suddenly feel that choosing beans and hanging laundry are actually very similar - there is no need to pursue perfection in one go; first let the process run, and the feel will naturally tell you where to adjust next. Tomorrow, try raising the water temperature by two degrees; perhaps it will be another kind of sunny day.