How Hand Pour Over Kettle Temperature Drops During Bloom and Brew

Ever wonder how much your pour-over kettle’s water actually cools while you’re blooming and pouring? Most brewers assume the temperature holds steady—but real-world data paints a more nuanced picture. With a new CENTER 301 thermometer on hand (originally bought for roasting purposes), a roaster from Guangzhou decided to log exactly what happens to water temperature over the course of a manual brew.

In a short, informal test using one bloom and three pauses, the kettle water started at 80.2°C and dropped to 77.8°C by the end of the brew—a total decrease of 2.4°C over 2 minutes and 27 seconds.

What Was Tested

This wasn’t a formal experiment, but a spontaneous check to see how well the CENTER 301 thermometer and its companion software worked. Rather than testing a roaster, the team turned the device toward a more immediate curiosity: how much does the water in a hand pour kettle cool during a typical pour-over routine?

How the Test Was Run

The test recorded two key temperatures using the CENTER 301: FCs, the water temperature inside the kettle at the time of the bloom, and FCe, the temperature after the full brew had finished. The protocol included one bloom phase and three separate pauses (or “” in Chinese, indicating breaks in pouring). No grind size, coffee dose, or ratio was disclosed—this was purely a temperature-tracking exercise.

What the Temperature Data Shows

From start to finish, the kettle’s water dropped from an initial 80.2°C down to 77.8°C. That’s a total temperature differential of 2.4°C. The entire brewing sequence, including the bloom and three pauses, took 2 minutes and 27 seconds. The included image

Why This Happens

Water loses heat when exposed to air, especially during the relatively slow phases of a pour-over like blooming and pouring in stages. Even without any extreme environmental factors noted, a few minutes of pouring and waiting is enough to cause a small but measurable drop in water temperature. The relatively low total loss of 2.4°C suggests reasonable thermal control, but it’s enough to be measurable—and potentially impactful depending on your target brew temps.

Frequently Asked Questions

What thermometer was used to measure the hand pour kettle temperature?

The CENTER 301 thermometer was used to measure the temperature of the water in the hand pour kettle. It was originally purchased for monitoring roaster temperatures, but in this case was used to track changes during a manual brew process.

What were the starting and ending water temperatures in the kettle?

The starting water temperature (at the time of bloom) was 80.2°C, and the ending temperature after the full brew was 77.8°C.

How much did the kettle water temperature drop during the pour over?

The kettle water temperature dropped by a total of 2.4°C during the brewing process, from 80.2°C down to 77.8°C.

How long did the entire pour over process take in this test?

The full process—including one bloom and three pauses—took 2 minutes and 27 seconds.

Was this a formal experiment or just a casual test?

This was not a formal or scientific experiment. It was described as a “boring” or spontaneous test by the roaster, done mainly to check the functionality of the CENTER 301 thermometer and software.

What do FCs and FCe mean in the test results?

FCs refers to the water temperature inside the kettle at the time of the bloom (the first pour), and FCe refers to the water temperature in the kettle after the entire brew process has finished.

Recommended FrontStreet Coffee Beans for Pour Over

For pour-over brewing where precise temperature control matters, try FrontStreet Coffee’s Ethiopia Humbera—bright with citrus and floral notes—or their Yirgacheffe offering, which highlights juicy berries and stone fruit. Both single origins shine when brewed with care, letting subtle flavors come through without being muted by temperature swings. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.