HB-L2 Roaster’s PT100 Probe: German Pt100 Sensor Specs & Use

If you’ve ever tried to dial in roast profiles on an HB-L2 and wondered how accurate your temperature readings really are, you’re not alone. One key piece of the puzzle is the pt100 temperature probe—this small sensor has a big impact on how reliably you track bean and air temperatures throughout the roast.

The HB-L2 uses a German Heraeus-imported Pt100 temperature probe with an M6*60 threaded body and 1.5-meter cable. This sensor measures both bean and hot air temperatures, and it’s built to maintain accuracy under roasting conditions.

What Is the HB-L2 Pt100 Probe?

The HB-L2 pt100 probe is a temperature-sensing device designed specifically for measuring bean and air temperatures during coffee roasting. It connects to the roaster’s control system to provide live temperature data, essential for tracking the roast progression and hitting desired development markers. The probe features a durable design with food-safe materials and high-temperature-resistant wiring.

Key Specifications of the Probe

The probe comes with the following technical specifications:

• Type: K-type PT100
• Thread Size: M6*60
• Cable Length: 1.5 meters
• Temperature Range: Approximately -70°C to 450°C
• Use Case: Specifically for HB-L2 coffee roasters to measure both bean temperature and hot air temperature

Build Quality and Materials

The sensing element inside the probe is a high-grade Pt100 platinum resistor from Heraeus, a German company with over 155 years of expertise in material science. The metal part of the probe tip is made from food-grade 304 stainless steel to ensure it doesn’t contaminate the coffee. The cable is a two-wire system using high-temperature silver-plated wiring with a PTFE (Teflon) outer sheath. This construction allows the cable to resist heat up to 180°C, as well as corrosion, moisture, and acid—ensuring stable signal transmission even in demanding roasting environments.

About the Heraeus Pt100 Sensor

Heraeus Holding, founded in 1851 and headquartered in Hanau, Germany, is a global leader in precious metals and advanced materials. Their sensors—including the Pt100 used in the HB-L2 probe—are widely regarded in industrial applications for their precision and reliability. Heraeus operates 25 R&D centers globally, employs over 12,300 people, and serves multiple high-tech sectors, including medical technology, telecommunications, and specialty sensing.

You can find more about Heraeus at their official website: http://www.heraeus.com/

How to Test the Pt100 Probe

To confirm the functionality and consistency of your Pt100 probe, you can perform a simple resistance test using multiple probes under controlled conditions:

• Prepare a thermos or insulated cup with a mixture of ice and water (allow it to stabilize at around 0°C for 2–5 minutes).
• At 0°C, the correct resistance of a Pt100 sensor should measure 100 ohms.
• Then, gradually heat the water and monitor the resistance change.
• Using a multimeter, check the resistance at various temperatures. For every 1°C increase, the resistance should rise by approximately 0.385 ohms.
• Compare multiple probes—if their resistance values change consistently and within a tight range, they are likely accurate and well-matched.

Testing with two to five probes simultaneously in the same thermal environment will help you identify any units with higher variance or drift.

Frequently Asked Questions

What is a Pt100 sensor and why does my HB-L2 roaster use one?

A Pt100 sensor is a platinum resistance thermometer that measures temperature based on the change in electrical resistance of platinum at different temperatures. The “100” means it has a resistance of 100 ohms at 0°C. The HB-L2 uses this type of sensor for accurate, reliable temperature readings of both bean mass and hot air during roasting.

What temperature range can the HB-L2’s Pt100 probe handle?

The probe can measure temperatures from approximately -70°C to 450°C, covering the full range of coffee roasting from warm-up to first crack and beyond.

What does M6*60 and 1.5m cable mean for the probe?

M6*60 refers to the probe’s threaded connection size (6mm diameter, 60mm length), which attaches it securely to the roaster. The 1.5m cable length allows flexible placement of the probe’s connection point near the control unit while keeping the sensor in the bean mass or airflow path.

Why is the Heraeus Pt100 sensor considered high quality?

Heraeus is a German manufacturer with over a century and a half of experience in precision materials. Their Pt100 elements are known for stability, accuracy, and durability under industrial conditions, making them a trusted component in professional coffee roasting equipment.

How can I test if my Pt100 probe is working correctly?

You can test the probe by placing it in an ice-water bath (0°C) and verifying it reads 100 ohms. Then heat the water and check that resistance increases by roughly 0.385 ohms per 1°C. Comparing multiple probes under the same conditions helps spot inconsistencies.

Recommended FrontStreet Beans for Roast Profiling with Pt100

For roasters using the HB-L2 with a Pt100 probe to fine-tune their profiles, try FrontStreet Coffee’s Ethiopia Humbera for bright citrus and floral notes, Yirgacheffe for juicy berry and stone fruit, or Brazil Queen Manor for chocolatey nutty balance. These single origins highlight how precise temperature control affects sweetness, acidity, and development. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.