Gerber WB 436-D Universal Water Bath for Butyrometry

Overview

The Gerber WB 436-D is a precision-engineered universal water bath designed specifically to support standardized fat extraction and quantification procedures in dairy quality control laboratories—most notably the Gerber method (ISO 1211:2010) and Mojonnier method (AOAC 920.119) for milk and cream fat determination. Operating on resistive heating with forced convection via an integrated circulation pump, the WB 436-D maintains thermally uniform conditions across its 16-liter stainless-steel bath chamber, ensuring reproducible incubation of fat-extraction tubes under strictly controlled time–temperature protocols. Its dual-stage overheat protection system—comprising both electronic thermostat redundancy and independent mechanical thermal cutoff—guarantees operational safety even during unattended operation or accidental dry-run scenarios. Unlike general-purpose water baths, the WB 436-D integrates ergonomic design features optimized for high-throughput butyrometric workflows, including front-accessible tube rack mounting points and compatibility with industry-standard Gerber-type glassware.

Key Features

• Stainless steel double-walled construction with seamless inner chamber for corrosion resistance and long-term fluid integrity
• Microprocessor-controlled PID temperature regulation with 4-digit LED display and ±0.3 °C stability at 37 °C (per ISO/IEC 17025 calibration traceability)
• Dual-mode circulation: internal recirculation for bath homogeneity + external port for auxiliary loop integration (e.g., inline chillers or secondary reactors)
• Dry-run safe operation enabled by embedded temperature sensors monitoring both heater surface and bath fluid—automatically de-energizing power if ambient air detection occurs
• Programmable digital timer (1–99 minutes) with audible end-of-cycle alert and auto-hold function
• Front-panel accessible mounting interface compatible with optional Gerber-certified tube racks: 3717 (36-position Gerber tube holder), 3718 (10-position Mojonnier tube holder), 3727 (flat perforated partition plate), and 3737 (two-tier 99-position rack)

Sample Compatibility & Compliance

The WB 436-D accommodates standard Gerber fat-testing glassware (e.g., 10 mL and 11 mL graduated butyrometers) as well as Mojonnier ether-extraction flasks (50 mL and 100 mL). Its bath geometry and temperature uniformity profile comply with the spatial and thermal requirements specified in ISO 1211:2010 (Milk — Determination of fat content — Gerber gravimetric method) and AOAC Official Method 920.119. The unit meets EN 61000-6-3 (EMC emission limits) and EN 61000-6-2 (immunity), and its electrical safety conforms to IEC 61010-1:2010 for laboratory equipment. While not intrinsically GLP/GMP validated out-of-box, the WB 436-D supports IQ/OQ documentation packages and is routinely deployed in FDA-regulated dairy testing facilities where audit-ready temperature logging (via optional RS232/USB interface) and 21 CFR Part 11–compliant software integration are implemented.

Software & Data Management

The WB 436-D operates as a standalone instrument with embedded firmware; no proprietary software is required for basic operation. However, optional serial (RS232) or USB connectivity enables integration with third-party laboratory information management systems (LIMS) or electronic lab notebooks (ELN). When paired with Gerber’s optional LogSoft™ data acquisition module, users can generate timestamped temperature/time logs compliant with ALCOA+ principles (Attributable, Legible, Contemporaneous, Original, Accurate), supporting full traceability for regulatory submissions. All configuration parameters—including setpoint, timer value, and calibration offsets—are password-protected and retain settings after power cycle.

Applications

• Routine fat quantification in raw milk, pasteurized milk, cream, and whey using Gerber or Mojonnier methodology
• Standardized incubation of lipid-solubilization reagents (sulfuric acid, amyl alcohol, diethyl ether) prior to centrifugation
• Controlled warming of viscosity reference standards in dairy rheology workflows
• Pre-heating of culture media or enzymatic assay buffers requiring stable sub-boiling temperatures
• Supporting ISO 5530-1 (milk fat determination by infrared) as a complementary thermal conditioning step

FAQ

Can the WB 436-D be used with oil instead of water?
Yes—the bath chamber is chemically resistant to mineral oils and silicone-based heat-transfer fluids up to 99 °C; however, oil use requires manual verification of fluid level and periodic replacement due to oxidation risk.
Is external temperature calibration supported?
Yes—calibration offset adjustment is accessible via service mode, and NIST-traceable PT100 probe input is available as a factory-configurable option.
Does the unit meet CE marking requirements for EU laboratory use?
Yes—certified to CE directives 2014/30/EU (EMC), 2014/35/EU (LVD), and 2012/19/EU (WEEE), with Declaration of Conformity supplied with each unit.
What maintenance is required for long-term accuracy?
Monthly inspection of circulation pump impeller, biannual descaling with citric acid solution (if using tap water), and annual verification of thermal cutoff response per IEC 61010-1 Annex H.
Can multiple WB 436-D units be synchronized for parallel testing?
Not natively—but external PLC control via dry-contact relay outputs (optional accessory) allows coordinated start/stop sequencing across up to eight units.