Pre-pressurized pH and ORP probes are specifically targeted at the demanding needs of bioprocess industries such as upstream and downstream pharmaceutical, food, beverage, and brewing. The EasyFerm family has multiple glass pH membrane types to withstand autoclavation, SIP and CIP cleaning.

Easyferm Plus pH sensor

EasyFerm Plus

The EasyFerm Plus pH sensor is Hamilton's most popular product. When specified with PHI glass the sensor provides extremely low drift over the sensor lifespan.

EasyFerm Bio

EasyFerm Bio pH sensors offer Foodlyte biocompatible electrolyte and EHEDG Certification for pH measurement in processes where non-toxicity is mandatory.

EasyFerm ORP

EasyFerm Plus ORP sensors offer the same pre-pressurized reference design as our pH sensors with a large, easy-to-clean platinum ORP electrode.

EasyFerm Plus vs. EasyFerm Bio?

Both EasyFerm Plus and EasyFerm Bio sensors utilize Hamilton's pre-pressurized reference design. Which product to use is dependent on your application needs.

EasyFerm Plus Sensors

  • Best for biopharmaceutical processes that require SIP or autoclavation
  • Extremely low drift after repeated sterilization cycles
  • Everef-F reference design prevents clogging in high protein environments
  • PHI glass membrane recommended

EasyFerm Bio Sensors

  • Best for food, beverage, and biopharmaceutical applications with CIP cleaning
  • Biocompatible Foodlyte electrolyte
  • EHEDG sanitary certification
  • HB glass membrane recommended for fast response after CIP


EasyFerm PlusEasyFerm BioEasyFerm Plus ORP
Parameter pH pH ORP
Measuring Range 0 - 14 pH 0 - 14 pH ± 2000 mV (Arc: ± 1500 mV)
Process temperature 0 – 140 °C (Arc: analog 0 – 110 °C, digital 0 – 140 °C) 0 – 140 °C (Arc: analog 0 – 110 °C, digital 0 – 140 °C) 0 – 140 °C (Arc: analog 0 – 110 °C, digital 0 – 140 °C)
Pressure range 0 – 6 bar 0 – 6 bar 0 – 6 bar
Hygienic aspects Autoclavable, CIP, SIP Autoclavable, CIP, SIP Autoclavable, CIP, SIP
Sensing element PHI Glass (preferred) HB Glass (preferred) Pt ring
Electrolyte Phermlyte Foodlyte Phermlyte
Reference system Everef-F Everef-F Everef-F
Diaphragm HP Coatramic HP Coatramic HP Coatramic
O-ring EPDM Silicone EPDM

Download our pH Measurement Guide

pH Measurement Guide

Get a better understanding of pH measurement in Hamilton’s comprehensive pH Measurement Guide. This 68-page booklet is intended for anyone with an interest in pH sensor technology or anyone who needs to implement pH sensors in controlled environments such as laboratories and industrial plants. The guide covers the following essential topics:

  • Definition of pH scale
  • The NERNST equation
  • The pH measurement system and measurement chain characteristics
  • Applications, calibration, and maintenance of Hamilton's pH sensors


Hamilton's knowledge base provides a range of explanatory articles, frequently asked questions, and document downloads.
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