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Hydro-Thermal has 80 years of steam expertise and the SilverLine is our latest innovation.

Who We Are

Steam Innovation in your Kitchen

Steam has been used to safely process foods and beverages for more than half of a century. Hydro-Thermal has 80 years of steam expertise and the SilverLine is our latest innovation.

The SilverLine is a streamlined, self-contained, polished stainless steel system designed to cook recipes exactly as specified, replacing heat exchangers and kettles.

Our patented food and beverage processing system mixes steam and liquid foods and beverages completely while delivering precise and consistent temperature control, instantaneous heating and no scaling or fouling of the product.

A History of Steam Innovation

Hydro-Thermal engineering drawing


Hydro-Thermal traces its roots back to 1927, when inventors John White and Roy Miller patented heating equipment using steam to precisely control water temperature. The device was “direct in action,“ extended the service life and used a “valve seat with a sliding closure member." These components continue as a foundation for Hydro-Thermal technology.


In the early 1930’s, manufacturing industrialist Harry Schauer brought this technology to paper mills in Wisconsin. Through collaboration with chief engineers from Kimberly-Clark, they applied the equipment to heat byproducts for cooking in digesters, recaustization, atomizing, and providing accurately controlled hot water. The heater became the heat catalyst in these chemical reactions and became known as the Hydroheater™, which was first manufactured in 1934.

Hydroheater valves from 1930



The Zaiser family purchased the business in 1964 and renamed it Hydro-Thermal Corporation. Donald Zaiser operated the company at its Wauwatosa, Wisconsin location on 70th and State Street. Companies like Corn Products Company, Cerestar, ADM, Grain Processing, and Cargill used the Hydroheater for integrated corn based sugar production.


Man with two Hydroheaters

Gary Zaiser began the second generation of ownership in 1979. With his expertise, the company expanded applications to grain based ethanol at Andersons, Badger State Ethanol, Flint River and VeraSun, and the chemical industry at Ashland Chemical, EI DuPont, PCS Phosphates and PPG Industries. Hydro-Thermal expanded their facility and moved to Waukesha, Wisconsin and also grew in knowledge through several university partnerships to generate fundamental research in steam heating.

Awards & Achievements

Hydro-Thermal recently celebrated 80 years of steam innovation.

Jim Zaiser, who represents the third generation, is leading the company’s product diversification, advanced two-phase flow realization, international expansion, and system integration. The company has continued its application to the traditional industries as well as installations in food processing, mining and petroleum.

Today the company has more than a dozen active patents and registration in multiple foreign countries. It manages its business process though an integrated ISO 9001 quality procedure. A test lab on-site allows engineers, researchers and academia to completely understand and develop new innovative and value-added processes. The company continues to invest in people, hiring smart and aspiring engineers and investing in the health and wellness of all employees.

Man with Hydro-Thermal Hydroheater
Jim and Gary Zaiser at Hydro-Thermal headquarters with Hydroheater
  • The Sanitary Hydroheater was created in 1991 and received 3A certification so the company could pursue food, beverage and pharmaceutical applications.

  • By 1992, Hydro-Thermal was partnering with key OEMs and system integrators specializing in large-scale food industry projects, ranging from CIP to full kitchens.

  • In 2010, Food Manufacturing Magazine gave the Smart Sourcing Award to Creekstone Farms for their use of Hydroheaters in their central hot water system.

  • McDonald’s USA gave the 2011 Quality Award to our customer, a supplier to the leading global food service retailer, who uses Infuze heaters (the heart of SilverLine) for an immersion cooking process.

  • In 2014 the Wisconsin Innovation Quotient Award (I.Q.) was given to Hydro-Thermal for the Smart Cooking System, the name the SilverLine system had while in development. This award is given to those companies who develop innovative or unique products or services.

Hydro-Thermal's wall dedicated to its many awards and achievements

Manufacturing Best Practices

A machinist producing a Hydro-Thermal Hydroheater

Engineering Innovation

Hydro-Thermal has an 80-year heritage of steam innovation and knowledge.

Hydro-Thermal Engineering Innovation »

Many organizations provide guidelines to ensure that food equipment is hygienically made for commercial production. SilverLine defines a new benchmark and provides a direction for ultra hygienic food equipment in the future.

Manufacturing Best Practices »

SilverLine food processing equipment is hygienically designed
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