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Ruby Pro-Sear Grills: How Direct-Flame Searing Works

Sunstone Metal Products · June 10, 2026

The Science Behind Direct-Flame Searing

To understand why the Ruby Pro-Sear series represents such a significant advancement in outdoor cooking technology, it helps to understand the fundamental physics of heat transfer. There are three mechanisms by which heat moves from a source to food: conduction (direct contact), convection (hot air movement), and radiation (electromagnetic energy transfer).

Direct-flame sear on a Ruby grill
Direct flame under the sear grate is why a Ruby lays down a crust before the center overcooks.

Many gas grills cook mostly with hot air. The burners heat the air under the hood, and that air cooks the food. It works, but hot air alone is slow to build a hard crust. Food can dry out while you wait for color.

30" Ruby 3 Burner Pro-Sear Grill - RUBY3B
30" Ruby 3 Burner Pro-Sear Grill - RUBY3B

A Ruby Pro-Sear takes the direct route. Fabricated stainless I-burners sit under the cooking surface, each up to 20,000 BTU. Their flame heats the grate from below. With the sear grate insert in place, the cooking surface reaches up to 800°F. That is steakhouse heat on a backyard grill.

The Maillard Reaction: The Key to Great Flavor

The reason extreme surface temperatures matter so much in cooking comes down to a chemical reaction called the Maillard reaction. Named after French chemist Louis-Camille Maillard, who first described it in 1912, this reaction occurs when amino acids and reducing sugars are exposed to high heat (above approximately 280°F). The reaction produces hundreds of different flavor compounds that create the complex, savory flavors we associate with properly seared meat.

The Maillard reaction is what creates the brown crust on a perfectly seared steak, the golden exterior of a roasted chicken, and the caramelized surface of a grilled vegetable. Without sufficient surface temperature, this reaction doesn't occur, and food tastes flat and one-dimensional by comparison.

On the Pro-Sear grate, high direct heat starts that browning fast. The crust forms before the center has time to overcook. You get a more even doneness from edge to center.

Ruby Series Models: Finding Your Perfect Match

Steaks searing on a 36-inch Ruby 4-Burner Pro-Sear grill
Step up to the 36" Ruby 4-Burner (RUBY4B) when the guest list outgrows 30 inches.
3030" Ruby 3-Burner Pro-Sear30" cut-out · 540 sq in · up to 60,000 BTU3636" Ruby 4-Burner Pro-Sear36" cut-out · 720 sq in · up to 80,000 BTU

The Ruby series is available in multiple configurations to suit different outdoor kitchen sizes and cooking needs:

Ruby 3-Burner: The entry point to the Ruby series, perfect for smaller outdoor kitchens or households that primarily cook for 2-4 people. Despite its compact size, the 3-burner Ruby delivers the same direct-flame Pro-Sear searing as the larger models, with up to 60,000 BTU.

Ruby 4-Burner: The most popular configuration in the Ruby series, offering the ideal balance of cooking capacity and footprint. The 4-burner model can comfortably handle meals for 6-8 people. The w/IR version (RUBY4BIR) adds an infrared rear burner for rotisserie cooking.

Ruby 5-Burner: The flagship of the Ruby series, designed for serious outdoor cooks and frequent entertainers. The 5-burner configuration provides ample cooking space for large gatherings while offering the flexibility to create multiple distinct temperature zones simultaneously.

Ruby Grill Warranty: Industry-Leading Coverage

Sunstone stands behind the Ruby series with one of the most comprehensive warranties in the outdoor cooking industry.

This warranty coverage reflects the quality of materials and construction that goes into every Ruby grill. Sunstone's manufacturing standards are among the highest in the industry, with each grill undergoing rigorous quality control testing before leaving the factory.

Cooking Tips for Pro-Sear Grills

Getting the most from your Ruby Pro-Sear grill comes down to a few simple habits. Here are the key techniques to master:

Preheat thoroughly: Light the I-burners and close the hood. Give the sear grate insert time to come fully up to temperature before food goes on.

Keep the grill clean: Brush the grates after each cook. A clean grate sears better and keeps grease flare-ups down.

Use the two-zone method: For thicker cuts, sear on the Pro-Sear grate, then move the food to a burner turned lower, or turn one burner off to finish with indirect heat.

Embrace the speed: High direct heat builds a crust fast. Watch your first steak closely and set your timing from there.

Save the back burner for the rotisserie: On w/IR models, the infrared rear burner (up to 15,000 BTU) is for rotisserie cooking. Searing happens on the Pro-Sear grate.

See our warranty page for coverage details.

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