Glass Spreaders

The standard L-spreader has a short angled tip that lies flat on the agar surface during rotation, and is the most widely used for general bacterial plating. T-spreaders have a longer horizontal surface and can cover a larger plate area per stroke, useful for high-throughput plating.

Use borosilicate glass 3.3 spreaders for thermal resistance, chemical inertness, and autoclavability. Borosilicate spreaders withstand repeated alcohol flaming and autoclave sterilisation at 121 degrees Celsius without warping or cracking. All SmartLabs glass spreaders are made from borosilicate glass.

A handle length of 150 to 200 mm is typical for standard 90 mm Petri dishes, keeping your hand above the agar while spreading. Shorter 100 mm handles are available for smaller plates or work inside laminar flow cabinets where reach is limited.

Glass spreaders can be autoclaved before use or flame-sterilised at the bench using 70 to 95 percent ethanol or isopropanol. When flaming, dip the tip in alcohol, ignite briefly, and allow the flame to burn out completely before cooling on the agar edge. Never return a hot spreader to the alcohol container. Autoclaving is the safest approach for critical sterility work.

A glass spreader evenly distributes a liquid inoculum across the surface of an agar plate using the spread plate method, producing well-separated colonies for identification, enumeration, antibiotic sensitivity testing, and isolation of pure cultures.

Dip the tip into 70 to 95 percent ethanol or isopropanol, briefly ignite it, allow the flame to burn out completely, then cool the tip on the inner edge of the agar before spreading. Never return a burning or hot spreader to the alcohol container as this can ignite the alcohol reservoir.

Yes. Borosilicate glass spreaders can be autoclaved at 121 degrees Celsius for 15 to 20 minutes. Place them in a sealed glass or stainless steel container to maintain sterility after the cycle. Autoclaving a full set before a plating session is preferred for critical sterility work.

An L-spreader has a short angled spreading tip perpendicular to the handle, most common for standard agar plates and single-hand rotation spreading. A T-spreader has a longer horizontal bar covering more area per stroke, useful for high-throughput or large-plate applications. Both work on the same principle.

Soak in 10 percent bleach or laboratory disinfectant for at least 30 minutes, rinse with water, wash with laboratory detergent, rinse with distilled water, and allow to dry completely before autoclaving. Inspect the tip for chips or cracks before reuse, as damaged spreaders can scratch the agar surface.