Culture Vial/Tube, Clear Glass

Quick Answer: The Culture Vial/Tube, Clear Glass is a transparent glass vessel for growing microbial and other cultures. A clear glass culture tube lets students watch what happens inside, from cloudy growth in broth to colour changes and gas bubbles in biochemical tests.

Seeing Growth Through Clear Glass

Much of routine microbiology is read by eye through the tube wall. A broth culture turns cloudy as bacteria multiply; growth may appear as an even haze, a sediment at the bottom or a film, the pellicle, on the surface, which hints at the organism’s oxygen needs. On agar slants, the colour, shape and texture of growth along the streak can be judged without opening the tube, reducing the risk of contamination.

Biochemical identification tests rely on the same visibility. In sugar fermentation tests, an indicator such as phenol red turns yellow when acid is produced, and gas collects in a small inverted Durham tube inside the larger one; the microbial fermentation testing tube is listed for that purpose. Motility and oxygen-requirement tests in semi-solid agar are read by looking for spreading growth or growth at particular depths. None of this is possible through amber glass, which is reserved for light-sensitive material.

The listing does not say whether the glass is borosilicate, or give the size, base shape or closure. Borosilicate glass is generally preferred for tubes that are autoclaved repeatedly. The amber glass culture vial is the alternative for light-sensitive contents.

Applications

• Broth cultures for observing growth patterns in microbiology practicals
• Agar slants and stabs for maintaining and examining pure cultures
• Sugar fermentation, indole and other biochemical identification tests
• Seed germination and small plant tissue culture set-ups that need to be watched

Care & Handling

• Autoclave used clear glass culture tubes with their contents before cleaning, then wash with detergent and a tube brush.
• Inspect tubes for chips and star cracks after each wash and discard damaged ones.
• Loosen caps before autoclaving so steam can enter and pressure can equalise.
• Find out the glass type before exposing tubes to sudden temperature changes.

Specifications

Why Choose LabEquip

Microbiology teaching labs and diagnostic training courses use clear culture tubes in every practical, so they are usually ordered in bulk. LabEquip lists them in Biology Lab Products; tell us the size and closure you need through the contact page.

Frequently Asked Questions

Why use clear glass culture tubes?

They let you see turbidity, sediment, pellicles, colour changes and gas bubbles without opening the tube, which is how most growth and biochemical tests are read.

What does the growth pattern in a broth tube show?

In thioglycollate broth, growth only at the top suggests an organism that needs oxygen, growth only at the bottom suggests an anaerobe, and growth throughout suggests a facultative organism.

How is gas production detected in a culture tube?

A small inverted Durham tube is placed inside the culture tube before sterilising. If the organism produces gas while fermenting the sugar, a bubble collects at the top of the Durham tube.

Can clear glass culture tubes be autoclaved?

Borosilicate glass tubes are generally autoclavable many times. Soda-lime glass is less tolerant of heat, and the listing does not name the glass type, so confirm it when you enquire.

When should I use amber tubes instead?

Use amber when the medium or reagent is damaged by light, such as solutions containing riboflavin or certain antibiotics. For watching growth, clear glass is better.

How do I clean tubes with dried agar?

Autoclave them first to melt and sterilise the agar, pour off the liquid medium while hot, then scrub with detergent and a tube brush and rinse with distilled water.

Last Updated: September 2026