How to Build and Use a Still Air Box (SAB)

A Still Air Box (SAB) is an essential tool for mushroom cultivation, helping growers maintain a controlled, contamination-free workspace. Whether you’re a beginner or an experienced cultivator, an SAB is a simple, affordable, and effective way to create a sterile environment without the need for expensive laminar flow hoods.

In this guide, we’ll walk you through how to build an SAB, explain why it works, and share best practices for using it effectively.

What is a Still Air Box?

A Still Air Box (SAB) is a sealed workspace designed to minimize airborne contaminants. By reducing air movement, it prevents dust, mold spores, and bacteria from settling onto sterile materials such as agar plates, grain jars, or liquid culture containers.

Why Use an SAB?

• Budget-Friendly Alternative – Unlike laminar flow hoods, an SAB is inexpensive and easy to construct.

• Increased Sterility – Reduces airborne contaminants during inoculation and transfers.

• Simple Setup – Requires only a plastic tote and basic tools.

Building Your Still Air Box

Step 1: Choose Your Tote

• Select a clear plastic tote that’s large enough to comfortably fit your tools and workspace.

• A 66-quart tote is a popular size, but you can scale up if needed.

• Transparency is key—you’ll want to see your work inside.

Step 2: Cut Arm Holes

1. Mark two circles, about 5 inches in diameter, on one long side of the tote.

2. Cut the holes using one of the following methods:

   • Hole saw for clean edges.

   • Heated can to melt through the plastic.

   • Box cutter on warmed plastic for easier cutting.

3. Smooth the edges to prevent glove tears or arm discomfort.

Step 3: Set Up the SAB

• Flip the tote upside down so the open side faces the table.

• Place it on a clean, stable surface.

• Your SAB is now ready for use!

Using Your Still Air Box Effectively

Step 1: Prep Your Workspace

• Turn off fans, heaters, or AC units to eliminate airflow.

• Clean the surface under the SAB with 70% isopropyl alcohol.

• Spray and wipe down the inside of the SAB with 70% isopropyl alcohol.

Step 2: Trap Contaminants

• Lightly mist the SAB’s walls and ceiling with water mixed with a drop of dish soap to trap airborne particles.

Step 3: Sanitize Your Tools

• Wipe down jars, scalpels, syringes, and other tools with 70% isopropyl alcohol before placing them inside.

Step 4: Let the Air Settle

• Wait at least one minute before starting work to allow disturbed air to settle.

Best Practices for Success

• Stay Clean: Wash hands, wear clean clothes, and always use gloves.

• Plan Ahead: Gather everything you need before starting to avoid unnecessary openings.

• Move Slowly: Keep movements deliberate and steady to maintain still air.

• Avoid Over-Spraying: Too much alcohol on hands can cause flaking, adding contaminants.

• Limit Talking: Speaking over the workspace increases contamination risks.

Why the SAB Method Works

Unlike laminar flow hoods that push sterile air, an SAB works by keeping air still, preventing contaminants from circulating. By limiting airflow, airborne contaminants settle, reducing the risk of contamination in sterile processes.

With proper use, an SAB allows cultivators to confidently perform inoculations, transfers, and agar work while minimizing contamination risks.

Final Thoughts: A Must-Have for Sterile Cultivation

Building and using a Still Air Box is one of the simplest and most effective ways to maintain sterility in mushroom cultivation. Whether you’re preparing grain spawn, making agar transfers, or inoculating liquid cultures, an SAB provides a cost-effective and reliable solution for maintaining a clean workspace.

By following this guide, you’re taking a significant step toward consistent, healthy mushroom growth. Happy cultivating!

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