Rubber Carboy Blow-Off Hood (2-Spout) | Cap for Smooth-Neck Glass Fermenters

Rubber Carboy Blow-Off Hood | 2-Spout Cap for Smooth-Neck Fermenters

Secure, versatile cap for 3, 5, 6 & 6.5 gal glass carboys

This two-spout rubber carboy cap (aka “blow-off hood”) fits standard smooth-neck 3, 5, 6, and 6.5 gallon glass carboys. The dual openings let you run an airlock, blow-off tube, thermowell, or racking cane without juggling stoppers. It’s a clean, secure way to manage fermentation gas and transfers.

Key Features

• Two spouts, many uses: run an airlock and thermowell, a blow-off tube, or a racking cane through the cap
• Snug, reliable seal: grips smooth-neck glass carboys to help prevent slips and leaks
• Quick changeover: swap from blow-off to airlock without removing the cap
• Homebrewer-friendly: ideal for high-krausen fermentations and easy racking

Specifications

• Fit: Smooth-neck glass carboys (3, 5, 6, 6.5 gal)
• Openings: one small spout (~3/8" I.D.) for airlocks/thermowells/racking canes; one large spout (~1/2" I.D.) for blow-off tubing
• Material: Food-grade rubber
• Color: Varies by batch (commonly orange/red)

How to Use

1. Sanitize the cap, fittings, and any tubing.
2. Install the cap on the carboy neck. Seat fully for a snug seal.
3. Choose setup:
   • Blow-off: Insert 1/2" I.D. tubing into the large spout; place the other end in sanitizer.
   • Airlock: Insert airlock or thermowell/racking cane into the small spout (~3/8" I.D.).
4. Ferment as usual; swap from blow-off to airlock when krausen subsides.

Compatibility Notes

• Designed for smooth-neck glass carboys.
• Not for threaded PET (BetterBottle-style) carboys unless using a compatible adapter.

Recommended Add-Ons

• 3/8" thermowell and 1/2" I.D. blow-off tubing
• Airlock (S-shaped or 3-piece)
• Hose clamp for extra security if desired