🍶 Demijohns and Glass Fermenters for Home Brewing
When it comes to fermenting drinks, demijohns and glass fermenters are iconic pieces of equipment. Traditionally used for wine, these glass containers are also perfect for cider, mead, beer, and even homemade cordials or syrups that require controlled fermentation. Their clear design makes them not only practical but also a favourite for brewers who like to watch fermentation in action.
🪣 Buckets vs. Demijohns – When to Use Each
Fermenting buckets are generally the best choice for primary fermentation. This early stage is often vigorous, with froth and bubbles that need plenty of headspace. Demijohns, on the other hand, come into their own for secondary fermentation—when the activity has slowed down considerably.
At this stage, less headspace is required. The narrow neck of a demijohn reduces oxygen exposure thanks to the smaller surface area of liquid, which helps lower the risk of oxidation and spoilage. This makes demijohns ideal for the finishing stages of wine, cider, or mead production.
👀 Why Choose Glass for Fermentation?
Unlike plastic, glass fermenters don’t scratch easily, which reduces the risk of harbouring bacteria in hidden grooves. They are also non-porous, meaning they won’t absorb odours or flavours from previous batches. This makes them ideal for brewers who want consistency and purity from batch to batch.
📏 Sizes and Options
Demijohns typically come in 1-gallon (4.5L) sizes, making them perfect for small experimental batches. Larger glass fermenters can hold 5 gallons (22–23L), which suits more committed home brewers. Many people start with smaller demijohns to trial recipes before scaling up to larger batches.
🌬 Using Demijohns with Airlocks
Almost all glass fermenters are designed to be used with a bung and airlock system. This ensures that carbon dioxide produced during fermentation can escape safely, while keeping oxygen and contaminants out. Choosing a bung that fits snugly is essential—many demijohn kits come with one included.
🧴 Plastic Demijohns – Budget-Friendly but Short-Lived
Not all demijohns are made of glass. Plastic bottle-style demijohns are widely available and can be very cost-effective for beginners. They’re lightweight and won’t shatter if dropped.
However, the thin plastic doesn’t last long—scratches can harbour bacteria, and cleaning them thoroughly is more difficult. They’re a good choice for those new to brewing and looking to keep costs down, but expect to replace them after a few uses if you stick with winemaking, cider, or beer.
💪 The Downside of Glass
While glass has its advantages, it’s not without drawbacks. A full demijohn is heavy and fragile, meaning extra care is needed when lifting or cleaning. Breakages can be messy and dangerous. Some brewers prefer to use plastic alternatives for larger batches to avoid the risks.
🧽 Cleaning Demijohns and Glass Fermenters
Cleaning can be more challenging than with wide-mouthed buckets. Narrow-necked demijohns often require a bottle brush to scrub properly. Rinsing with steriliser after each use is vital to prevent contamination and to keep the glass sparkling clear for your next batch.
🛒 Where to Buy Demijohns and Glass Fermenters
Demijohns are widely available in both traditional and modern designs. You can buy single units or starter sets that include bungs and airlocks. They’re an affordable way to get started with small-batch brewing.
👉 Browse a wide selection of demijohns and glass fermenters on Amazon here: Search Demijohns on Amazon
🍷 Beginner Alcohol Brewing Equipment
This post is part of a comprehensive guide to home wine, cider, beer, and mead equipment. It covers one specific topic, but there are many other essential tools and additives you may need to create successful, clear, and tasty brews. For a full overview, visit our Wine & Brewing Equipment Page.
Here’s a quick list of all the posts in this series: