Plastic vs Glass vs Stainless Steel Fermenting Vessels: What are the Differences?

There are so many fermenting vessels on the market these days. We have so many more options now than we did when I first got started brewing 15-ish years ago! But, when faced with the choices of plastic, glass, or stainless steel, which one is best? What are the pros and cons of each material?

Fermentors of any material will do just fine. Plastic fermentors are extremely cheap and beginner-friendly, but are prone to scratches that can harbor contaminants. Glass is cleaner and longer-lasting, but can be heavy and dangerous when it breaks. Stainless steel is the best of both worlds, but is extremely expensive.

Any fermentor will do, but different materials have very different characteristics.

I’ll get into the details of each below, but as a quick summary:

Plastic fermentors – specifically cheap food-grade buckets -are great for those getting into the hobby or those who don’t want to spend too much.

Glass should largely be avoided for primary fermentation (although I do enjoy my Little Big Mouth Bubblers) but carboys are actually great for any brews (such as mead or wine) that must be bulk-aged in a secondary vessel.

Stainless steel is basically the best of both worlds, and even has extra benefits like being pressure-ready, but is extremely expensive – prohibitively so for the majority of homebrewers.

Whatever you do, make sure to always get a fermenting vessel with a spigot if at all possible. Not only does it reduce costs and make transferring the brew from one vessel to another (or to a keg or bottle) easier, it drastically reduces the chances of oxidation when doing so.

Plastic Fermentors: What are the Pros and Cons?

Plastic fermentors are great for beginner brewers, because they allow you to get into the hobby without spending too much money. You can get cheap food-grade plastic buckets (with spigots!) for as cheap as $5, and the brew will ferment just as good in that vessel as it will in the fancy ones.

You will likely go through these buckets faster than glass or stainless steel vessels, however, simply because plastic is more prone to getting deep scratches. Never use a plastic fermentor that has these deep scratches – it can harbor bacteria, wild yeast, and mold spores that are impossible to get out! Fortunately, plastic buckets are incredibly useful and can be repurposed for things like grain storage, sanitizing your equipment on brew day, or non-homebrewing household DIY projects.

Additionally, plastic fermentors can come in much more functional form factors such as conicals and even the pressure-ready FermZilla All-Rounder – for a higher price, of course.

Plastic buckets are very inexpensive and great for new or budget-minded brewers!

The Benefits of Plastic Fermentors

Plastic vessels are very cheap. You can buy a bunch of food-grade buckets for less than one of most other kinds of fermentors.
Plastic is sturdy, especially when compared to glass. Your bucket is not likely to break if you drop it.
Even if you do break the vessel, plastic shards aren’t nearly as dangerous as other material.
Plastic is lighter than glass, too, making it easier to move the vessel around even when full.

The Issues with Plastic Fermentors

The biggest issue is that plastic fermentors are prone to getting scratched – not just small scratches, but deep gouges. These gouges can harbor contaminants, and it’s basically impossible to clean within the gouges. Once you have scratches inside your plastic fermentor, every future fermentation that occurs within it is likely to be contaminated.
Plastic itself is actually porous, and air from the outside environment can eventually get in. It appears to take time for the air to penetrate through the plastic, and thicker vessels can further protect from this. Primary fermentation should usually be complete before you see oxidation or other problems; however, you likely don’t want to use plastic for your secondary vessel when bulk-aging for longer periods of time.
This porousness can supposedly also allow critters to penetrate into the vessel. The rule of thumb is that, if you have an infected brew that fermented in plastic, do not use that vessel again – unless you want another wild fermentation. I have not personally experienced this, but I have heard and read about it countless times.

Glass Fermentors: What are the Pros and Cons?

Glass is a bit more expensive than plastic, and requires complete carefulness, but if you take care of it and don’t break it, the vessel will last you a much longer time.

Glass is less prone to plastic and is far easier to clean to a spotless state. Since it isn’t porous, it can be easily cleaned, sanitized, and reused even after contamination occurs.

However, glass comes almost exclusively in the form of narrow-necked carboys. These are awful for fermentation, providing little headspace for krausen, and are incredibly difficult to clean since you can’t get your hand in there.

What they are great for, however, is bulk aging. Wines, meads, and very high-gravity beers that need to spend months in a secondary vessel to let flavors meld and to age out fermentation by-products can sit in a carboy after fermentation is complete. The small headspace is great for protecting the brew post-fermentation, as it can quickly fill up with CO₂ and push the oxygen out. You also don’t need to worry as much about cleaning, since there won’t be solid bits like fruit or hops to make a mess at this stage, and fermentation isn’t happening, so there won’t be yeasty gunk around the edges.

For primary fermentation, I suggest looking into the Big Mouth Bubbler. This has become one of my favorite fermentation vessels – especially for smaller batches. Just make sure to get the type with a spigot!

Glass has its uses. Carboys are particularly nice for bulk aging

The Benefits of Glass Fermentors

Glass is resistant to scratches, so it is less likely to harbor bacteria
Glass is not porous, so contaminants cannot penetrate into the material.
Since glass is not porous, it is completely airtight and watertight. If the vessel remains sealed, it will protect the brew from oxidation indefinitely.
Glass is incredibly easy to clean and sanitize – as long as you can get your hand in and scrub!

The Issues with Glass Fermentors

Glass is dangerous – so much so that many brewers avoid it entirely. If you drop your glass fermentor, you don’t just make a mess, you scatter dangerous glass shards that cut up and/or get lodged in everything, and can send you to the hospital to get stitches – or worse.
Glass is also much heavier than the alternatives, especially when full, and especially when brewing bigger batches. Glass vessels usually don’t come with handles, either. You have to be extra careful when moving the fermentor around, and remember that if you drop it, you could really injure yourself.

Stainless Steel Fermentors: What are the Pros and Cons?

Stainless steel is legitimately the best of both worlds. It’s nonporous and easy to clean like glass, while being sturdy and break-proof like plastic. Basically no downsides! Except….

It’s so dang expensive. You can go through ten plastic buckets before you’ve spent as much as even the cheapest stainless steel fermentors!

If you’ve been brewing for a while, you know that you’ll keep brewing, and you’re ready to level up your equipment game (and ready to spend the money to do so) then you really can’t go wrong with stainless steel. Cost aside, you won’t regret it.

But if you’re unsure at all about the purchase, then don’t worry about it. Better equipment won’t automatically make better homebrew, it’ll just make it a bit easier for you.

The Benefits of Stainless Steel Fermentors

Stainless steel is the highest quality, but also very expensive!

Stainless steel is sturdy. It’s not going to break from a drop – or from almost anything you’re likely to do to it. It’ll last you a very long time. Additionally, since it’s not likely to shatter, it’s not as dangerous as glass.
Stainless steel is very light, making it roughly as easy to move the vessel as it is with plastic.
Stainless steel is very resistant to scratches, and even when they occur, the scratches can be buffed out. This makes it not only incredibly resilient and long-lasting, but also infection-resistant. Bacteria and other contaminants cannot harbor in stainless steel like they can in plastic.
Stainless steel is also easy to clean, similar to glass.
Stainless steel is not porous. Contaminants cannot penetrate the material. If you have an infection in one batch, your stainless steel equipment is not compromised.
Since it is not porous, stainless steel is airtight and watertight. A sealed stainless steel vessel will keep oxygen out indefinitely, preventing oxidation even throughout a long aging process.

The Issues with Stainless Steel Fermentors

COST. Stainless steel brewing equipment of any kind is extremely expensive, and fermentors are no exception. They’re great, but the price is probably not worth it for most brewers.

What Should You Buy?

Now you know the differences between each kind of fermentor, but what do you do with this information? Which fermentor should you buy?

The answer is a little more complicated than just “this one” or “that one.” It really depends on you – your budget, experience, and passion for the hobby.

If you’re incredibly experienced and passionate about homebrewing, and you’ve given yourself some leeway with your budget, then the answer is extremely obvious. Stainless steel fermentors are the best of all worlds and, if you brew often and don’t mind the price, you will not regret upgrading.

On the complete opposite end of the spectrum, if you’re new to the hobby or unsure, or if you simply cannot spend much, then just use plastic buckets. You will still make great homebrew in a plastic bucket, and it is extremely cheap. You might need to replace it every so often, but buckets are so cheap that you’ll still be within budget after a few of them.

For those in the middle, I have a suggestion. At least, I can tell you what I do – and it’s not all stainless steel!

I suggest buying a mix of plastic and glass – have a few fermentation vessels of each kind, and use them for different purposes.

Plastic is great for primary fermentation. If you only brew relatively standard-gravity beers, that’s all you need. Buckets are great, but if you’re willing to spend a bit more on an upgrade, I’d suggest a conical-shaped plastic fermentor like the BrewDemon – just don’t get the 1 gallon version, it’s not very good!

Check out my review of the BrewDemon 3 gallon conical fermenter! Spoiler: it’s my favorite fermenter around that size.

Glass carboys are terrible for primary fermentation, but if you find yourself doing a number of batches that need to be bulk-aged, such as wines and meads, then it’s nice to keep a few of these around for that purpose. You can brew the batch in your plastic fermentation vessel first, and then once fermentation is complete (after a few days to a few weeks), immediately transfer it to your carboy, freeing up the plastic vessel for a new batch.

The Big Mouth Bubbler is a great glass fermentor. I like it for small batches, such as this stout. Just be sure to get the one with a spigot!

I also really like the Big Mouth Bubbler for primary fermentation, especially for smaller batches. It has a number of benefits over your standard glass vessel, such as thicker walls (making it sturdier), the big mouth it gets its name from (allowing you to get your hand inside for cleaning), and it even has a version with a spigot!

Always get the one with the spigot.

Beyond that, I suggest playing around with it. Start with a bucket, or with a combination of different vessels if your passion and budget allow, and experiment with them to see what works for your preferences and routine.

There are also a lot of different form factors to consider, but that goes beyond the scope of this article. Keep a lookout for future reviews of the different kinds of fermentors!

Conclusion

Feel free to follow my suggestions when purchasing your own fermentation vessels, or branch out on your own, experiment, and figure it out for yourself!

Regardless of what you do, you know have the knowledge to make an informed decision.